kjuulh/rhai
1
0
Fork 0
Code Issues 1 Pull Requests 1 Packages Projects Releases Wiki Activity
f2b1184805
rhai/src/parser.rs
Stephen Chung 5d275b5307 Simplify to calc_fn_hash.
2022-09-21 11:46:23 +08:00

3948 lines
148 KiB
Rust
Raw Blame History

//! Main module defining the lexer and parser.
use crate::api::events::VarDefInfo;
use crate::api::options::LangOptions;
use crate::ast::{
ASTFlags, BinaryExpr, CaseBlocksList, ConditionalExpr, Expr, FnCallExpr, FnCallHashes, Ident,
OpAssignment, RangeCase, ScriptFnDef, Stmt, StmtBlock, StmtBlockContainer,
SwitchCasesCollection, TryCatchBlock,
};
use crate::engine::{Precedence, KEYWORD_THIS, OP_CONTAINS};
use crate::eval::GlobalRuntimeState;
use crate::func::{hashing::get_hasher, StraightHashMap};
use crate::tokenizer::{
is_keyword_function, is_valid_function_name, is_valid_identifier, Token, TokenStream,
TokenizerControl,
};
use crate::types::dynamic::AccessMode;
use crate::types::StringsInterner;
use crate::{
calc_fn_hash, Dynamic, Engine, EvalAltResult, EvalContext, ExclusiveRange, Identifier,
ImmutableString, InclusiveRange, LexError, OptimizationLevel, ParseError, Position, Scope,
Shared, SmartString, StaticVec, AST, INT, PERR,
};
#[cfg(feature = "no_std")]
use std::prelude::v1::*;
use std::{
collections::BTreeMap,
fmt,
hash::{Hash, Hasher},
num::{NonZeroU8, NonZeroUsize},
};
pub type ParseResult<T> = Result<T, ParseError>;
type FnLib = StraightHashMap<Shared<ScriptFnDef>>;
const KEYWORD_SEMICOLON: &str = Token::SemiColon.literal_syntax();
const KEYWORD_CLOSE_BRACE: &str = Token::RightBrace.literal_syntax();
/// Invalid variable name that acts as a search barrier in a [`Scope`].
const SCOPE_SEARCH_BARRIER_MARKER: &str = "$ BARRIER $";
/// The message: `TokenStream` never ends
const NEVER_ENDS: &str = "`Token`";
/// Unroll `switch` ranges no larger than this.
const SMALL_SWITCH_RANGE: INT = 16;
/// Number of string interners used: two additional for property getters/setters if not `no_object`
const NUM_INTERNERS: usize = if cfg!(feature = "no_object") { 1 } else { 3 };
/// _(internals)_ A type that encapsulates the current state of the parser.
/// Exported under the `internals` feature only.
pub struct ParseState<'e> {
/// Input stream buffer containing the next character to read.
pub tokenizer_control: TokenizerControl,
/// Controls whether parsing of an expression should stop given the next token.
pub expr_filter: fn(&Token) -> bool,
/// String interners.
interned_strings: [StringsInterner<'e>; NUM_INTERNERS],
/// External [scope][Scope] with constants.
pub scope: &'e Scope<'e>,
/// Global runtime state.
pub global: GlobalRuntimeState<'e>,
/// Encapsulates a local stack with variable names to simulate an actual runtime scope.
pub stack: Scope<'e>,
/// Size of the local variables stack upon entry of the current block scope.
pub block_stack_len: usize,
/// Tracks a list of external variables (variables that are not explicitly declared in the scope).
#[cfg(not(feature = "no_closure"))]
pub external_vars: Vec<crate::ast::Ident>,
/// An indicator that disables variable capturing into externals one single time
/// up until the nearest consumed Identifier token.
/// If set to false the next call to [`access_var`][ParseState::access_var] will not capture the variable.
/// All consequent calls to [`access_var`][ParseState::access_var] will not be affected.
#[cfg(not(feature = "no_closure"))]
pub allow_capture: bool,
/// Encapsulates a local stack with imported [module][crate::Module] names.
#[cfg(not(feature = "no_module"))]
pub imports: StaticVec<ImmutableString>,
/// List of globally-imported [module][crate::Module] names.
#[cfg(not(feature = "no_module"))]
pub global_imports: StaticVec<ImmutableString>,
/// Maximum levels of expression nesting (0 for unlimited).
#[cfg(not(feature = "unchecked"))]
pub max_expr_depth: usize,
}
impl fmt::Debug for ParseState<'_> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
let mut f = f.debug_struct("ParseState");
f.field("tokenizer_control", &self.tokenizer_control)
.field("interned_strings", &self.interned_strings)
.field("scope", &self.scope)
.field("global", &self.global)
.field("stack", &self.stack)
.field("block_stack_len", &self.block_stack_len);
#[cfg(not(feature = "no_closure"))]
f.field("external_vars", &self.external_vars)
.field("allow_capture", &self.allow_capture);
#[cfg(not(feature = "no_module"))]
f.field("imports", &self.imports)
.field("global_imports", &self.global_imports);
#[cfg(not(feature = "unchecked"))]
f.field("max_expr_depth", &self.max_expr_depth);
f.finish()
}
}
impl<'e> ParseState<'e> {
/// Create a new [`ParseState`].
#[inline(always)]
#[must_use]
pub fn new(
engine: &Engine,
scope: &'e Scope,
interned_strings: [StringsInterner<'e>; NUM_INTERNERS],
tokenizer_control: TokenizerControl,
) -> Self {
Self {
tokenizer_control,
expr_filter: |_| true,
#[cfg(not(feature = "no_closure"))]
external_vars: Vec::new(),
#[cfg(not(feature = "no_closure"))]
allow_capture: true,
interned_strings,
scope,
global: GlobalRuntimeState::new(engine),
stack: Scope::new(),
block_stack_len: 0,
#[cfg(not(feature = "no_module"))]
imports: StaticVec::new_const(),
#[cfg(not(feature = "no_module"))]
global_imports: StaticVec::new_const(),
#[cfg(not(feature = "unchecked"))]
max_expr_depth: engine.max_expr_depth(),
}
}
/// Find explicitly declared variable by name in the [`ParseState`], searching in reverse order.
///
/// The first return value is the offset to be deducted from `ParseState::stack::len()`,
/// i.e. the top element of [`ParseState`]'s variables stack is offset 1.
///
/// If the variable is not present in the scope, the first return value is zero.
///
/// The second return value indicates whether the barrier has been hit before finding the variable.
#[must_use]
pub fn find_var(&self, name: &str) -> (usize, bool) {
let mut hit_barrier = false;
(
self.stack
.iter_rev_raw()
.enumerate()
.find(|&(.., (n, ..))| {
if n == SCOPE_SEARCH_BARRIER_MARKER {
// Do not go beyond the barrier
hit_barrier = true;
false
} else {
n == name
}
})
.map_or(0, |(i, ..)| i + 1),
hit_barrier,
)
}
/// Find explicitly declared variable by name in the [`ParseState`], searching in reverse order.
///
/// If the variable is not present in the scope adds it to the list of external variables.
///
/// The return value is the offset to be deducted from `ParseState::stack::len()`,
/// i.e. the top element of [`ParseState`]'s variables stack is offset 1.
///
/// # Return value: `(index, is_func_name)`
///
/// * `index`: `None` when the variable name is not found in the `stack`,
/// otherwise the index value.
///
/// * `is_func_name`: `true` if the variable is actually the name of a function
/// (in which case it will be converted into a function pointer).
#[inline]
#[must_use]
pub fn access_var(
&mut self,
name: &str,
lib: &FnLib,
pos: Position,
) -> (Option<NonZeroUsize>, bool) {
let _lib = lib;
let _pos = pos;
let (index, hit_barrier) = self.find_var(name);
#[cfg(not(feature = "no_function"))]
let is_func_name = _lib.values().any(|f| f.name == name);
#[cfg(feature = "no_function")]
let is_func_name = false;
#[cfg(not(feature = "no_closure"))]
if self.allow_capture {
if !is_func_name && index == 0 && !self.external_vars.iter().any(|v| v.as_str() == name)
{
self.external_vars.push(crate::ast::Ident {
name: name.into(),
pos: _pos,
});
}
} else {
self.allow_capture = true;
}
let index = if hit_barrier {
None
} else {
NonZeroUsize::new(index)
};
(index, is_func_name)
}
/// Find a module by name in the [`ParseState`], searching in reverse.
///
/// Returns the offset to be deducted from `Stack::len`,
/// i.e. the top element of the [`ParseState`] is offset 1.
///
/// Returns `None` when the variable name is not found in the [`ParseState`].
///
/// # Panics
///
/// Panics when called under `no_module`.
#[cfg(not(feature = "no_module"))]
#[inline]
#[must_use]
pub fn find_module(&self, name: &str) -> Option<NonZeroUsize> {
self.imports
.iter()
.rev()
.enumerate()
.find(|(.., n)| n.as_str() == name)
.and_then(|(i, ..)| NonZeroUsize::new(i + 1))
}
/// Get an interned string, creating one if it is not yet interned.
#[inline(always)]
#[must_use]
pub fn get_interned_string(
&mut self,
text: impl AsRef<str> + Into<ImmutableString>,
) -> ImmutableString {
self.interned_strings[0].get(text)
}
/// Get an interned property getter, creating one if it is not yet interned.
#[cfg(not(feature = "no_object"))]
#[inline(always)]
#[must_use]
pub fn get_interned_getter(
&mut self,
text: impl AsRef<str> + Into<ImmutableString>,
) -> ImmutableString {
self.interned_strings[1]
.get_with_mapper(|s| crate::engine::make_getter(s.as_ref()).into(), text)
}
/// Get an interned property setter, creating one if it is not yet interned.
#[cfg(not(feature = "no_object"))]
#[inline(always)]
#[must_use]
pub fn get_interned_setter(
&mut self,
text: impl AsRef<str> + Into<ImmutableString>,
) -> ImmutableString {
self.interned_strings[2]
.get_with_mapper(|s| crate::engine::make_setter(s.as_ref()).into(), text)
}
}
/// A type that encapsulates all the settings for a particular parsing function.
#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
struct ParseSettings {
/// Is the construct being parsed located at global level?
at_global_level: bool,
/// Is the construct being parsed located inside a function definition?
#[cfg(not(feature = "no_function"))]
in_fn_scope: bool,
/// Is the construct being parsed located inside a closure definition?
#[cfg(not(feature = "no_function"))]
#[cfg(not(feature = "no_closure"))]
in_closure: bool,
/// Is the construct being parsed located inside a breakable loop?
is_breakable: bool,
/// Allow statements in blocks?
allow_statements: bool,
/// Language options in effect (overrides Engine options).
options: LangOptions,
/// Current expression nesting level.
level: usize,
/// Current position.
pos: Position,
}
impl ParseSettings {
/// Create a new `ParseSettings` with one higher expression level.
#[inline(always)]
#[must_use]
pub const fn level_up(&self) -> Self {
Self {
level: self.level + 1,
..*self
}
}
/// Make sure that the current level of expression nesting is within the maximum limit.
///
/// If `limit` is zero, then checking is disabled.
#[cfg(not(feature = "unchecked"))]
#[inline]
pub fn ensure_level_within_max_limit(&self, limit: usize) -> ParseResult<()> {
if limit > 0 && self.level > limit {
return Err(PERR::ExprTooDeep.into_err(self.pos));
}
Ok(())
}
}
/// Make an anonymous function.
#[cfg(not(feature = "no_function"))]
#[inline]
#[must_use]
pub fn make_anonymous_fn(hash: u64) -> String {
format!("{}{:016x}", crate::engine::FN_ANONYMOUS, hash)
}
/// Is this function an anonymous function?
#[cfg(not(feature = "no_function"))]
#[inline(always)]
#[must_use]
pub fn is_anonymous_fn(fn_name: &str) -> bool {
fn_name.starts_with(crate::engine::FN_ANONYMOUS)
}
impl Expr {
/// Convert a [`Variable`][Expr::Variable] into a [`Property`][Expr::Property].
/// All other variants are untouched.
#[cfg(not(feature = "no_object"))]
#[inline]
#[must_use]
fn into_property(self, state: &mut ParseState) -> Self {
match self {
#[cfg(not(feature = "no_module"))]
Self::Variable(x, ..) if !x.1.is_empty() => unreachable!("qualified property"),
Self::Variable(x, .., pos) => {
let ident = x.3.clone();
let getter = state.get_interned_getter(ident.as_str());
let hash_get = calc_fn_hash(None, &getter, 1);
let setter = state.get_interned_setter(ident.as_str());
let hash_set = calc_fn_hash(None, &setter, 2);
Self::Property(
Box::new(((getter, hash_get), (setter, hash_set), ident)),
pos,
)
}
_ => self,
}
}
/// Raise an error if the expression can never yield a boolean value.
fn ensure_bool_expr(self) -> ParseResult<Expr> {
let type_name = match self {
Expr::Unit(..) => "()",
Expr::DynamicConstant(ref v, ..) if !v.is::<bool>() => v.type_name(),
Expr::IntegerConstant(..) => "a number",
#[cfg(not(feature = "no_float"))]
Expr::FloatConstant(..) => "a floating-point number",
Expr::CharConstant(..) => "a character",
Expr::StringConstant(..) => "a string",
Expr::InterpolatedString(..) => "a string",
Expr::Array(..) => "an array",
Expr::Map(..) => "an object map",
_ => return Ok(self),
};
Err(
PERR::MismatchedType("a boolean expression".to_string(), type_name.to_string())
.into_err(self.start_position()),
)
}
/// Raise an error if the expression can never yield an iterable value.
fn ensure_iterable(self) -> ParseResult<Expr> {
let type_name = match self {
Expr::Unit(..) => "()",
Expr::BoolConstant(..) => "a boolean",
Expr::IntegerConstant(..) => "a number",
#[cfg(not(feature = "no_float"))]
Expr::FloatConstant(..) => "a floating-point number",
Expr::CharConstant(..) => "a character",
Expr::Map(..) => "an object map",
_ => return Ok(self),
};
Err(
PERR::MismatchedType("an iterable value".to_string(), type_name.to_string())
.into_err(self.start_position()),
)
}
}
/// Make sure that the next expression is not a statement expression (i.e. wrapped in `{}`).
#[inline]
fn ensure_not_statement_expr(
input: &mut TokenStream,
type_name: &(impl ToString + ?Sized),
) -> ParseResult<()> {
match input.peek().expect(NEVER_ENDS) {
(Token::LeftBrace, pos) => Err(PERR::ExprExpected(type_name.to_string()).into_err(*pos)),
_ => Ok(()),
}
}
/// Make sure that the next expression is not a mis-typed assignment (i.e. `a = b` instead of `a == b`).
#[inline]
fn ensure_not_assignment(input: &mut TokenStream) -> ParseResult<()> {
match input.peek().expect(NEVER_ENDS) {
(Token::Equals, pos) => Err(LexError::ImproperSymbol(
"=".to_string(),
"Possibly a typo of '=='?".to_string(),
)
.into_err(*pos)),
_ => Ok(()),
}
}
/// Consume a particular [token][Token], checking that it is the expected one.
///
/// # Panics
///
/// Panics if the next token is not the expected one.
#[inline]
fn eat_token(input: &mut TokenStream, expected_token: Token) -> Position {
let (t, pos) = input.next().expect(NEVER_ENDS);
if t != expected_token {
unreachable!(
"{} expected but gets {} at {}",
expected_token.syntax(),
t.syntax(),
pos
);
}
pos
}
/// Match a particular [token][Token], consuming it if matched.
#[inline]
fn match_token(input: &mut TokenStream, token: Token) -> (bool, Position) {
let (t, pos) = input.peek().expect(NEVER_ENDS);
if *t == token {
(true, eat_token(input, token))
} else {
(false, *pos)
}
}
/// Parse a variable name.
#[inline]
fn parse_var_name(input: &mut TokenStream) -> ParseResult<(SmartString, Position)> {
match input.next().expect(NEVER_ENDS) {
// Variable name
(Token::Identifier(s), pos) => Ok((s, pos)),
// Reserved keyword
(Token::Reserved(s), pos) if is_valid_identifier(s.chars()) => {
Err(PERR::Reserved(s.to_string()).into_err(pos))
}
// Bad identifier
(Token::LexError(err), pos) => Err(err.into_err(pos)),
// Not a variable name
(.., pos) => Err(PERR::VariableExpected.into_err(pos)),
}
}
/// Parse a symbol.
#[cfg(not(feature = "no_custom_syntax"))]
#[inline]
fn parse_symbol(input: &mut TokenStream) -> ParseResult<(SmartString, Position)> {
match input.next().expect(NEVER_ENDS) {
// Symbol
(token, pos) if token.is_standard_symbol() => Ok((token.literal_syntax().into(), pos)),
// Reserved symbol
(Token::Reserved(s), pos) if !is_valid_identifier(s.chars()) => Ok((s, pos)),
// Bad symbol
(Token::LexError(err), pos) => Err(err.into_err(pos)),
// Not a symbol
(.., pos) => Err(PERR::MissingSymbol(String::new()).into_err(pos)),
}
}
impl Engine {
/// Parse `(` expr `)`
fn parse_paren_expr(
&self,
input: &mut TokenStream,
state: &mut ParseState,
lib: &mut FnLib,
settings: ParseSettings,
) -> ParseResult<Expr> {
#[cfg(not(feature = "unchecked"))]
settings.ensure_level_within_max_limit(state.max_expr_depth)?;
// ( ...
let mut settings = settings;
settings.pos = eat_token(input, Token::LeftParen);
let expr = self.parse_expr(input, state, lib, settings.level_up())?;
match input.next().expect(NEVER_ENDS) {
// ( ... )
(Token::RightParen, ..) => Ok(expr),
// ( <error>
(Token::LexError(err), pos) => Err(err.into_err(pos)),
// ( ... ???
(.., pos) => Err(PERR::MissingToken(
Token::RightParen.into(),
"for a matching ( in this expression".into(),
)
.into_err(pos)),
}
}
/// Parse a function call.
fn parse_fn_call(
&self,
input: &mut TokenStream,
state: &mut ParseState,
lib: &mut FnLib,
id: ImmutableString,
no_args: bool,
capture_parent_scope: bool,
#[cfg(not(feature = "no_module"))] namespace: crate::ast::Namespace,
settings: ParseSettings,
) -> ParseResult<Expr> {
#[cfg(not(feature = "unchecked"))]
settings.ensure_level_within_max_limit(state.max_expr_depth)?;
let (token, token_pos) = if no_args {
&(Token::RightParen, Position::NONE)
} else {
input.peek().expect(NEVER_ENDS)
};
#[cfg(not(feature = "no_module"))]
let mut namespace = namespace;
let mut args = StaticVec::new_const();
match token {
// id( <EOF>
Token::EOF => {
return Err(PERR::MissingToken(
Token::RightParen.into(),
format!("to close the arguments list of this function call '{id}'"),
)
.into_err(*token_pos))
}
// id( <error>
Token::LexError(err) => return Err(err.clone().into_err(*token_pos)),
// id()
Token::RightParen => {
if !no_args {
eat_token(input, Token::RightParen);
}
#[cfg(not(feature = "no_module"))]
let hash = if namespace.is_empty() {
calc_fn_hash(None, &id, 0)
} else {
let root = namespace.root();
let index = state.find_module(root);
#[cfg(not(feature = "no_function"))]
#[cfg(not(feature = "no_module"))]
let is_global = root == crate::engine::KEYWORD_GLOBAL;
#[cfg(any(feature = "no_function", feature = "no_module"))]
let is_global = false;
if settings.options.contains(LangOptions::STRICT_VAR)
&& index.is_none()
&& !is_global
&& !state.global_imports.iter().any(|m| m.as_str() == root)
&& !self.global_sub_modules.contains_key(root)
{
return Err(
PERR::ModuleUndefined(root.to_string()).into_err(namespace.position())
);
}
namespace.set_index(index);
crate::calc_fn_hash(namespace.iter().map(Ident::as_str), &id, 0)
};
#[cfg(feature = "no_module")]
let hash = calc_fn_hash(None, &id, 0);
let hashes = if is_valid_function_name(&id) {
hash.into()
} else {
FnCallHashes::from_native(hash)
};
args.shrink_to_fit();
return Ok(FnCallExpr {
name: state.get_interned_string(id),
capture_parent_scope,
is_native_operator: false,
#[cfg(not(feature = "no_module"))]
namespace,
hashes,
args,
pos: settings.pos,
}
.into_fn_call_expr(settings.pos));
}
// id...
_ => (),
}
let settings = settings.level_up();
loop {
match input.peek().expect(NEVER_ENDS) {
// id(...args, ) - handle trailing comma
(Token::RightParen, ..) => (),
_ => args.push(self.parse_expr(input, state, lib, settings)?),
}
match input.peek().expect(NEVER_ENDS) {
// id(...args)
(Token::RightParen, ..) => {
eat_token(input, Token::RightParen);
#[cfg(not(feature = "no_module"))]
let hash = if namespace.is_empty() {
calc_fn_hash(None, &id, args.len())
} else {
let root = namespace.root();
let index = state.find_module(root);
#[cfg(not(feature = "no_function"))]
#[cfg(not(feature = "no_module"))]
let is_global = root == crate::engine::KEYWORD_GLOBAL;
#[cfg(any(feature = "no_function", feature = "no_module"))]
let is_global = false;
if settings.options.contains(LangOptions::STRICT_VAR)
&& index.is_none()
&& !is_global
&& !state.global_imports.iter().any(|m| m.as_str() == root)
&& !self.global_sub_modules.contains_key(root)
{
return Err(PERR::ModuleUndefined(root.to_string())
.into_err(namespace.position()));
}
namespace.set_index(index);
crate::calc_fn_hash(namespace.iter().map(Ident::as_str), &id, args.len())
};
#[cfg(feature = "no_module")]
let hash = calc_fn_hash(None, &id, args.len());
let hashes = if is_valid_function_name(&id) {
hash.into()
} else {
FnCallHashes::from_native(hash)
};
args.shrink_to_fit();
return Ok(FnCallExpr {
name: state.get_interned_string(id),
capture_parent_scope,
is_native_operator: false,
#[cfg(not(feature = "no_module"))]
namespace,
hashes,
args,
pos: settings.pos,
}
.into_fn_call_expr(settings.pos));
}
// id(...args,
(Token::Comma, ..) => {
eat_token(input, Token::Comma);
}
// id(...args <EOF>
(Token::EOF, pos) => {
return Err(PERR::MissingToken(
Token::RightParen.into(),
format!("to close the arguments list of this function call '{id}'"),
)
.into_err(*pos))
}
// id(...args <error>
(Token::LexError(err), pos) => return Err(err.clone().into_err(*pos)),
// id(...args ???
(.., pos) => {
return Err(PERR::MissingToken(
Token::Comma.into(),
format!("to separate the arguments to function call '{id}'"),
)
.into_err(*pos))
}
}
}
}
/// Parse an indexing chain.
/// Indexing binds to the right, so this call parses all possible levels of indexing following in the input.
#[cfg(not(feature = "no_index"))]
fn parse_index_chain(
&self,
input: &mut TokenStream,
state: &mut ParseState,
lib: &mut FnLib,
lhs: Expr,
options: ASTFlags,
check_index_type: bool,
settings: ParseSettings,
) -> ParseResult<Expr> {
#[cfg(not(feature = "unchecked"))]
settings.ensure_level_within_max_limit(state.max_expr_depth)?;
let mut settings = settings;
let idx_expr = self.parse_expr(input, state, lib, settings.level_up())?;
// Check types of indexing that cannot be overridden
// - arrays, maps, strings, bit-fields
match lhs {
_ if !check_index_type => (),
Expr::Map(..) => match idx_expr {
// lhs[int]
Expr::IntegerConstant(..) => {
return Err(PERR::MalformedIndexExpr(
"Object map expects string index, not a number".into(),
)
.into_err(idx_expr.start_position()))
}
// lhs[string]
Expr::StringConstant(..) | Expr::InterpolatedString(..) => (),
// lhs[float]
#[cfg(not(feature = "no_float"))]
Expr::FloatConstant(..) => {
return Err(PERR::MalformedIndexExpr(
"Object map expects string index, not a float".into(),
)
.into_err(idx_expr.start_position()))
}
// lhs[char]
Expr::CharConstant(..) => {
return Err(PERR::MalformedIndexExpr(
"Object map expects string index, not a character".into(),
)
.into_err(idx_expr.start_position()))
}
// lhs[()]
Expr::Unit(..) => {
return Err(PERR::MalformedIndexExpr(
"Object map expects string index, not ()".into(),
)
.into_err(idx_expr.start_position()))
}
// lhs[??? && ???], lhs[??? || ???], lhs[true], lhs[false]
Expr::And(..) | Expr::Or(..) | Expr::BoolConstant(..) => {
return Err(PERR::MalformedIndexExpr(
"Object map expects string index, not a boolean".into(),
)
.into_err(idx_expr.start_position()))
}
_ => (),
},
Expr::IntegerConstant(..)
| Expr::Array(..)
| Expr::StringConstant(..)
| Expr::InterpolatedString(..) => match idx_expr {
// lhs[int]
Expr::IntegerConstant(..) => (),
// lhs[string]
Expr::StringConstant(..) | Expr::InterpolatedString(..) => {
return Err(PERR::MalformedIndexExpr(
"Array, string or bit-field expects numeric index, not a string".into(),
)
.into_err(idx_expr.start_position()))
}
// lhs[float]
#[cfg(not(feature = "no_float"))]
Expr::FloatConstant(..) => {
return Err(PERR::MalformedIndexExpr(
"Array, string or bit-field expects integer index, not a float".into(),
)
.into_err(idx_expr.start_position()))
}
// lhs[char]
Expr::CharConstant(..) => {
return Err(PERR::MalformedIndexExpr(
"Array, string or bit-field expects integer index, not a character".into(),
)
.into_err(idx_expr.start_position()))
}
// lhs[()]
Expr::Unit(..) => {
return Err(PERR::MalformedIndexExpr(
"Array, string or bit-field expects integer index, not ()".into(),
)
.into_err(idx_expr.start_position()))
}
// lhs[??? && ???], lhs[??? || ???], lhs[true], lhs[false]
Expr::And(..) | Expr::Or(..) | Expr::BoolConstant(..) => {
return Err(PERR::MalformedIndexExpr(
"Array, string or bit-field expects integer index, not a boolean".into(),
)
.into_err(idx_expr.start_position()))
}
_ => (),
},
_ => (),
}
// Check if there is a closing bracket
match input.peek().expect(NEVER_ENDS) {
(Token::RightBracket, ..) => {
eat_token(input, Token::RightBracket);
// Any more indexing following?
match input.peek().expect(NEVER_ENDS) {
// If another indexing level, right-bind it
(Token::LeftBracket | Token::QuestionBracket, ..) => {
let (token, pos) = input.next().expect(NEVER_ENDS);
let prev_pos = settings.pos;
settings.pos = pos;
// Recursively parse the indexing chain, right-binding each
let idx_expr = self.parse_index_chain(
input,
state,
lib,
idx_expr,
match token {
Token::LeftBracket => ASTFlags::NONE,
Token::QuestionBracket => ASTFlags::NEGATED,
_ => unreachable!("`[` or `?[`"),
},
false,
settings.level_up(),
)?;
// Indexing binds to right
Ok(Expr::Index(
BinaryExpr { lhs, rhs: idx_expr }.into(),
options,
prev_pos,
))
}
// Otherwise terminate the indexing chain
_ => Ok(Expr::Index(
BinaryExpr { lhs, rhs: idx_expr }.into(),
options | ASTFlags::BREAK,
settings.pos,
)),
}
}
(Token::LexError(err), pos) => Err(err.clone().into_err(*pos)),
(.., pos) => Err(PERR::MissingToken(
Token::RightBracket.into(),
"for a matching [ in this index expression".into(),
)
.into_err(*pos)),
}
}
/// Parse an array literal.
#[cfg(not(feature = "no_index"))]
fn parse_array_literal(
&self,
input: &mut TokenStream,
state: &mut ParseState,
lib: &mut FnLib,
settings: ParseSettings,
) -> ParseResult<Expr> {
#[cfg(not(feature = "unchecked"))]
settings.ensure_level_within_max_limit(state.max_expr_depth)?;
// [ ...
let mut settings = settings;
settings.pos = eat_token(input, Token::LeftBracket);
let mut array = StaticVec::new_const();
loop {
const MISSING_RBRACKET: &str = "to end this array literal";
#[cfg(not(feature = "unchecked"))]
if self.max_array_size() > 0 && array.len() >= self.max_array_size() {
return Err(PERR::LiteralTooLarge(
"Size of array literal".to_string(),
self.max_array_size(),
)
.into_err(input.peek().expect(NEVER_ENDS).1));
}
match input.peek().expect(NEVER_ENDS) {
(Token::RightBracket, ..) => {
eat_token(input, Token::RightBracket);
break;
}
(Token::EOF, pos) => {
return Err(PERR::MissingToken(
Token::RightBracket.into(),
MISSING_RBRACKET.into(),
)
.into_err(*pos))
}
_ => {
let expr = self.parse_expr(input, state, lib, settings.level_up())?;
array.push(expr);
}
}
match input.peek().expect(NEVER_ENDS) {
(Token::Comma, ..) => {
eat_token(input, Token::Comma);
}
(Token::RightBracket, ..) => (),
(Token::EOF, pos) => {
return Err(PERR::MissingToken(
Token::RightBracket.into(),
MISSING_RBRACKET.into(),
)
.into_err(*pos))
}
(Token::LexError(err), pos) => return Err(err.clone().into_err(*pos)),
(.., pos) => {
return Err(PERR::MissingToken(
Token::Comma.into(),
"to separate the items of this array literal".into(),
)
.into_err(*pos))
}
};
}
array.shrink_to_fit();
Ok(Expr::Array(array.into(), settings.pos))
}
/// Parse a map literal.
#[cfg(not(feature = "no_object"))]
fn parse_map_literal(
&self,
input: &mut TokenStream,
state: &mut ParseState,
lib: &mut FnLib,
settings: ParseSettings,
) -> ParseResult<Expr> {
#[cfg(not(feature = "unchecked"))]
settings.ensure_level_within_max_limit(state.max_expr_depth)?;
// #{ ...
let mut settings = settings;
settings.pos = eat_token(input, Token::MapStart);
let mut map = StaticVec::<(Ident, Expr)>::new();
let mut template = BTreeMap::<Identifier, crate::Dynamic>::new();
loop {
const MISSING_RBRACE: &str = "to end this object map literal";
match input.peek().expect(NEVER_ENDS) {
(Token::RightBrace, ..) => {
eat_token(input, Token::RightBrace);
break;
}
(Token::EOF, pos) => {
return Err(
PERR::MissingToken(Token::RightBrace.into(), MISSING_RBRACE.into())
.into_err(*pos),
)
}
_ => (),
}
let (name, pos) = match input.next().expect(NEVER_ENDS) {
(Token::Identifier(s) | Token::StringConstant(s), pos) => {
if map.iter().any(|(p, ..)| **p == s) {
return Err(PERR::DuplicatedProperty(s.to_string()).into_err(pos));
}
(s, pos)
}
(Token::InterpolatedString(..), pos) => {
return Err(PERR::PropertyExpected.into_err(pos))
}
(Token::Reserved(s), pos) if is_valid_identifier(s.chars()) => {
return Err(PERR::Reserved(s.to_string()).into_err(pos));
}
(Token::LexError(err), pos) => return Err(err.into_err(pos)),
(Token::EOF, pos) => {
return Err(PERR::MissingToken(
Token::RightBrace.into(),
MISSING_RBRACE.into(),
)
.into_err(pos));
}
(.., pos) if map.is_empty() => {
return Err(PERR::MissingToken(
Token::RightBrace.into(),
MISSING_RBRACE.into(),
)
.into_err(pos));
}
(.., pos) => return Err(PERR::PropertyExpected.into_err(pos)),
};
match input.next().expect(NEVER_ENDS) {
(Token::Colon, ..) => (),
(Token::LexError(err), pos) => return Err(err.into_err(pos)),
(.., pos) => {
return Err(PERR::MissingToken(
Token::Colon.into(),
format!("to follow the property '{name}' in this object map literal"),
)
.into_err(pos))
}
};
#[cfg(not(feature = "unchecked"))]
if self.max_map_size() > 0 && map.len() >= self.max_map_size() {
return Err(PERR::LiteralTooLarge(
"Number of properties in object map literal".to_string(),
self.max_map_size(),
)
.into_err(input.peek().expect(NEVER_ENDS).1));
}
let expr = self.parse_expr(input, state, lib, settings.level_up())?;
template.insert(name.clone(), crate::Dynamic::UNIT);
let name = state.get_interned_string(name);
map.push((Ident { name, pos }, expr));
match input.peek().expect(NEVER_ENDS) {
(Token::Comma, ..) => {
eat_token(input, Token::Comma);
}
(Token::RightBrace, ..) => (),
(Token::Identifier(..), pos) => {
return Err(PERR::MissingToken(
Token::Comma.into(),
"to separate the items of this object map literal".into(),
)
.into_err(*pos))
}
(Token::LexError(err), pos) => return Err(err.clone().into_err(*pos)),
(.., pos) => {
return Err(
PERR::MissingToken(Token::RightBrace.into(), MISSING_RBRACE.into())
.into_err(*pos),
)
}
}
}
map.shrink_to_fit();
Ok(Expr::Map((map, template).into(), settings.pos))
}
/// Parse a switch expression.
fn parse_switch(
&self,
input: &mut TokenStream,
state: &mut ParseState,
lib: &mut FnLib,
settings: ParseSettings,
) -> ParseResult<Stmt> {
#[cfg(not(feature = "unchecked"))]
settings.ensure_level_within_max_limit(state.max_expr_depth)?;
// switch ...
let mut settings = settings;
settings.pos = eat_token(input, Token::Switch);
let item = self.parse_expr(input, state, lib, settings.level_up())?;
match input.next().expect(NEVER_ENDS) {
(Token::LeftBrace, ..) => (),
(Token::LexError(err), pos) => return Err(err.into_err(pos)),
(.., pos) => {
return Err(PERR::MissingToken(
Token::LeftBrace.into(),
"to start a switch block".into(),
)
.into_err(pos))
}
}
let mut expressions = StaticVec::<ConditionalExpr>::new();
let mut cases = BTreeMap::<u64, CaseBlocksList>::new();
let mut ranges = StaticVec::<RangeCase>::new();
let mut def_case = None;
let mut def_case_pos = Position::NONE;
loop {
const MISSING_RBRACE: &str = "to end this switch block";
let (case_expr_list, condition) = match input.peek().expect(NEVER_ENDS) {
(Token::RightBrace, ..) => {
eat_token(input, Token::RightBrace);
break;
}
(Token::EOF, pos) => {
return Err(
PERR::MissingToken(Token::RightBrace.into(), MISSING_RBRACE.into())
.into_err(*pos),
)
}
(Token::Underscore, pos) if def_case.is_none() => {
def_case_pos = *pos;
eat_token(input, Token::Underscore);
let (if_clause, if_pos) = match_token(input, Token::If);
if if_clause {
return Err(PERR::WrongSwitchCaseCondition.into_err(if_pos));
}
(
StaticVec::default(),
Expr::BoolConstant(true, Position::NONE),
)
}
_ if def_case.is_some() => {
return Err(PERR::WrongSwitchDefaultCase.into_err(def_case_pos))
}
_ => {
let mut case_expr_list = StaticVec::new();
loop {
let filter = state.expr_filter;
state.expr_filter = |t| t != &Token::Pipe;
let expr = self.parse_expr(input, state, lib, settings.level_up());
state.expr_filter = filter;
match expr {
Ok(expr) => case_expr_list.push(expr),
Err(err) => {
return Err(PERR::ExprExpected("literal".into()).into_err(err.1))
}
}
if !match_token(input, Token::Pipe).0 {
break;
}
}
let condition = if match_token(input, Token::If).0 {
ensure_not_statement_expr(input, "a boolean")?;
let guard = self
.parse_expr(input, state, lib, settings.level_up())?
.ensure_bool_expr()?;
ensure_not_assignment(input)?;
guard
} else {
Expr::BoolConstant(true, Position::NONE)
};
(case_expr_list, condition)
}
};
match input.next().expect(NEVER_ENDS) {
(Token::DoubleArrow, ..) => (),
(Token::LexError(err), pos) => return Err(err.into_err(pos)),
(.., pos) => {
return Err(PERR::MissingToken(
Token::DoubleArrow.into(),
"in this switch case".to_string(),
)
.into_err(pos))
}
};
let (action_expr, need_comma) = if settings.allow_statements {
let stmt = self.parse_stmt(input, state, lib, settings.level_up())?;
let need_comma = !stmt.is_self_terminated();
let stmt_block: StmtBlock = stmt.into();
(Expr::Stmt(stmt_block.into()), need_comma)
} else {
(
self.parse_expr(input, state, lib, settings.level_up())?,
true,
)
};
let has_condition = !matches!(condition, Expr::BoolConstant(true, ..));
expressions.push((condition, action_expr).into());
let index = expressions.len() - 1;
if case_expr_list.is_empty() {
def_case = Some(index);
} else {
for expr in case_expr_list {
let value = expr.get_literal_value().ok_or_else(|| {
PERR::ExprExpected("a literal".to_string()).into_err(expr.start_position())
})?;
let mut range_value: Option<RangeCase> = None;
let guard = value.read_lock::<ExclusiveRange>();
if let Some(range) = guard {
range_value = Some(range.clone().into());
} else if let Some(range) = value.read_lock::<InclusiveRange>() {
range_value = Some(range.clone().into());
}
if let Some(mut r) = range_value {
if !r.is_empty() {
// Do not unroll ranges if there are previous non-unrolled ranges
if !has_condition && ranges.is_empty() && r.len() <= SMALL_SWITCH_RANGE
{
// Unroll small range
for n in r {
let hasher = &mut get_hasher();
Dynamic::from_int(n).hash(hasher);
cases
.entry(hasher.finish())
.and_modify(|cases| cases.push(index))
.or_insert_with(|| [index].into());
}
} else {
// Other range
r.set_index(index);
ranges.push(r);
}
}
continue;
}
if value.is::<INT>() && !ranges.is_empty() {
return Err(PERR::WrongSwitchIntegerCase.into_err(expr.start_position()));
}
let hasher = &mut get_hasher();
value.hash(hasher);
let hash = hasher.finish();
cases
.entry(hash)
.and_modify(|cases| cases.push(index))
.or_insert_with(|| [index].into());
}
}
match input.peek().expect(NEVER_ENDS) {
(Token::Comma, ..) => {
eat_token(input, Token::Comma);
}
(Token::RightBrace, ..) => (),
(Token::EOF, pos) => {
return Err(
PERR::MissingToken(Token::RightParen.into(), MISSING_RBRACE.into())
.into_err(*pos),
)
}
(Token::LexError(err), pos) => return Err(err.clone().into_err(*pos)),
(.., pos) if need_comma => {
return Err(PERR::MissingToken(
Token::Comma.into(),
"to separate the items in this switch block".into(),
)
.into_err(*pos))
}
_ => (),
}
}
let cases = SwitchCasesCollection {
expressions,
cases,
def_case,
ranges,
};
Ok(Stmt::Switch((item, cases).into(), settings.pos))
}
/// Parse a primary expression.
fn parse_primary(
&self,
input: &mut TokenStream,
state: &mut ParseState,
lib: &mut FnLib,
is_property: bool,
settings: ParseSettings,
) -> ParseResult<Expr> {
#[cfg(not(feature = "unchecked"))]
settings.ensure_level_within_max_limit(state.max_expr_depth)?;
let (token, token_pos) = input.peek().expect(NEVER_ENDS);
let mut settings = settings;
settings.pos = *token_pos;
let root_expr = match token {
_ if !(state.expr_filter)(token) => {
return Err(
LexError::UnexpectedInput(token.syntax().to_string()).into_err(settings.pos)
)
}
Token::EOF => return Err(PERR::UnexpectedEOF.into_err(settings.pos)),
Token::Unit => {
input.next();
Expr::Unit(settings.pos)
}
Token::IntegerConstant(..)
| Token::CharConstant(..)
| Token::StringConstant(..)
| Token::True
| Token::False => match input.next().expect(NEVER_ENDS).0 {
Token::IntegerConstant(x) => Expr::IntegerConstant(x, settings.pos),
Token::CharConstant(c) => Expr::CharConstant(c, settings.pos),
Token::StringConstant(s) => {
Expr::StringConstant(state.get_interned_string(s), settings.pos)
}
Token::True => Expr::BoolConstant(true, settings.pos),
Token::False => Expr::BoolConstant(false, settings.pos),
token => unreachable!("token is {:?}", token),
},
#[cfg(not(feature = "no_float"))]
Token::FloatConstant(x) => {
let x = *x;
input.next();
Expr::FloatConstant(x, settings.pos)
}
#[cfg(feature = "decimal")]
Token::DecimalConstant(x) => {
let x = (*x).into();
input.next();
Expr::DynamicConstant(Box::new(x), settings.pos)
}
// { - block statement as expression
Token::LeftBrace if settings.options.contains(LangOptions::STMT_EXPR) => {
match self.parse_block(input, state, lib, settings.level_up())? {
block @ Stmt::Block(..) => Expr::Stmt(Box::new(block.into())),
stmt => unreachable!("Stmt::Block expected but gets {:?}", stmt),
}
}
// ( - grouped expression
Token::LeftParen => self.parse_paren_expr(input, state, lib, settings.level_up())?,
// If statement is allowed to act as expressions
Token::If if settings.options.contains(LangOptions::IF_EXPR) => Expr::Stmt(Box::new(
self.parse_if(input, state, lib, settings.level_up())?
.into(),
)),
// Switch statement is allowed to act as expressions
Token::Switch if settings.options.contains(LangOptions::SWITCH_EXPR) => {
Expr::Stmt(Box::new(
self.parse_switch(input, state, lib, settings.level_up())?
.into(),
))
}
// | ...
#[cfg(not(feature = "no_function"))]
Token::Pipe | Token::Or if settings.options.contains(LangOptions::ANON_FN) => {
// Build new parse state
let interned_strings = std::mem::take(&mut state.interned_strings);
let mut new_state = ParseState::new(
self,
state.scope,
interned_strings,
state.tokenizer_control.clone(),
);
#[cfg(not(feature = "no_module"))]
{
// Do not allow storing an index to a globally-imported module
// just in case the function is separated from this `AST`.
//
// Keep them in `global_imports` instead so that strict variables
// mode will not complain.
new_state.global_imports.clone_from(&state.global_imports);
new_state
.global_imports
.extend(state.imports.iter().cloned());
}
#[cfg(not(feature = "unchecked"))]
{
new_state.max_expr_depth = self.max_function_expr_depth();
}
let mut options = self.options;
options.set(
LangOptions::STRICT_VAR,
if cfg!(feature = "no_closure") {
settings.options.contains(LangOptions::STRICT_VAR)
} else {
// A capturing closure can access variables not defined locally
false
},
);
let new_settings = ParseSettings {
at_global_level: false,
in_fn_scope: true,
#[cfg(not(feature = "no_closure"))]
in_closure: true,
is_breakable: false,
level: 0,
options,
..settings
};
let result = self.parse_anon_fn(input, &mut new_state, lib, new_settings);
// Restore parse state
state.interned_strings = new_state.interned_strings;
let (expr, func) = result?;
#[cfg(not(feature = "no_closure"))]
new_state.external_vars.iter().try_for_each(
|crate::ast::Ident { name, pos }| {
let (index, is_func) = state.access_var(name, lib, *pos);
if !is_func
&& index.is_none()
&& !settings.in_closure
&& settings.options.contains(LangOptions::STRICT_VAR)
&& !state.scope.contains(name)
{
// If the parent scope is not inside another capturing closure
// then we can conclude that the captured variable doesn't exist.
// Under Strict Variables mode, this is not allowed.
Err(PERR::VariableUndefined(name.to_string()).into_err(*pos))
} else {
Ok::<_, ParseError>(())
}
},
)?;
let hash_script = calc_fn_hash(None, &func.name, func.params.len());
lib.insert(hash_script, func.into());
expr
}
// Interpolated string
Token::InterpolatedString(..) => {
let mut segments = StaticVec::<Expr>::new();
match input.next().expect(NEVER_ENDS) {
(Token::InterpolatedString(s), ..) if s.is_empty() => (),
(Token::InterpolatedString(s), pos) => {
segments.push(Expr::StringConstant(s.into(), pos))
}
token => {
unreachable!("Token::InterpolatedString expected but gets {:?}", token)
}
}
loop {
let expr = match self.parse_block(input, state, lib, settings.level_up())? {
block @ Stmt::Block(..) => Expr::Stmt(Box::new(block.into())),
stmt => unreachable!("Stmt::Block expected but gets {:?}", stmt),
};
match expr {
Expr::StringConstant(s, ..) if s.is_empty() => (),
_ => segments.push(expr),
}
// Make sure to parse the following as text
state.tokenizer_control.borrow_mut().is_within_text = true;
match input.next().expect(NEVER_ENDS) {
(Token::StringConstant(s), pos) => {
if !s.is_empty() {
segments.push(Expr::StringConstant(s.into(), pos));
}
// End the interpolated string if it is terminated by a back-tick.
break;
}
(Token::InterpolatedString(s), pos) => {
if !s.is_empty() {
segments.push(Expr::StringConstant(s.into(), pos));
}
}
(Token::LexError(err), pos)
if matches!(*err, LexError::UnterminatedString) =>
{
return Err(err.into_err(pos))
}
(token, ..) => unreachable!(
"string within an interpolated string literal expected but gets {:?}",
token
),
}
}
if segments.is_empty() {
Expr::StringConstant(state.get_interned_string(""), settings.pos)
} else {
segments.shrink_to_fit();
Expr::InterpolatedString(segments.into(), settings.pos)
}
}
// Array literal
#[cfg(not(feature = "no_index"))]
Token::LeftBracket => {
self.parse_array_literal(input, state, lib, settings.level_up())?
}
// Map literal
#[cfg(not(feature = "no_object"))]
Token::MapStart => self.parse_map_literal(input, state, lib, settings.level_up())?,
// Custom syntax.
#[cfg(not(feature = "no_custom_syntax"))]
Token::Custom(key) | Token::Reserved(key) | Token::Identifier(key)
if !self.custom_syntax.is_empty() && self.custom_syntax.contains_key(&**key) =>
{
let (key, syntax) = self.custom_syntax.get_key_value(&**key).unwrap();
let (.., pos) = input.next().expect(NEVER_ENDS);
let settings2 = settings.level_up();
self.parse_custom_syntax(input, state, lib, settings2, key, syntax, pos)?
}
// Identifier
Token::Identifier(..) => {
#[cfg(not(feature = "no_module"))]
let ns = crate::ast::Namespace::NONE;
#[cfg(feature = "no_module")]
let ns = ();
let s = match input.next().expect(NEVER_ENDS) {
(Token::Identifier(s), ..) => s,
token => unreachable!("Token::Identifier expected but gets {:?}", token),
};
match input.peek().expect(NEVER_ENDS).0 {
// Function call
Token::LeftParen | Token::Bang | Token::Unit => {
#[cfg(not(feature = "no_closure"))]
{
// Once the identifier consumed we must enable next variables capturing
state.allow_capture = true;
}
Expr::Variable(
(None, ns, 0, state.get_interned_string(s)).into(),
None,
settings.pos,
)
}
// Namespace qualification
#[cfg(not(feature = "no_module"))]
Token::DoubleColon => {
#[cfg(not(feature = "no_closure"))]
{
// Once the identifier consumed we must enable next variables capturing
state.allow_capture = true;
}
let name = state.get_interned_string(s);
Expr::Variable((None, ns, 0, name).into(), None, settings.pos)
}
// Normal variable access
_ => {
let (index, is_func) = state.access_var(&s, lib, settings.pos);
if !is_property
&& !is_func
&& index.is_none()
&& settings.options.contains(LangOptions::STRICT_VAR)
&& !state.scope.contains(&s)
{
return Err(
PERR::VariableUndefined(s.to_string()).into_err(settings.pos)
);
}
let short_index = index.and_then(|x| {
if x.get() <= u8::MAX as usize {
NonZeroU8::new(x.get() as u8)
} else {
None
}
});
let name = state.get_interned_string(s);
Expr::Variable((index, ns, 0, name).into(), short_index, settings.pos)
}
}
}
// Reserved keyword or symbol
Token::Reserved(..) => {
#[cfg(not(feature = "no_module"))]
let ns = crate::ast::Namespace::NONE;
#[cfg(feature = "no_module")]
let ns = ();
let s = match input.next().expect(NEVER_ENDS) {
(Token::Reserved(s), ..) => s,
token => unreachable!("Token::Reserved expected but gets {:?}", token),
};
match input.peek().expect(NEVER_ENDS).0 {
// Function call is allowed to have reserved keyword
Token::LeftParen | Token::Bang | Token::Unit if is_keyword_function(&s) => {
Expr::Variable(
(None, ns, 0, state.get_interned_string(s)).into(),
None,
settings.pos,
)
}
// Access to `this` as a variable is OK within a function scope
#[cfg(not(feature = "no_function"))]
_ if &*s == KEYWORD_THIS && settings.in_fn_scope => Expr::Variable(
(None, ns, 0, state.get_interned_string(s)).into(),
None,
settings.pos,
),
// Cannot access to `this` as a variable not in a function scope
_ if &*s == KEYWORD_THIS => {
let msg = format!("'{s}' can only be used in functions");
return Err(
LexError::ImproperSymbol(s.to_string(), msg).into_err(settings.pos)
);
}
_ => return Err(PERR::Reserved(s.to_string()).into_err(settings.pos)),
}
}
Token::LexError(..) => match input.next().expect(NEVER_ENDS) {
(Token::LexError(err), ..) => return Err(err.into_err(settings.pos)),
token => unreachable!("Token::LexError expected but gets {:?}", token),
},
_ => {
return Err(
LexError::UnexpectedInput(token.syntax().to_string()).into_err(settings.pos)
)
}
};
if !(state.expr_filter)(&input.peek().expect(NEVER_ENDS).0) {
return Ok(root_expr);
}
self.parse_postfix(input, state, lib, root_expr, settings)
}
/// Tail processing of all possible postfix operators of a primary expression.
fn parse_postfix(
&self,
input: &mut TokenStream,
state: &mut ParseState,
lib: &mut FnLib,
mut lhs: Expr,
settings: ParseSettings,
) -> ParseResult<Expr> {
let mut settings = settings;
// Tail processing all possible postfix operators
loop {
let (tail_token, ..) = input.peek().expect(NEVER_ENDS);
if !lhs.is_valid_postfix(tail_token) {
break;
}
let (tail_token, tail_pos) = input.next().expect(NEVER_ENDS);
settings.pos = tail_pos;
lhs = match (lhs, tail_token) {
// Qualified function call with !
#[cfg(not(feature = "no_module"))]
(Expr::Variable(x, ..), Token::Bang) if !x.1.is_empty() => {
return match input.peek().expect(NEVER_ENDS) {
(Token::LeftParen | Token::Unit, ..) => {
Err(LexError::UnexpectedInput(Token::Bang.syntax().to_string())
.into_err(tail_pos))
}
_ => Err(LexError::ImproperSymbol(
"!".to_string(),
"'!' cannot be used to call module functions".to_string(),
)
.into_err(tail_pos)),
};
}
// Function call with !
(Expr::Variable(x, .., pos), Token::Bang) => {
match input.peek().expect(NEVER_ENDS) {
(Token::LeftParen | Token::Unit, ..) => (),
(_, pos) => {
return Err(PERR::MissingToken(
Token::LeftParen.syntax().into(),
"to start arguments list of function call".into(),
)
.into_err(*pos))
}
}
let no_args = input.next().expect(NEVER_ENDS).0 == Token::Unit;
let (.., _ns, _, name) = *x;
settings.pos = pos;
self.parse_fn_call(
input,
state,
lib,
name,
no_args,
true,
#[cfg(not(feature = "no_module"))]
_ns,
settings.level_up(),
)?
}
// Function call
(Expr::Variable(x, .., pos), t @ (Token::LeftParen | Token::Unit)) => {
let (.., _ns, _, name) = *x;
settings.pos = pos;
self.parse_fn_call(
input,
state,
lib,
name,
t == Token::Unit,
false,
#[cfg(not(feature = "no_module"))]
_ns,
settings.level_up(),
)?
}
// module access
#[cfg(not(feature = "no_module"))]
(Expr::Variable(x, .., pos), Token::DoubleColon) => {
let (id2, pos2) = parse_var_name(input)?;
let (.., mut namespace, _, name) = *x;
let var_name_def = Ident { name, pos };
namespace.push(var_name_def);
Expr::Variable(
(None, namespace, 0, state.get_interned_string(id2)).into(),
None,
pos2,
)
}
// Indexing
#[cfg(not(feature = "no_index"))]
(expr, token @ (Token::LeftBracket | Token::QuestionBracket)) => {
let opt = match token {
Token::LeftBracket => ASTFlags::NONE,
Token::QuestionBracket => ASTFlags::NEGATED,
_ => unreachable!("`[` or `?[`"),
};
self.parse_index_chain(input, state, lib, expr, opt, true, settings.level_up())?
}
// Property access
#[cfg(not(feature = "no_object"))]
(expr, op @ (Token::Period | Token::Elvis)) => {
// Expression after dot must start with an identifier
match input.peek().expect(NEVER_ENDS) {
(Token::Identifier(..), ..) => {
#[cfg(not(feature = "no_closure"))]
{
// Prevents capturing of the object properties as vars: xxx.<var>
state.allow_capture = false;
}
}
(Token::Reserved(s), ..) if is_keyword_function(s) => (),
(.., pos) => return Err(PERR::PropertyExpected.into_err(*pos)),
}
let rhs = self.parse_primary(input, state, lib, true, settings.level_up())?;
let op_flags = match op {
Token::Period => ASTFlags::NONE,
Token::Elvis => ASTFlags::NEGATED,
_ => unreachable!("`.` or `?.`"),
};
Self::make_dot_expr(state, expr, rhs, ASTFlags::NONE, op_flags, tail_pos)?
}
// Unknown postfix operator
(expr, token) => unreachable!(
"unknown postfix operator '{}' for {:?}",
token.syntax(),
expr
),
}
}
// Cache the hash key for namespace-qualified variables
#[cfg(not(feature = "no_module"))]
let namespaced_variable = match lhs {
Expr::Variable(ref mut x, ..) if !x.1.is_empty() => Some(&mut **x),
Expr::Index(ref mut x, ..) | Expr::Dot(ref mut x, ..) => match x.lhs {
Expr::Variable(ref mut x, ..) if !x.1.is_empty() => Some(&mut **x),
_ => None,
},
_ => None,
};
#[cfg(not(feature = "no_module"))]
if let Some((.., namespace, hash, name)) = namespaced_variable {
if !namespace.is_empty() {
*hash = crate::calc_var_hash(namespace.iter().map(Ident::as_str), name);
#[cfg(not(feature = "no_module"))]
{
let root = namespace.root();
let index = state.find_module(root);
#[cfg(not(feature = "no_function"))]
#[cfg(not(feature = "no_module"))]
let is_global = root == crate::engine::KEYWORD_GLOBAL;
#[cfg(any(feature = "no_function", feature = "no_module"))]
let is_global = false;
if settings.options.contains(LangOptions::STRICT_VAR)
&& index.is_none()
&& !is_global
&& !state.global_imports.iter().any(|m| m.as_str() == root)
&& !self.global_sub_modules.contains_key(root)
{
return Err(
PERR::ModuleUndefined(root.to_string()).into_err(namespace.position())
);
}
namespace.set_index(index);
}
}
}
// Make sure identifiers are valid
Ok(lhs)
}
/// Parse a potential unary operator.
fn parse_unary(
&self,
input: &mut TokenStream,
state: &mut ParseState,
lib: &mut FnLib,
settings: ParseSettings,
) -> ParseResult<Expr> {
#[cfg(not(feature = "unchecked"))]
settings.ensure_level_within_max_limit(state.max_expr_depth)?;
let (token, token_pos) = input.peek().expect(NEVER_ENDS);
if !(state.expr_filter)(token) {
return Err(LexError::UnexpectedInput(token.syntax().to_string()).into_err(*token_pos));
}
let mut settings = settings;
settings.pos = *token_pos;
match token {
// -expr
Token::Minus | Token::UnaryMinus => {
let token = token.clone();
let pos = eat_token(input, token);
match self.parse_unary(input, state, lib, settings.level_up())? {
// Negative integer
Expr::IntegerConstant(num, ..) => num
.checked_neg()
.map(|i| Expr::IntegerConstant(i, pos))
.or_else(|| {
#[cfg(not(feature = "no_float"))]
return Some(Expr::FloatConstant((-(num as crate::FLOAT)).into(), pos));
#[cfg(feature = "no_float")]
return None;
})
.ok_or_else(|| LexError::MalformedNumber(format!("-{num}")).into_err(pos)),
// Negative float
#[cfg(not(feature = "no_float"))]
Expr::FloatConstant(x, ..) => Ok(Expr::FloatConstant((-(*x)).into(), pos)),
// Call negative function
expr => {
let mut args = StaticVec::new_const();
args.push(expr);
args.shrink_to_fit();
Ok(FnCallExpr {
name: state.get_interned_string("-"),
hashes: FnCallHashes::from_native(calc_fn_hash(None, "-", 1)),
args,
pos,
is_native_operator: true,
..Default::default()
}
.into_fn_call_expr(pos))
}
}
}
// +expr
Token::Plus | Token::UnaryPlus => {
let token = token.clone();
let pos = eat_token(input, token);
match self.parse_unary(input, state, lib, settings.level_up())? {
expr @ Expr::IntegerConstant(..) => Ok(expr),
#[cfg(not(feature = "no_float"))]
expr @ Expr::FloatConstant(..) => Ok(expr),
// Call plus function
expr => {
let mut args = StaticVec::new_const();
args.push(expr);
args.shrink_to_fit();
Ok(FnCallExpr {
name: state.get_interned_string("+"),
hashes: FnCallHashes::from_native(calc_fn_hash(None, "+", 1)),
args,
pos,
is_native_operator: true,
..Default::default()
}
.into_fn_call_expr(pos))
}
}
}
// !expr
Token::Bang => {
let pos = eat_token(input, Token::Bang);
let mut args = StaticVec::new_const();
args.push(self.parse_unary(input, state, lib, settings.level_up())?);
args.shrink_to_fit();
Ok(FnCallExpr {
name: state.get_interned_string("!"),
hashes: FnCallHashes::from_native(calc_fn_hash(None, "!", 1)),
args,
pos,
is_native_operator: true,
..Default::default()
}
.into_fn_call_expr(pos))
}
// <EOF>
Token::EOF => Err(PERR::UnexpectedEOF.into_err(settings.pos)),
// All other tokens
_ => self.parse_primary(input, state, lib, false, settings.level_up()),
}
}
/// Make an assignment statement.
fn make_assignment_stmt(
op: Option<Token>,
state: &mut ParseState,
lhs: Expr,
rhs: Expr,
op_pos: Position,
) -> ParseResult<Stmt> {
#[must_use]
fn check_lvalue(expr: &Expr, parent_is_dot: bool) -> Option<Position> {
match expr {
Expr::Index(x, options, ..) | Expr::Dot(x, options, ..) if parent_is_dot => {
match x.lhs {
Expr::Property(..) if !options.contains(ASTFlags::BREAK) => {
check_lvalue(&x.rhs, matches!(expr, Expr::Dot(..)))
}
Expr::Property(..) => None,
// Anything other than a property after dotting (e.g. a method call) is not an l-value
ref e => Some(e.position()),
}
}
Expr::Index(x, options, ..) | Expr::Dot(x, options, ..) => match x.lhs {
Expr::Property(..) => unreachable!("unexpected Expr::Property in indexing"),
_ if !options.contains(ASTFlags::BREAK) => {
check_lvalue(&x.rhs, matches!(expr, Expr::Dot(..)))
}
_ => None,
},
Expr::Property(..) if parent_is_dot => None,
Expr::Property(..) => unreachable!("unexpected Expr::Property in indexing"),
e if parent_is_dot => Some(e.position()),
_ => None,
}
}
let op_info = if let Some(ref op) = op {
OpAssignment::new_op_assignment_from_token(op, op_pos)
} else {
OpAssignment::new_assignment(op_pos)
};
match lhs {
// const_expr = rhs
ref expr if expr.is_constant() => {
Err(PERR::AssignmentToConstant("".into()).into_err(lhs.start_position()))
}
// var (non-indexed) = rhs
Expr::Variable(ref x, None, _) if x.0.is_none() => {
Ok(Stmt::Assignment((op_info, (lhs, rhs).into()).into()))
}
// var (indexed) = rhs
Expr::Variable(ref x, i, var_pos) => {
let (index, .., name) = &**x;
let index = i.map_or_else(
|| index.expect("either long or short index is `None`").get(),
|n| n.get() as usize,
);
match state
.stack
.get_mut_by_index(state.stack.len() - index)
.access_mode()
{
AccessMode::ReadWrite => {
Ok(Stmt::Assignment((op_info, (lhs, rhs).into()).into()))
}
// Constant values cannot be assigned to
AccessMode::ReadOnly => {
Err(PERR::AssignmentToConstant(name.to_string()).into_err(var_pos))
}
}
}
// xxx[???]... = rhs, xxx.prop... = rhs
Expr::Index(ref x, options, ..) | Expr::Dot(ref x, options, ..) => {
let valid_lvalue = if options.contains(ASTFlags::BREAK) {
None
} else {
check_lvalue(&x.rhs, matches!(lhs, Expr::Dot(..)))
};
match valid_lvalue {
None => {
match x.lhs {
// var[???] = rhs, var.??? = rhs
Expr::Variable(..) => {
Ok(Stmt::Assignment((op_info, (lhs, rhs).into()).into()))
}
// expr[???] = rhs, expr.??? = rhs
ref expr => Err(PERR::AssignmentToInvalidLHS(String::new())
.into_err(expr.position())),
}
}
Some(err_pos) => {
Err(PERR::AssignmentToInvalidLHS(String::new()).into_err(err_pos))
}
}
}
// ??? && ??? = rhs, ??? || ??? = rhs, xxx ?? xxx = rhs
Expr::And(..) | Expr::Or(..) | Expr::Coalesce(..) => Err(LexError::ImproperSymbol(
"=".to_string(),
"Possibly a typo of '=='?".to_string(),
)
.into_err(op_pos)),
// expr = rhs
_ => Err(PERR::AssignmentToInvalidLHS(String::new()).into_err(lhs.position())),
}
}
/// Parse an operator-assignment expression (if any).
fn parse_op_assignment_stmt(
&self,
input: &mut TokenStream,
state: &mut ParseState,
lib: &mut FnLib,
lhs: Expr,
settings: ParseSettings,
) -> ParseResult<Stmt> {
#[cfg(not(feature = "unchecked"))]
settings.ensure_level_within_max_limit(state.max_expr_depth)?;
let (op, pos) = match input.peek().expect(NEVER_ENDS) {
// var = ...
(Token::Equals, ..) => (None, eat_token(input, Token::Equals)),
// var op= ...
(token, ..) if token.is_op_assignment() => input
.next()
.map(|(op, pos)| (Some(op), pos))
.expect(NEVER_ENDS),
// Not op-assignment
_ => return Ok(Stmt::Expr(lhs.into())),
};
let mut settings = settings;
settings.pos = pos;
let rhs = self.parse_expr(input, state, lib, settings.level_up())?;
Self::make_assignment_stmt(op, state, lhs, rhs, pos)
}
/// Make a dot expression.
#[cfg(not(feature = "no_object"))]
fn make_dot_expr(
state: &mut ParseState,
lhs: Expr,
rhs: Expr,
parent_options: ASTFlags,
op_flags: ASTFlags,
op_pos: Position,
) -> ParseResult<Expr> {
match (lhs, rhs) {
// lhs[idx_expr].rhs
(Expr::Index(mut x, options, pos), rhs) => {
x.rhs = Self::make_dot_expr(
state,
x.rhs,
rhs,
options | parent_options,
op_flags,
op_pos,
)?;
Ok(Expr::Index(x, ASTFlags::NONE, pos))
}
// lhs.module::id - syntax error
#[cfg(not(feature = "no_module"))]
(.., Expr::Variable(x, ..)) if !x.1.is_empty() => {
Err(PERR::PropertyExpected.into_err(x.1.position()))
}
// lhs.id
(lhs, var_expr @ Expr::Variable(..)) => {
let rhs = var_expr.into_property(state);
Ok(Expr::Dot(BinaryExpr { lhs, rhs }.into(), op_flags, op_pos))
}
// lhs.prop
(lhs, prop @ Expr::Property(..)) => Ok(Expr::Dot(
BinaryExpr { lhs, rhs: prop }.into(),
op_flags,
op_pos,
)),
// lhs.nnn::func(...) - syntax error
#[cfg(not(feature = "no_module"))]
(.., Expr::FnCall(func, ..)) if func.is_qualified() => {
Err(PERR::PropertyExpected.into_err(func.namespace.position()))
}
// lhs.Fn() or lhs.eval()
(.., Expr::FnCall(func, func_pos))
if func.args.is_empty()
&& [crate::engine::KEYWORD_FN_PTR, crate::engine::KEYWORD_EVAL]
.contains(&func.name.as_str()) =>
{
let err_msg = format!(
"'{}' should not be called in method style. Try {}(...);",
func.name, func.name
);
Err(LexError::ImproperSymbol(func.name.to_string(), err_msg).into_err(func_pos))
}
// lhs.func!(...)
(.., Expr::FnCall(func, func_pos)) if func.capture_parent_scope => {
Err(PERR::MalformedCapture(
"method-call style does not support running within the caller's scope".into(),
)
.into_err(func_pos))
}
// lhs.func(...)
(lhs, Expr::FnCall(mut func, func_pos)) => {
// Recalculate hash
func.hashes = FnCallHashes::from_all(
#[cfg(not(feature = "no_function"))]
calc_fn_hash(None, &func.name, func.args.len()),
calc_fn_hash(None, &func.name, func.args.len() + 1),
);
let rhs = Expr::MethodCall(func, func_pos);
Ok(Expr::Dot(BinaryExpr { lhs, rhs }.into(), op_flags, op_pos))
}
// lhs.dot_lhs.dot_rhs or lhs.dot_lhs[idx_rhs]
(lhs, rhs @ (Expr::Dot(..) | Expr::Index(..))) => {
let (x, options, pos, is_dot) = match rhs {
Expr::Dot(x, options, pos) => (x, options, pos, true),
Expr::Index(x, options, pos) => (x, options, pos, false),
expr => unreachable!("Expr::Dot or Expr::Index expected but gets {:?}", expr),
};
match x.lhs {
// lhs.module::id.dot_rhs or lhs.module::id[idx_rhs] - syntax error
#[cfg(not(feature = "no_module"))]
Expr::Variable(x, ..) if !x.1.is_empty() => {
Err(PERR::PropertyExpected.into_err(x.1.position()))
}
// lhs.module::func().dot_rhs or lhs.module::func()[idx_rhs] - syntax error
#[cfg(not(feature = "no_module"))]
Expr::FnCall(func, ..) if func.is_qualified() => {
Err(PERR::PropertyExpected.into_err(func.namespace.position()))
}
// lhs.id.dot_rhs or lhs.id[idx_rhs]
Expr::Variable(..) | Expr::Property(..) => {
let new_binary = BinaryExpr {
lhs: x.lhs.into_property(state),
rhs: x.rhs,
}
.into();
let rhs = if is_dot {
Expr::Dot(new_binary, options, pos)
} else {
Expr::Index(new_binary, options, pos)
};
Ok(Expr::Dot(BinaryExpr { lhs, rhs }.into(), op_flags, op_pos))
}
// lhs.func().dot_rhs or lhs.func()[idx_rhs]
Expr::FnCall(mut func, func_pos) => {
// Recalculate hash
func.hashes = FnCallHashes::from_all(
#[cfg(not(feature = "no_function"))]
calc_fn_hash(None, &func.name, func.args.len()),
calc_fn_hash(None, &func.name, func.args.len() + 1),
);
let new_lhs = BinaryExpr {
lhs: Expr::MethodCall(func, func_pos),
rhs: x.rhs,
}
.into();
let rhs = if is_dot {
Expr::Dot(new_lhs, options, pos)
} else {
Expr::Index(new_lhs, options, pos)
};
Ok(Expr::Dot(BinaryExpr { lhs, rhs }.into(), op_flags, op_pos))
}
expr => unreachable!("invalid dot expression: {:?}", expr),
}
}
// lhs.rhs
(.., rhs) => Err(PERR::PropertyExpected.into_err(rhs.start_position())),
}
}
/// Parse a binary expression (if any).
fn parse_binary_op(
&self,
input: &mut TokenStream,
state: &mut ParseState,
lib: &mut FnLib,
parent_precedence: Option<Precedence>,
lhs: Expr,
settings: ParseSettings,
) -> ParseResult<Expr> {
#[cfg(not(feature = "unchecked"))]
settings.ensure_level_within_max_limit(state.max_expr_depth)?;
let mut settings = settings;
settings.pos = lhs.position();
let mut root = lhs;
loop {
let (current_op, current_pos) = input.peek().expect(NEVER_ENDS);
if !(state.expr_filter)(current_op) {
return Ok(root);
}
let precedence = match current_op {
#[cfg(not(feature = "no_custom_syntax"))]
Token::Custom(c) => self
.custom_keywords
.get(c)
.copied()
.ok_or_else(|| PERR::Reserved(c.to_string()).into_err(*current_pos))?,
Token::Reserved(c) if !is_valid_identifier(c.chars()) => {
return Err(PERR::UnknownOperator(c.to_string()).into_err(*current_pos))
}
_ => current_op.precedence(),
};
let bind_right = current_op.is_bind_right();
// Bind left to the parent lhs expression if precedence is higher
// If same precedence, then check if the operator binds right
if precedence < parent_precedence || (precedence == parent_precedence && !bind_right) {
return Ok(root);
}
let (op_token, pos) = input.next().expect(NEVER_ENDS);
let rhs = self.parse_unary(input, state, lib, settings)?;
let (next_op, next_pos) = input.peek().expect(NEVER_ENDS);
let next_precedence = match next_op {
#[cfg(not(feature = "no_custom_syntax"))]
Token::Custom(c) => self
.custom_keywords
.get(c)
.copied()
.ok_or_else(|| PERR::Reserved(c.to_string()).into_err(*next_pos))?,
Token::Reserved(c) if !is_valid_identifier(c.chars()) => {
return Err(PERR::UnknownOperator(c.to_string()).into_err(*next_pos))
}
_ => next_op.precedence(),
};
// Bind to right if the next operator has higher precedence
// If same precedence, then check if the operator binds right
let rhs =
if (precedence == next_precedence && bind_right) || precedence < next_precedence {
self.parse_binary_op(input, state, lib, precedence, rhs, settings)?
} else {
// Otherwise bind to left (even if next operator has the same precedence)
rhs
};
settings = settings.level_up();
settings.pos = pos;
#[cfg(not(feature = "unchecked"))]
settings.ensure_level_within_max_limit(state.max_expr_depth)?;
let op = op_token.syntax();
let hash = calc_fn_hash(None, &op, 2);
let op_base = FnCallExpr {
name: state.get_interned_string(op.as_ref()),
hashes: FnCallHashes::from_native(hash),
pos,
is_native_operator: !is_valid_function_name(&op),
..Default::default()
};
let mut args = StaticVec::new_const();
args.push(root);
args.push(rhs);
args.shrink_to_fit();
root = match op_token {
// '!=' defaults to true when passed invalid operands
Token::NotEqualsTo => FnCallExpr { args, ..op_base }.into_fn_call_expr(pos),
// Comparison operators default to false when passed invalid operands
Token::EqualsTo
| Token::LessThan
| Token::LessThanEqualsTo
| Token::GreaterThan
| Token::GreaterThanEqualsTo => {
let pos = args[0].start_position();
FnCallExpr { args, ..op_base }.into_fn_call_expr(pos)
}
Token::Or => {
let rhs = args.pop().unwrap();
let current_lhs = args.pop().unwrap();
Expr::Or(
BinaryExpr {
lhs: current_lhs.ensure_bool_expr()?,
rhs: rhs.ensure_bool_expr()?,
}
.into(),
pos,
)
}
Token::And => {
let rhs = args.pop().unwrap();
let current_lhs = args.pop().unwrap();
Expr::And(
BinaryExpr {
lhs: current_lhs.ensure_bool_expr()?,
rhs: rhs.ensure_bool_expr()?,
}
.into(),
pos,
)
}
Token::DoubleQuestion => {
let rhs = args.pop().unwrap();
let current_lhs = args.pop().unwrap();
Expr::Coalesce(
BinaryExpr {
lhs: current_lhs,
rhs,
}
.into(),
pos,
)
}
Token::In => {
// Swap the arguments
let current_lhs = args.remove(0);
let pos = current_lhs.start_position();
args.push(current_lhs);
args.shrink_to_fit();
// Convert into a call to `contains`
FnCallExpr {
hashes: calc_fn_hash(None, OP_CONTAINS, 2).into(),
args,
name: state.get_interned_string(OP_CONTAINS),
..op_base
}
.into_fn_call_expr(pos)
}
#[cfg(not(feature = "no_custom_syntax"))]
Token::Custom(s)
if self
.custom_keywords
.get(s.as_str())
.map_or(false, Option::is_some) =>
{
let hash = calc_fn_hash(None, &s, 2);
let pos = args[0].start_position();
FnCallExpr {
hashes: if is_valid_function_name(&s) {
hash.into()
} else {
FnCallHashes::from_native(hash)
},
args,
..op_base
}
.into_fn_call_expr(pos)
}
_ => {
let pos = args[0].start_position();
FnCallExpr { args, ..op_base }.into_fn_call_expr(pos)
}
};
}
}
/// Parse a custom syntax.
#[cfg(not(feature = "no_custom_syntax"))]
fn parse_custom_syntax(
&self,
input: &mut TokenStream,
state: &mut ParseState,
lib: &mut FnLib,
settings: ParseSettings,
key: impl Into<ImmutableString>,
syntax: &crate::api::custom_syntax::CustomSyntax,
pos: Position,
) -> ParseResult<Expr> {
use crate::api::custom_syntax::markers::*;
let mut settings = settings;
let mut inputs = StaticVec::<Expr>::new();
let mut segments = StaticVec::new_const();
let mut tokens = StaticVec::new_const();
// Adjust the variables stack
if syntax.scope_may_be_changed {
// Add a barrier variable to the stack so earlier variables will not be matched.
// Variable searches stop at the first barrier.
let marker = state.get_interned_string(SCOPE_SEARCH_BARRIER_MARKER);
state.stack.push(marker, ());
}
let mut user_state = Dynamic::UNIT;
let parse_func = &*syntax.parse;
let mut required_token: ImmutableString = key.into();
tokens.push(required_token.clone());
segments.push(required_token.clone());
loop {
let (fwd_token, fwd_pos) = input.peek().expect(NEVER_ENDS);
settings.pos = *fwd_pos;
let settings = settings.level_up();
required_token = match parse_func(&segments, &*fwd_token.syntax(), &mut user_state) {
Ok(Some(seg))
if seg.starts_with(CUSTOM_SYNTAX_MARKER_SYNTAX_VARIANT)
&& seg.len() > CUSTOM_SYNTAX_MARKER_SYNTAX_VARIANT.len() =>
{
inputs.push(Expr::StringConstant(state.get_interned_string(seg), pos));
break;
}
Ok(Some(seg)) => seg,
Ok(None) => break,
Err(err) => return Err(err.0.into_err(settings.pos)),
};
match required_token.as_str() {
CUSTOM_SYNTAX_MARKER_IDENT => {
let (name, pos) = parse_var_name(input)?;
let name = state.get_interned_string(name);
#[cfg(not(feature = "no_module"))]
let ns = crate::ast::Namespace::NONE;
#[cfg(feature = "no_module")]
let ns = ();
segments.push(name.clone().into());
tokens.push(state.get_interned_string(CUSTOM_SYNTAX_MARKER_IDENT));
inputs.push(Expr::Variable((None, ns, 0, name).into(), None, pos));
}
CUSTOM_SYNTAX_MARKER_SYMBOL => {
let (symbol, pos) = parse_symbol(input)?;
let symbol = state.get_interned_string(symbol);
segments.push(symbol.clone());
tokens.push(state.get_interned_string(CUSTOM_SYNTAX_MARKER_SYMBOL));
inputs.push(Expr::StringConstant(symbol, pos));
}
CUSTOM_SYNTAX_MARKER_EXPR => {
inputs.push(self.parse_expr(input, state, lib, settings)?);
let keyword = state.get_interned_string(CUSTOM_SYNTAX_MARKER_EXPR);
segments.push(keyword.clone().into());
tokens.push(keyword);
}
CUSTOM_SYNTAX_MARKER_BLOCK => {
match self.parse_block(input, state, lib, settings)? {
block @ Stmt::Block(..) => {
inputs.push(Expr::Stmt(Box::new(block.into())));
let keyword = state.get_interned_string(CUSTOM_SYNTAX_MARKER_BLOCK);
segments.push(keyword.clone().into());
tokens.push(keyword);
}
stmt => unreachable!("Stmt::Block expected but gets {:?}", stmt),
}
}
CUSTOM_SYNTAX_MARKER_BOOL => match input.next().expect(NEVER_ENDS) {
(b @ (Token::True | Token::False), pos) => {
inputs.push(Expr::BoolConstant(b == Token::True, pos));
segments.push(state.get_interned_string(b.literal_syntax()));
tokens.push(state.get_interned_string(CUSTOM_SYNTAX_MARKER_BOOL));
}
(.., pos) => {
return Err(
PERR::MissingSymbol("Expecting 'true' or 'false'".to_string())
.into_err(pos),
)
}
},
CUSTOM_SYNTAX_MARKER_INT => match input.next().expect(NEVER_ENDS) {
(Token::IntegerConstant(i), pos) => {
inputs.push(Expr::IntegerConstant(i, pos));
segments.push(i.to_string().into());
tokens.push(state.get_interned_string(CUSTOM_SYNTAX_MARKER_INT));
}
(.., pos) => {
return Err(
PERR::MissingSymbol("Expecting an integer number".to_string())
.into_err(pos),
)
}
},
#[cfg(not(feature = "no_float"))]
CUSTOM_SYNTAX_MARKER_FLOAT => match input.next().expect(NEVER_ENDS) {
(Token::FloatConstant(f), pos) => {
inputs.push(Expr::FloatConstant(f, pos));
segments.push(f.to_string().into());
tokens.push(state.get_interned_string(CUSTOM_SYNTAX_MARKER_FLOAT));
}
(.., pos) => {
return Err(PERR::MissingSymbol(
"Expecting a floating-point number".to_string(),
)
.into_err(pos))
}
},
CUSTOM_SYNTAX_MARKER_STRING => match input.next().expect(NEVER_ENDS) {
(Token::StringConstant(s), pos) => {
let s = state.get_interned_string(s);
inputs.push(Expr::StringConstant(s.clone(), pos));
segments.push(s);
tokens.push(state.get_interned_string(CUSTOM_SYNTAX_MARKER_STRING));
}
(.., pos) => {
return Err(
PERR::MissingSymbol("Expecting a string".to_string()).into_err(pos)
)
}
},
s => match input.next().expect(NEVER_ENDS) {
(Token::LexError(err), pos) => return Err(err.into_err(pos)),
(t, ..) if &*t.syntax() == s => {
segments.push(required_token.clone());
tokens.push(required_token.clone().into());
}
(.., pos) => {
return Err(PERR::MissingToken(
s.to_string(),
format!("for '{}' expression", segments[0]),
)
.into_err(pos))
}
},
}
}
inputs.shrink_to_fit();
tokens.shrink_to_fit();
let self_terminated = matches!(
required_token.as_str(),
// It is self-terminating if the last symbol is a block
CUSTOM_SYNTAX_MARKER_BLOCK |
// If the last symbol is `;` or `}`, it is self-terminating
KEYWORD_SEMICOLON | KEYWORD_CLOSE_BRACE
);
Ok(Expr::Custom(
crate::ast::CustomExpr {
inputs,
tokens,
state: user_state,
scope_may_be_changed: syntax.scope_may_be_changed,
self_terminated,
}
.into(),
pos,
))
}
/// Parse an expression.
fn parse_expr(
&self,
input: &mut TokenStream,
state: &mut ParseState,
lib: &mut FnLib,
settings: ParseSettings,
) -> ParseResult<Expr> {
#[cfg(not(feature = "unchecked"))]
settings.ensure_level_within_max_limit(state.max_expr_depth)?;
let mut settings = settings;
settings.pos = input.peek().expect(NEVER_ENDS).1;
// Parse expression normally.
let precedence = Precedence::new(1);
let lhs = self.parse_unary(input, state, lib, settings.level_up())?;
self.parse_binary_op(input, state, lib, precedence, lhs, settings.level_up())
}
/// Parse an if statement.
fn parse_if(
&self,
input: &mut TokenStream,
state: &mut ParseState,
lib: &mut FnLib,
settings: ParseSettings,
) -> ParseResult<Stmt> {
#[cfg(not(feature = "unchecked"))]
settings.ensure_level_within_max_limit(state.max_expr_depth)?;
// if ...
let mut settings = settings;
settings.pos = eat_token(input, Token::If);
// if guard { if_body }
ensure_not_statement_expr(input, "a boolean")?;
let guard = self
.parse_expr(input, state, lib, settings.level_up())?
.ensure_bool_expr()?;
ensure_not_assignment(input)?;
let if_body = self.parse_block(input, state, lib, settings.level_up())?;
// if guard { if_body } else ...
let else_body = if match_token(input, Token::Else).0 {
if let (Token::If, ..) = input.peek().expect(NEVER_ENDS) {
// if guard { if_body } else if ...
self.parse_if(input, state, lib, settings.level_up())?
} else {
// if guard { if_body } else { else-body }
self.parse_block(input, state, lib, settings.level_up())?
}
} else {
Stmt::Noop(Position::NONE)
};
Ok(Stmt::If(
(guard, if_body.into(), else_body.into()).into(),
settings.pos,
))
}
/// Parse a while loop.
fn parse_while_loop(
&self,
input: &mut TokenStream,
state: &mut ParseState,
lib: &mut FnLib,
settings: ParseSettings,
) -> ParseResult<Stmt> {
#[cfg(not(feature = "unchecked"))]
settings.ensure_level_within_max_limit(state.max_expr_depth)?;
let mut settings = settings;
// while|loops ...
let (guard, token_pos) = match input.next().expect(NEVER_ENDS) {
(Token::While, pos) => {
ensure_not_statement_expr(input, "a boolean")?;
let expr = self
.parse_expr(input, state, lib, settings.level_up())?
.ensure_bool_expr()?;
ensure_not_assignment(input)?;
(expr, pos)
}
(Token::Loop, pos) => (Expr::Unit(Position::NONE), pos),
token => unreachable!("Token::While or Token::Loop expected but gets {:?}", token),
};
settings.pos = token_pos;
settings.is_breakable = true;
let body = self.parse_block(input, state, lib, settings.level_up())?;
Ok(Stmt::While((guard, body.into()).into(), settings.pos))
}
/// Parse a do loop.
fn parse_do(
&self,
input: &mut TokenStream,
state: &mut ParseState,
lib: &mut FnLib,
settings: ParseSettings,
) -> ParseResult<Stmt> {
#[cfg(not(feature = "unchecked"))]
settings.ensure_level_within_max_limit(state.max_expr_depth)?;
// do ...
let mut settings = settings;
settings.pos = eat_token(input, Token::Do);
// do { body } [while|until] guard
settings.is_breakable = true;
let body = self.parse_block(input, state, lib, settings.level_up())?;
let negated = match input.next().expect(NEVER_ENDS) {
(Token::While, ..) => ASTFlags::NONE,
(Token::Until, ..) => ASTFlags::NEGATED,
(.., pos) => {
return Err(
PERR::MissingToken(Token::While.into(), "for the do statement".into())
.into_err(pos),
)
}
};
settings.is_breakable = false;
ensure_not_statement_expr(input, "a boolean")?;
let guard = self
.parse_expr(input, state, lib, settings.level_up())?
.ensure_bool_expr()?;
ensure_not_assignment(input)?;
Ok(Stmt::Do((guard, body.into()).into(), negated, settings.pos))
}
/// Parse a for loop.
fn parse_for(
&self,
input: &mut TokenStream,
state: &mut ParseState,
lib: &mut FnLib,
settings: ParseSettings,
) -> ParseResult<Stmt> {
#[cfg(not(feature = "unchecked"))]
settings.ensure_level_within_max_limit(state.max_expr_depth)?;
// for ...
let mut settings = settings;
settings.pos = eat_token(input, Token::For);
// for name ...
let (name, name_pos, counter_name, counter_pos) = if match_token(input, Token::LeftParen).0
{
// ( name, counter )
let (name, name_pos) = parse_var_name(input)?;
let (has_comma, pos) = match_token(input, Token::Comma);
if !has_comma {
return Err(PERR::MissingToken(
Token::Comma.into(),
"after the iteration variable name".into(),
)
.into_err(pos));
}
let (counter_name, counter_pos) = parse_var_name(input)?;
if counter_name == name {
return Err(
PERR::DuplicatedVariable(counter_name.to_string()).into_err(counter_pos)
);
}
let (has_close_paren, pos) = match_token(input, Token::RightParen);
if !has_close_paren {
return Err(PERR::MissingToken(
Token::RightParen.into(),
"to close the iteration variable".into(),
)
.into_err(pos));
}
(name, name_pos, counter_name, counter_pos)
} else {
// name
let (name, name_pos) = parse_var_name(input)?;
(name, name_pos, Identifier::new_const(), Position::NONE)
};
// for name in ...
match input.next().expect(NEVER_ENDS) {
(Token::In, ..) => (),
(Token::LexError(err), pos) => return Err(err.into_err(pos)),
(.., pos) => {
return Err(PERR::MissingToken(
Token::In.into(),
"after the iteration variable".into(),
)
.into_err(pos))
}
}
// for name in expr { body }
ensure_not_statement_expr(input, "a boolean")?;
let expr = self
.parse_expr(input, state, lib, settings.level_up())?
.ensure_iterable()?;
let prev_stack_len = state.stack.len();
if !counter_name.is_empty() {
state.stack.push(name.clone(), ());
}
let counter_var = Ident {
name: state.get_interned_string(counter_name),
pos: counter_pos,
};
let loop_var = state.get_interned_string(name);
state.stack.push(loop_var.clone(), ());
let loop_var = Ident {
name: loop_var,
pos: name_pos,
};
settings.is_breakable = true;
let body = self.parse_block(input, state, lib, settings.level_up())?;
state.stack.rewind(prev_stack_len);
Ok(Stmt::For(
Box::new((loop_var, counter_var, expr, body.into())),
settings.pos,
))
}
/// Parse a variable definition statement.
fn parse_let(
&self,
input: &mut TokenStream,
state: &mut ParseState,
lib: &mut FnLib,
access: AccessMode,
is_export: bool,
settings: ParseSettings,
) -> ParseResult<Stmt> {
#[cfg(not(feature = "unchecked"))]
settings.ensure_level_within_max_limit(state.max_expr_depth)?;
// let/const... (specified in `var_type`)
let mut settings = settings;
settings.pos = input.next().expect(NEVER_ENDS).1;
// let name ...
let (name, pos) = parse_var_name(input)?;
if !self.allow_shadowing() && state.stack.iter().any(|(v, ..)| v == name) {
return Err(PERR::VariableExists(name.to_string()).into_err(pos));
}
if let Some(ref filter) = self.def_var_filter {
let will_shadow = state.stack.iter().any(|(v, ..)| v == name);
let level = settings.level;
let is_const = access == AccessMode::ReadOnly;
let info = VarDefInfo {
name: &name,
is_const,
nesting_level: level,
will_shadow,
};
let mut this_ptr = None;
let context = EvalContext::new(
self,
&mut state.stack,
&mut state.global,
None,
&[],
&mut this_ptr,
level,
);
match filter(false, info, context) {
Ok(true) => (),
Ok(false) => return Err(PERR::ForbiddenVariable(name.to_string()).into_err(pos)),
Err(err) => match *err {
EvalAltResult::ErrorParsing(e, pos) => return Err(e.into_err(pos)),
_ => return Err(PERR::ForbiddenVariable(name.to_string()).into_err(pos)),
},
}
}
let name = state.get_interned_string(name);
// let name = ...
let expr = if match_token(input, Token::Equals).0 {
// let name = expr
self.parse_expr(input, state, lib, settings.level_up())?
} else {
Expr::Unit(Position::NONE)
};
let export = if is_export {
ASTFlags::EXPORTED
} else {
ASTFlags::NONE
};
let (existing, hit_barrier) = state.find_var(&name);
let existing = if !hit_barrier && existing > 0 {
let offset = state.stack.len() - existing;
if offset < state.block_stack_len {
// Defined in parent block
None
} else {
Some(offset)
}
} else {
None
};
let idx = if let Some(n) = existing {
state.stack.get_mut_by_index(n).set_access_mode(access);
Some(NonZeroUsize::new(state.stack.len() - n).unwrap())
} else {
state.stack.push_entry(name.as_str(), access, Dynamic::UNIT);
None
};
let var_def = (Ident { name, pos }, expr, idx).into();
Ok(match access {
// let name = expr
AccessMode::ReadWrite => Stmt::Var(var_def, export, settings.pos),
// const name = { expr:constant }
AccessMode::ReadOnly => Stmt::Var(var_def, ASTFlags::CONSTANT | export, settings.pos),
})
}
/// Parse an import statement.
#[cfg(not(feature = "no_module"))]
fn parse_import(
&self,
input: &mut TokenStream,
state: &mut ParseState,
lib: &mut FnLib,
settings: ParseSettings,
) -> ParseResult<Stmt> {
#[cfg(not(feature = "unchecked"))]
settings.ensure_level_within_max_limit(state.max_expr_depth)?;
// import ...
let mut settings = settings;
settings.pos = eat_token(input, Token::Import);
// import expr ...
let expr = self.parse_expr(input, state, lib, settings.level_up())?;
// import expr;
if !match_token(input, Token::As).0 {
let empty = Ident {
name: state.get_interned_string(""),
pos: Position::NONE,
};
return Ok(Stmt::Import((expr, empty).into(), settings.pos));
}
// import expr as name ...
let (name, pos) = parse_var_name(input)?;
let name = state.get_interned_string(name);
state.imports.push(name.clone());
Ok(Stmt::Import(
(expr, Ident { name, pos }).into(),
settings.pos,
))
}
/// Parse an export statement.
#[cfg(not(feature = "no_module"))]
fn parse_export(
&self,
input: &mut TokenStream,
state: &mut ParseState,
lib: &mut FnLib,
settings: ParseSettings,
) -> ParseResult<Stmt> {
#[cfg(not(feature = "unchecked"))]
settings.ensure_level_within_max_limit(state.max_expr_depth)?;
let mut settings = settings;
settings.pos = eat_token(input, Token::Export);
match input.peek().expect(NEVER_ENDS) {
(Token::Let, pos) => {
let pos = *pos;
let mut stmt =
self.parse_let(input, state, lib, AccessMode::ReadWrite, true, settings)?;
stmt.set_position(pos);
return Ok(stmt);
}
(Token::Const, pos) => {
let pos = *pos;
let mut stmt =
self.parse_let(input, state, lib, AccessMode::ReadOnly, true, settings)?;
stmt.set_position(pos);
return Ok(stmt);
}
_ => (),
}
let (id, id_pos) = parse_var_name(input)?;
let (alias, alias_pos) = if match_token(input, Token::As).0 {
let (name, pos) = parse_var_name(input)?;
(Some(name), pos)
} else {
(None, Position::NONE)
};
let export = (
Ident {
name: state.get_interned_string(id),
pos: id_pos,
},
Ident {
name: state.get_interned_string(alias.as_ref().map_or("", <_>::as_ref)),
pos: alias_pos,
},
);
Ok(Stmt::Export(export.into(), settings.pos))
}
/// Parse a statement block.
fn parse_block(
&self,
input: &mut TokenStream,
state: &mut ParseState,
lib: &mut FnLib,
settings: ParseSettings,
) -> ParseResult<Stmt> {
#[cfg(not(feature = "unchecked"))]
settings.ensure_level_within_max_limit(state.max_expr_depth)?;
// Must start with {
let mut settings = settings;
settings.pos = match input.next().expect(NEVER_ENDS) {
(Token::LeftBrace, pos) => pos,
(Token::LexError(err), pos) => return Err(err.into_err(pos)),
(.., pos) => {
return Err(PERR::MissingToken(
Token::LeftBrace.into(),
"to start a statement block".into(),
)
.into_err(pos))
}
};
let mut statements = StaticVec::new_const();
if !settings.allow_statements {
let stmt = self.parse_expr_stmt(input, state, lib, settings.level_up())?;
statements.push(stmt);
// Must end with }
return match input.next().expect(NEVER_ENDS) {
(Token::RightBrace, pos) => Ok((statements, settings.pos, pos).into()),
(Token::LexError(err), pos) => Err(err.into_err(pos)),
(.., pos) => Err(PERR::MissingToken(
Token::LeftBrace.into(),
"to start a statement block".into(),
)
.into_err(pos)),
};
}
let prev_entry_stack_len = state.block_stack_len;
state.block_stack_len = state.stack.len();
#[cfg(not(feature = "no_module"))]
let orig_imports_len = state.imports.len();
let end_pos = loop {
// Terminated?
match input.peek().expect(NEVER_ENDS) {
(Token::RightBrace, ..) => break eat_token(input, Token::RightBrace),
(Token::EOF, pos) => {
return Err(PERR::MissingToken(
Token::RightBrace.into(),
"to terminate this block".into(),
)
.into_err(*pos));
}
_ => (),
}
// Parse statements inside the block
settings.at_global_level = false;
let stmt = self.parse_stmt(input, state, lib, settings.level_up())?;
if stmt.is_noop() {
continue;
}
// See if it needs a terminating semicolon
let need_semicolon = !stmt.is_self_terminated();
statements.push(stmt);
match input.peek().expect(NEVER_ENDS) {
// { ... stmt }
(Token::RightBrace, ..) => break eat_token(input, Token::RightBrace),
// { ... stmt;
(Token::SemiColon, ..) if need_semicolon => {
eat_token(input, Token::SemiColon);
}
// { ... { stmt } ;
(Token::SemiColon, ..) if !need_semicolon => {
eat_token(input, Token::SemiColon);
}
// { ... { stmt } ???
_ if !need_semicolon => (),
// { ... stmt <error>
(Token::LexError(err), err_pos) => return Err(err.clone().into_err(*err_pos)),
// { ... stmt ???
(.., pos) => {
// Semicolons are not optional between statements
return Err(PERR::MissingToken(
Token::SemiColon.into(),
"to terminate this statement".into(),
)
.into_err(*pos));
}
}
};
state.stack.rewind(state.block_stack_len);
state.block_stack_len = prev_entry_stack_len;
#[cfg(not(feature = "no_module"))]
state.imports.truncate(orig_imports_len);
Ok((statements, settings.pos, end_pos).into())
}
/// Parse an expression as a statement.
fn parse_expr_stmt(
&self,
input: &mut TokenStream,
state: &mut ParseState,
lib: &mut FnLib,
settings: ParseSettings,
) -> ParseResult<Stmt> {
#[cfg(not(feature = "unchecked"))]
settings.ensure_level_within_max_limit(state.max_expr_depth)?;
let mut settings = settings;
settings.pos = input.peek().expect(NEVER_ENDS).1;
let expr = self.parse_expr(input, state, lib, settings.level_up())?;
let stmt = self.parse_op_assignment_stmt(input, state, lib, expr, settings.level_up())?;
Ok(stmt)
}
/// Parse a single statement.
fn parse_stmt(
&self,
input: &mut TokenStream,
state: &mut ParseState,
lib: &mut FnLib,
settings: ParseSettings,
) -> ParseResult<Stmt> {
use AccessMode::{ReadOnly, ReadWrite};
let mut settings = settings;
#[cfg(not(feature = "no_function"))]
#[cfg(feature = "metadata")]
let comments = {
let mut comments = StaticVec::<SmartString>::new();
let mut comments_pos = Position::NONE;
// Handle doc-comments.
while let (Token::Comment(ref comment), pos) = input.peek().expect(NEVER_ENDS) {
if comments_pos.is_none() {
comments_pos = *pos;
}
if !crate::tokenizer::is_doc_comment(comment) {
unreachable!("doc-comment expected but gets {:?}", comment);
}
if !settings.at_global_level {
return Err(PERR::WrongDocComment.into_err(comments_pos));
}
match input.next().expect(NEVER_ENDS).0 {
Token::Comment(comment) => {
comments.push(comment);
match input.peek().expect(NEVER_ENDS) {
(Token::Fn | Token::Private, ..) => break,
(Token::Comment(..), ..) => (),
_ => return Err(PERR::WrongDocComment.into_err(comments_pos)),
}
}
token => unreachable!("Token::Comment expected but gets {:?}", token),
}
}
comments
};
let (token, token_pos) = match input.peek().expect(NEVER_ENDS) {
(Token::EOF, pos) => return Ok(Stmt::Noop(*pos)),
(x, pos) => (x, *pos),
};
settings.pos = token_pos;
#[cfg(not(feature = "unchecked"))]
settings.ensure_level_within_max_limit(state.max_expr_depth)?;
match token {
// ; - empty statement
Token::SemiColon => {
eat_token(input, Token::SemiColon);
Ok(Stmt::Noop(token_pos))
}
// { - statements block
Token::LeftBrace => Ok(self.parse_block(input, state, lib, settings.level_up())?),
// fn ...
#[cfg(not(feature = "no_function"))]
Token::Fn if !settings.at_global_level => {
Err(PERR::WrongFnDefinition.into_err(token_pos))
}
#[cfg(not(feature = "no_function"))]
Token::Fn | Token::Private => {
let access = if matches!(token, Token::Private) {
eat_token(input, Token::Private);
crate::FnAccess::Private
} else {
crate::FnAccess::Public
};
match input.next().expect(NEVER_ENDS) {
(Token::Fn, pos) => {
// Build new parse state
let interned_strings = std::mem::take(&mut state.interned_strings);
let mut new_state = ParseState::new(
self,
state.scope,
interned_strings,
state.tokenizer_control.clone(),
);
#[cfg(not(feature = "no_module"))]
{
// Do not allow storing an index to a globally-imported module
// just in case the function is separated from this `AST`.
//
// Keep them in `global_imports` instead so that strict variables
// mode will not complain.
new_state.global_imports.clone_from(&state.global_imports);
new_state
.global_imports
.extend(state.imports.iter().cloned());
}
#[cfg(not(feature = "unchecked"))]
{
new_state.max_expr_depth = self.max_function_expr_depth();
}
let mut options = self.options;
options.set(
LangOptions::STRICT_VAR,
settings.options.contains(LangOptions::STRICT_VAR),
);
let new_settings = ParseSettings {
at_global_level: false,
in_fn_scope: true,
#[cfg(not(feature = "no_closure"))]
in_closure: false,
is_breakable: false,
allow_statements: true,
level: 0,
options,
pos,
};
let func = self.parse_fn(
input,
&mut new_state,
lib,
access,
new_settings,
#[cfg(not(feature = "no_function"))]
#[cfg(feature = "metadata")]
comments,
);
// Restore parse state
state.interned_strings = new_state.interned_strings;
let func = func?;
let hash = calc_fn_hash(None, &func.name, func.params.len());
if !lib.is_empty() && lib.contains_key(&hash) {
return Err(PERR::FnDuplicatedDefinition(
func.name.to_string(),
func.params.len(),
)
.into_err(pos));
}
lib.insert(hash, func.into());
Ok(Stmt::Noop(pos))
}
(.., pos) => Err(PERR::MissingToken(
Token::Fn.into(),
format!("following '{}'", Token::Private.syntax()),
)
.into_err(pos)),
}
}
Token::If => self.parse_if(input, state, lib, settings.level_up()),
Token::Switch => self.parse_switch(input, state, lib, settings.level_up()),
Token::While | Token::Loop if self.allow_looping() => {
self.parse_while_loop(input, state, lib, settings.level_up())
}
Token::Do if self.allow_looping() => {
self.parse_do(input, state, lib, settings.level_up())
}
Token::For if self.allow_looping() => {
self.parse_for(input, state, lib, settings.level_up())
}
Token::Continue if self.allow_looping() && settings.is_breakable => {
let pos = eat_token(input, Token::Continue);
Ok(Stmt::BreakLoop(ASTFlags::NONE, pos))
}
Token::Break if self.allow_looping() && settings.is_breakable => {
let pos = eat_token(input, Token::Break);
Ok(Stmt::BreakLoop(ASTFlags::BREAK, pos))
}
Token::Continue | Token::Break if self.allow_looping() => {
Err(PERR::LoopBreak.into_err(token_pos))
}
Token::Return | Token::Throw => {
let (return_type, token_pos) = input
.next()
.map(|(token, pos)| {
let flags = match token {
Token::Return => ASTFlags::NONE,
Token::Throw => ASTFlags::BREAK,
token => unreachable!(
"Token::Return or Token::Throw expected but gets {:?}",
token
),
};
(flags, pos)
})
.expect(NEVER_ENDS);
match input.peek().expect(NEVER_ENDS) {
// `return`/`throw` at <EOF>
(Token::EOF, ..) => Ok(Stmt::Return(None, return_type, token_pos)),
// `return`/`throw` at end of block
(Token::RightBrace, ..) if !settings.at_global_level => {
Ok(Stmt::Return(None, return_type, token_pos))
}
// `return;` or `throw;`
(Token::SemiColon, ..) => Ok(Stmt::Return(None, return_type, token_pos)),
// `return` or `throw` with expression
_ => {
let expr = self.parse_expr(input, state, lib, settings.level_up())?;
Ok(Stmt::Return(Some(expr.into()), return_type, token_pos))
}
}
}
Token::Try => self.parse_try_catch(input, state, lib, settings.level_up()),
Token::Let => self.parse_let(input, state, lib, ReadWrite, false, settings.level_up()),
Token::Const => self.parse_let(input, state, lib, ReadOnly, false, settings.level_up()),
#[cfg(not(feature = "no_module"))]
Token::Import => self.parse_import(input, state, lib, settings.level_up()),
#[cfg(not(feature = "no_module"))]
Token::Export if !settings.at_global_level => {
Err(PERR::WrongExport.into_err(token_pos))
}
#[cfg(not(feature = "no_module"))]
Token::Export => self.parse_export(input, state, lib, settings.level_up()),
_ => self.parse_expr_stmt(input, state, lib, settings.level_up()),
}
}
/// Parse a try/catch statement.
fn parse_try_catch(
&self,
input: &mut TokenStream,
state: &mut ParseState,
lib: &mut FnLib,
settings: ParseSettings,
) -> ParseResult<Stmt> {
#[cfg(not(feature = "unchecked"))]
settings.ensure_level_within_max_limit(state.max_expr_depth)?;
// try ...
let mut settings = settings;
settings.pos = eat_token(input, Token::Try);
// try { try_block }
let try_block = self.parse_block(input, state, lib, settings.level_up())?;
// try { try_block } catch
let (matched, catch_pos) = match_token(input, Token::Catch);
if !matched {
return Err(
PERR::MissingToken(Token::Catch.into(), "for the 'try' statement".into())
.into_err(catch_pos),
);
}
// try { try_block } catch (
let catch_var = if match_token(input, Token::LeftParen).0 {
let (name, pos) = parse_var_name(input)?;
let (matched, err_pos) = match_token(input, Token::RightParen);
if !matched {
return Err(PERR::MissingToken(
Token::RightParen.into(),
"to enclose the catch variable".into(),
)
.into_err(err_pos));
}
let name = state.get_interned_string(name);
state.stack.push(name.clone(), ());
Ident { name, pos }
} else {
Ident {
name: state.get_interned_string(""),
pos: Position::NONE,
}
};
// try { try_block } catch ( var ) { catch_block }
let catch_block = self.parse_block(input, state, lib, settings.level_up())?;
if !catch_var.is_empty() {
// Remove the error variable from the stack
state.stack.rewind(state.stack.len() - 1);
}
Ok(Stmt::TryCatch(
TryCatchBlock {
try_block: try_block.into(),
catch_var,
catch_block: catch_block.into(),
}
.into(),
settings.pos,
))
}
/// Parse a function definition.
#[cfg(not(feature = "no_function"))]
fn parse_fn(
&self,
input: &mut TokenStream,
state: &mut ParseState,
lib: &mut FnLib,
access: crate::FnAccess,
settings: ParseSettings,
#[cfg(not(feature = "no_function"))]
#[cfg(feature = "metadata")]
comments: StaticVec<SmartString>,
) -> ParseResult<ScriptFnDef> {
#[cfg(not(feature = "unchecked"))]
settings.ensure_level_within_max_limit(state.max_expr_depth)?;
let mut settings = settings;
let (token, pos) = input.next().expect(NEVER_ENDS);
let name = match token.into_function_name_for_override() {
Ok(r) => r,
Err(Token::Reserved(s)) => return Err(PERR::Reserved(s.to_string()).into_err(pos)),
Err(_) => return Err(PERR::FnMissingName.into_err(pos)),
};
let no_params = match input.peek().expect(NEVER_ENDS) {
(Token::LeftParen, ..) => {
eat_token(input, Token::LeftParen);
match_token(input, Token::RightParen).0
}
(Token::Unit, ..) => {
eat_token(input, Token::Unit);
true
}
(.., pos) => return Err(PERR::FnMissingParams(name.to_string()).into_err(*pos)),
};
let mut params = StaticVec::<(ImmutableString, _)>::new_const();
if !no_params {
let sep_err = format!("to separate the parameters of function '{name}'");
loop {
match input.next().expect(NEVER_ENDS) {
(Token::RightParen, ..) => break,
(Token::Identifier(s), pos) => {
if params.iter().any(|(p, _)| p.as_str() == &*s) {
return Err(PERR::FnDuplicatedParam(name.to_string(), s.to_string())
.into_err(pos));
}
let s = state.get_interned_string(s);
state.stack.push(s.clone(), ());
params.push((s, pos));
}
(Token::LexError(err), pos) => return Err(err.into_err(pos)),
(.., pos) => {
return Err(PERR::MissingToken(
Token::RightParen.into(),
format!("to close the parameters list of function '{name}'"),
)
.into_err(pos))
}
}
match input.next().expect(NEVER_ENDS) {
(Token::RightParen, ..) => break,
(Token::Comma, ..) => (),
(Token::LexError(err), pos) => return Err(err.into_err(pos)),
(.., pos) => {
return Err(PERR::MissingToken(Token::Comma.into(), sep_err).into_err(pos))
}
}
}
}
// Parse function body
let body = match input.peek().expect(NEVER_ENDS) {
(Token::LeftBrace, ..) => {
settings.is_breakable = false;
self.parse_block(input, state, lib, settings.level_up())?
}
(.., pos) => return Err(PERR::FnMissingBody(name.to_string()).into_err(*pos)),
}
.into();
let mut params: StaticVec<_> = params.into_iter().map(|(p, ..)| p).collect();
params.shrink_to_fit();
Ok(ScriptFnDef {
name: state.get_interned_string(name),
access,
params,
body,
#[cfg(not(feature = "no_module"))]
environ: None,
#[cfg(not(feature = "no_function"))]
#[cfg(feature = "metadata")]
comments: comments
.into_iter()
.map(|s| s.to_string().into_boxed_str())
.collect::<Vec<_>>()
.into_boxed_slice(),
})
}
/// Creates a curried expression from a list of external variables
#[cfg(not(feature = "no_function"))]
#[cfg(not(feature = "no_closure"))]
fn make_curry_from_externals(
state: &mut ParseState,
fn_expr: Expr,
externals: StaticVec<crate::ast::Ident>,
pos: Position,
) -> Expr {
// If there are no captured variables, no need to curry
if externals.is_empty() {
return fn_expr;
}
let num_externals = externals.len();
let mut args = StaticVec::with_capacity(externals.len() + 1);
args.push(fn_expr);
args.extend(
externals
.iter()
.cloned()
.map(|crate::ast::Ident { name, pos }| {
#[cfg(not(feature = "no_module"))]
let ns = crate::ast::Namespace::NONE;
#[cfg(feature = "no_module")]
let ns = ();
Expr::Variable((None, ns, 0, name).into(), None, pos)
}),
);
let expr = FnCallExpr {
name: state.get_interned_string(crate::engine::KEYWORD_FN_PTR_CURRY),
hashes: FnCallHashes::from_native(calc_fn_hash(
None,
crate::engine::KEYWORD_FN_PTR_CURRY,
num_externals + 1,
)),
args,
pos,
..Default::default()
}
.into_fn_call_expr(pos);
// Convert the entire expression into a statement block, then insert the relevant
// [`Share`][Stmt::Share] statements.
let mut statements = StaticVec::with_capacity(externals.len() + 1);
statements.extend(
externals
.into_iter()
.map(|crate::ast::Ident { name, pos }| Stmt::Share(name, pos)),
);
statements.push(Stmt::Expr(expr.into()));
Expr::Stmt(crate::ast::StmtBlock::new(statements, pos, Position::NONE).into())
}
/// Parse an anonymous function definition.
#[cfg(not(feature = "no_function"))]
fn parse_anon_fn(
&self,
input: &mut TokenStream,
state: &mut ParseState,
lib: &mut FnLib,
settings: ParseSettings,
) -> ParseResult<(Expr, ScriptFnDef)> {
#[cfg(not(feature = "unchecked"))]
settings.ensure_level_within_max_limit(state.max_expr_depth)?;
let mut settings = settings;
let mut params_list = StaticVec::<ImmutableString>::new_const();
if input.next().expect(NEVER_ENDS).0 != Token::Or && !match_token(input, Token::Pipe).0 {
loop {
match input.next().expect(NEVER_ENDS) {
(Token::Pipe, ..) => break,
(Token::Identifier(s), pos) => {
if params_list.iter().any(|p| p.as_str() == &*s) {
return Err(
PERR::FnDuplicatedParam(String::new(), s.to_string()).into_err(pos)
);
}
let s = state.get_interned_string(s);
state.stack.push(s.clone(), ());
params_list.push(s);
}
(Token::LexError(err), pos) => return Err(err.into_err(pos)),
(.., pos) => {
return Err(PERR::MissingToken(
Token::Pipe.into(),
"to close the parameters list of anonymous function".into(),
)
.into_err(pos))
}
}
match input.next().expect(NEVER_ENDS) {
(Token::Pipe, ..) => break,
(Token::Comma, ..) => (),
(Token::LexError(err), pos) => return Err(err.into_err(pos)),
(.., pos) => {
return Err(PERR::MissingToken(
Token::Comma.into(),
"to separate the parameters of anonymous function".into(),
)
.into_err(pos))
}
}
}
}
// Parse function body
settings.is_breakable = false;
let body = self.parse_stmt(input, state, lib, settings.level_up())?;
// External variables may need to be processed in a consistent order,
// so extract them into a list.
#[cfg(not(feature = "no_closure"))]
let (mut params, externals) = {
let externals: StaticVec<_> = state.external_vars.iter().cloned().collect();
let mut params = StaticVec::with_capacity(params_list.len() + externals.len());
params.extend(
externals
.iter()
.map(|crate::ast::Ident { name, .. }| name.clone()),
);
(params, externals)
};
#[cfg(feature = "no_closure")]
let mut params = StaticVec::with_capacity(params_list.len());
params.append(&mut params_list);
// Create unique function name by hashing the script body plus the parameters.
let hasher = &mut get_hasher();
params.iter().for_each(|p| p.hash(hasher));
body.hash(hasher);
let hash = hasher.finish();
let fn_name = state.get_interned_string(make_anonymous_fn(hash));
// Define the function
let script = ScriptFnDef {
name: fn_name.clone(),
access: crate::FnAccess::Public,
params,
body: body.into(),
#[cfg(not(feature = "no_module"))]
environ: None,
#[cfg(not(feature = "no_function"))]
#[cfg(feature = "metadata")]
comments: Box::default(),
};
let fn_ptr = crate::FnPtr::new_unchecked(fn_name, StaticVec::new_const());
let expr = Expr::DynamicConstant(Box::new(fn_ptr.into()), settings.pos);
#[cfg(not(feature = "no_closure"))]
let expr = Self::make_curry_from_externals(state, expr, externals, settings.pos);
Ok((expr, script))
}
/// Parse a global level expression.
pub(crate) fn parse_global_expr(
&self,
input: &mut TokenStream,
state: &mut ParseState,
_optimization_level: OptimizationLevel,
) -> ParseResult<AST> {
let mut functions = StraightHashMap::default();
let mut options = self.options;
options.remove(LangOptions::STMT_EXPR);
#[cfg(not(feature = "no_function"))]
options.remove(LangOptions::ANON_FN);
let settings = ParseSettings {
at_global_level: true,
#[cfg(not(feature = "no_function"))]
in_fn_scope: false,
#[cfg(not(feature = "no_function"))]
#[cfg(not(feature = "no_closure"))]
in_closure: false,
is_breakable: false,
allow_statements: false,
level: 0,
options,
pos: Position::NONE,
};
let expr = self.parse_expr(input, state, &mut functions, settings)?;
assert!(functions.is_empty());
match input.peek().expect(NEVER_ENDS) {
(Token::EOF, ..) => (),
// Return error if the expression doesn't end
(token, pos) => {
return Err(LexError::UnexpectedInput(token.syntax().to_string()).into_err(*pos))
}
}
let mut statements = StmtBlockContainer::new_const();
statements.push(Stmt::Expr(expr.into()));
#[cfg(not(feature = "no_optimize"))]
return Ok(crate::optimizer::optimize_into_ast(
self,
state.scope,
statements,
#[cfg(not(feature = "no_function"))]
StaticVec::new_const(),
_optimization_level,
));
#[cfg(feature = "no_optimize")]
return Ok(AST::new(
statements,
#[cfg(not(feature = "no_function"))]
crate::Module::new(),
));
}
/// Parse the global level statements.
fn parse_global_level(
&self,
input: &mut TokenStream,
state: &mut ParseState,
) -> ParseResult<(StmtBlockContainer, StaticVec<Shared<ScriptFnDef>>)> {
let mut statements = StmtBlockContainer::new_const();
let mut functions = StraightHashMap::default();
while !input.peek().expect(NEVER_ENDS).0.is_eof() {
let settings = ParseSettings {
at_global_level: true,
#[cfg(not(feature = "no_function"))]
in_fn_scope: false,
#[cfg(not(feature = "no_function"))]
#[cfg(not(feature = "no_closure"))]
in_closure: false,
is_breakable: false,
allow_statements: true,
options: self.options,
level: 0,
pos: Position::NONE,
};
let stmt = self.parse_stmt(input, state, &mut functions, settings)?;
if stmt.is_noop() {
continue;
}
let need_semicolon = !stmt.is_self_terminated();
statements.push(stmt);
match input.peek().expect(NEVER_ENDS) {
// EOF
(Token::EOF, ..) => break,
// stmt ;
(Token::SemiColon, ..) if need_semicolon => {
eat_token(input, Token::SemiColon);
}
// stmt ;
(Token::SemiColon, ..) if !need_semicolon => (),
// { stmt } ???
_ if !need_semicolon => (),
// stmt <error>
(Token::LexError(err), pos) => return Err(err.clone().into_err(*pos)),
// stmt ???
(.., pos) => {
// Semicolons are not optional between statements
return Err(PERR::MissingToken(
Token::SemiColon.into(),
"to terminate this statement".into(),
)
.into_err(*pos));
}
}
}
Ok((statements, functions.into_iter().map(|(.., v)| v).collect()))
}
/// Run the parser on an input stream, returning an AST.
#[inline]
pub(crate) fn parse(
&self,
input: &mut TokenStream,
state: &mut ParseState,
_optimization_level: OptimizationLevel,
) -> ParseResult<AST> {
let (statements, _lib) = self.parse_global_level(input, state)?;
#[cfg(not(feature = "no_optimize"))]
return Ok(crate::optimizer::optimize_into_ast(
self,
state.scope,
statements,
#[cfg(not(feature = "no_function"))]
_lib,
_optimization_level,
));
#[cfg(feature = "no_optimize")]
#[cfg(not(feature = "no_function"))]
{
let mut m = crate::Module::new();
for fn_def in _lib {
m.set_script_fn(fn_def);
}
return Ok(AST::new(statements, m));
}
#[cfg(feature = "no_optimize")]
#[cfg(feature = "no_function")]
return Ok(AST::new(
statements,
#[cfg(not(feature = "no_function"))]
crate::Module::new(),
));
}
}
Reference in New Issue View Git Blame Copy Permalink