2568 lines
84 KiB
Rust
2568 lines
84 KiB
Rust
//! Main module defining the lexer and parser.
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use crate::any::{Any, AnyExt, Dynamic};
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use crate::engine::Engine;
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use crate::error::{LexError, ParseError, ParseErrorType};
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use crate::scope::{Scope, VariableType};
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#[cfg(not(feature = "no_optimize"))]
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use crate::optimize::optimize_into_ast;
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use crate::stdlib::{
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borrow::Cow,
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boxed::Box,
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char,
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cmp::Ordering,
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fmt, format,
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iter::Peekable,
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str::Chars,
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str::FromStr,
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string::{String, ToString},
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sync::Arc,
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usize, vec,
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vec::Vec,
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};
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/// The system integer type.
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///
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/// If the `only_i32` feature is enabled, this will be `i32` instead.
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#[cfg(not(feature = "only_i32"))]
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pub type INT = i64;
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/// The system integer type.
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///
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/// If the `only_i32` feature is not enabled, this will be `i64` instead.
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#[cfg(feature = "only_i32")]
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pub type INT = i32;
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/// The system floating-point type.
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#[cfg(not(feature = "no_float"))]
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pub type FLOAT = f64;
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type LERR = LexError;
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type PERR = ParseErrorType;
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/// A location (line number + character position) in the input script.
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#[derive(Eq, PartialEq, Ord, PartialOrd, Hash, Clone, Copy)]
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pub struct Position {
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/// Line number - 0 = none, MAX = EOF
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line: usize,
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/// Character position - 0 = BOL, MAX = EOF
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pos: usize,
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}
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impl Position {
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/// Create a new `Position`.
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pub fn new(line: usize, position: usize) -> Self {
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assert!(line != 0, "line cannot be zero");
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assert!(
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line != usize::MAX || position != usize::MAX,
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"invalid position"
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);
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Self {
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line,
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pos: position,
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}
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}
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/// Get the line number (1-based), or `None` if no position or EOF.
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pub fn line(&self) -> Option<usize> {
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if self.is_none() || self.is_eof() {
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None
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} else {
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Some(self.line)
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}
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}
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/// Get the character position (1-based), or `None` if at beginning of a line.
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pub fn position(&self) -> Option<usize> {
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if self.is_none() || self.is_eof() {
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None
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} else if self.pos == 0 {
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None
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} else {
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Some(self.pos)
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}
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}
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/// Advance by one character position.
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pub(crate) fn advance(&mut self) {
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self.pos += 1;
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}
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/// Go backwards by one character position.
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///
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/// # Panics
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///
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/// Panics if already at beginning of a line - cannot rewind to a previous line.
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///
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pub(crate) fn rewind(&mut self) {
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assert!(self.pos > 0, "cannot rewind at position 0");
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self.pos -= 1;
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}
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/// Advance to the next line.
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pub(crate) fn new_line(&mut self) {
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self.line += 1;
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self.pos = 0;
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}
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/// Create a `Position` representing no position.
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pub(crate) fn none() -> Self {
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Self { line: 0, pos: 0 }
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}
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/// Create a `Position` at EOF.
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pub(crate) fn eof() -> Self {
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Self {
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line: usize::MAX,
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pos: usize::MAX,
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}
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}
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/// Is there no `Position`?
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pub fn is_none(&self) -> bool {
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self.line == 0 && self.pos == 0
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}
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/// Is the `Position` at EOF?
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pub fn is_eof(&self) -> bool {
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self.line == usize::MAX && self.pos == usize::MAX
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}
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}
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impl Default for Position {
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fn default() -> Self {
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Self::new(1, 0)
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}
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}
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impl fmt::Display for Position {
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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if self.is_eof() {
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write!(f, "EOF")
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} else if self.is_none() {
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write!(f, "none")
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} else {
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write!(f, "line {}, position {}", self.line, self.pos)
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}
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}
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}
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impl fmt::Debug for Position {
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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if self.is_eof() {
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write!(f, "(EOF)")
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} else {
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write!(f, "({}:{})", self.line, self.pos)
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}
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}
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}
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/// Compiled AST (abstract syntax tree) of a Rhai script.
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#[derive(Debug, Clone)]
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pub struct AST(pub(crate) Vec<Stmt>, pub(crate) Vec<Arc<FnDef>>);
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/// A script-function definition.
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#[derive(Debug, Clone)]
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pub struct FnDef {
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/// Function name.
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pub name: String,
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/// Names of function parameters.
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pub params: Vec<String>,
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/// Function body.
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pub body: Stmt,
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/// Position of the function definition.
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pub pos: Position,
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}
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impl FnDef {
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/// Function to order two FnDef records, for binary search.
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pub fn compare(&self, name: &str, params_len: usize) -> Ordering {
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// First order by name
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match self.name.as_str().cmp(name) {
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// Then by number of parameters
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Ordering::Equal => self.params.len().cmp(¶ms_len),
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order => order,
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}
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}
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}
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/// `return`/`throw` statement.
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#[derive(Debug, PartialEq, Eq, Hash, Clone, Copy)]
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pub enum ReturnType {
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/// `return` statement.
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Return,
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/// `throw` statement.
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Exception,
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}
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/// A statement.
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#[derive(Debug, Clone)]
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pub enum Stmt {
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/// No-op.
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Noop(Position),
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/// if expr { stmt } else { stmt }
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IfThenElse(Box<Expr>, Box<Stmt>, Option<Box<Stmt>>),
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/// while expr { stmt }
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While(Box<Expr>, Box<Stmt>),
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/// loop { stmt }
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Loop(Box<Stmt>),
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/// for id in expr { stmt }
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For(String, Box<Expr>, Box<Stmt>),
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/// let id = expr
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Let(String, Option<Box<Expr>>, Position),
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/// const id = expr
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Const(String, Box<Expr>, Position),
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/// { stmt; ... }
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Block(Vec<Stmt>, Position),
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/// { stmt }
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Expr(Box<Expr>),
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/// break
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Break(Position),
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/// `return`/`throw`
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ReturnWithVal(Option<Box<Expr>>, ReturnType, Position),
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}
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impl Stmt {
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/// Get the `Position` of this statement.
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pub fn position(&self) -> Position {
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match self {
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Stmt::Noop(pos)
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| Stmt::Let(_, _, pos)
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| Stmt::Const(_, _, pos)
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| Stmt::Block(_, pos)
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| Stmt::Break(pos)
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| Stmt::ReturnWithVal(_, _, pos) => *pos,
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Stmt::IfThenElse(expr, _, _) | Stmt::Expr(expr) => expr.position(),
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Stmt::While(_, stmt) | Stmt::Loop(stmt) | Stmt::For(_, _, stmt) => stmt.position(),
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}
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}
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/// Is this statement self-terminated (i.e. no need for a semicolon terminator)?
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pub fn is_self_terminated(&self) -> bool {
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match self {
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Stmt::IfThenElse(_, _, _)
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| Stmt::While(_, _)
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| Stmt::Loop(_)
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| Stmt::For(_, _, _)
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| Stmt::Block(_, _) => true,
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// A No-op requires a semicolon in order to know it is an empty statement!
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Stmt::Noop(_) => false,
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Stmt::Let(_, _, _)
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| Stmt::Const(_, _, _)
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| Stmt::Expr(_)
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| Stmt::Break(_)
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| Stmt::ReturnWithVal(_, _, _) => false,
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}
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}
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/// Is this statement _pure_?
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pub fn is_pure(&self) -> bool {
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match self {
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Stmt::Noop(_) => true,
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Stmt::Expr(expr) => expr.is_pure(),
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Stmt::IfThenElse(guard, if_block, Some(else_block)) => {
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guard.is_pure() && if_block.is_pure() && else_block.is_pure()
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}
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Stmt::IfThenElse(guard, block, None) | Stmt::While(guard, block) => {
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guard.is_pure() && block.is_pure()
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}
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Stmt::Loop(block) => block.is_pure(),
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Stmt::For(_, range, block) => range.is_pure() && block.is_pure(),
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Stmt::Let(_, _, _) | Stmt::Const(_, _, _) => false,
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Stmt::Block(statements, _) => statements.iter().all(Stmt::is_pure),
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Stmt::Break(_) | Stmt::ReturnWithVal(_, _, _) => false,
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}
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}
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}
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/// An expression.
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#[derive(Debug, Clone)]
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pub enum Expr {
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/// Integer constant.
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IntegerConstant(INT, Position),
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/// Floating-point constant.
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#[cfg(not(feature = "no_float"))]
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FloatConstant(FLOAT, Position),
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/// Character constant.
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CharConstant(char, Position),
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/// String constant.
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StringConstant(String, Position),
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/// Variable access.
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Variable(String, Position),
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/// Property access.
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Property(String, Position),
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/// { stmt }
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Stmt(Box<Stmt>, Position),
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/// func(expr, ... )
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FunctionCall(String, Vec<Expr>, Option<Dynamic>, Position),
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/// expr = expr
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Assignment(Box<Expr>, Box<Expr>, Position),
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/// lhs.rhs
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Dot(Box<Expr>, Box<Expr>, Position),
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/// expr[expr]
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#[cfg(not(feature = "no_index"))]
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Index(Box<Expr>, Box<Expr>, Position),
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#[cfg(not(feature = "no_index"))]
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/// [ expr, ... ]
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Array(Vec<Expr>, Position),
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/// lhs && rhs
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And(Box<Expr>, Box<Expr>),
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/// lhs || rhs
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Or(Box<Expr>, Box<Expr>),
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/// true
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True(Position),
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/// false
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False(Position),
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/// ()
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Unit(Position),
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}
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impl Expr {
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/// Get the `Dynamic` value of a constant expression.
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///
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/// # Panics
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///
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/// Panics when the expression is not constant.
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pub fn get_constant_value(&self) -> Dynamic {
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match self {
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Expr::IntegerConstant(i, _) => i.into_dynamic(),
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Expr::CharConstant(c, _) => c.into_dynamic(),
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Expr::StringConstant(s, _) => s.into_dynamic(),
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Expr::True(_) => true.into_dynamic(),
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Expr::False(_) => false.into_dynamic(),
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Expr::Unit(_) => ().into_dynamic(),
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#[cfg(not(feature = "no_index"))]
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Expr::Array(items, _) if items.iter().all(Expr::is_constant) => items
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.iter()
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.map(Expr::get_constant_value)
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.collect::<Vec<_>>()
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.into_dynamic(),
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#[cfg(not(feature = "no_float"))]
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Expr::FloatConstant(f, _) => f.into_dynamic(),
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_ => panic!("cannot get value of non-constant expression"),
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}
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}
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/// Get the display value of a constant expression.
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///
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/// # Panics
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///
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/// Panics when the expression is not constant.
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pub fn get_constant_str(&self) -> String {
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match self {
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Expr::IntegerConstant(i, _) => i.to_string(),
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Expr::CharConstant(c, _) => c.to_string(),
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Expr::StringConstant(_, _) => "string".to_string(),
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Expr::True(_) => "true".to_string(),
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Expr::False(_) => "false".to_string(),
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Expr::Unit(_) => "()".to_string(),
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#[cfg(not(feature = "no_index"))]
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Expr::Array(items, _) if items.iter().all(Expr::is_constant) => "array".to_string(),
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#[cfg(not(feature = "no_float"))]
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Expr::FloatConstant(f, _) => f.to_string(),
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_ => panic!("cannot get value of non-constant expression"),
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}
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}
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/// Get the `Position` of the expression.
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pub fn position(&self) -> Position {
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match self {
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Expr::IntegerConstant(_, pos)
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| Expr::CharConstant(_, pos)
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| Expr::StringConstant(_, pos)
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| Expr::Variable(_, pos)
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| Expr::Property(_, pos)
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| Expr::Stmt(_, pos)
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| Expr::FunctionCall(_, _, _, pos)
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| Expr::True(pos)
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| Expr::False(pos)
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| Expr::Unit(pos) => *pos,
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Expr::Assignment(expr, _, _)
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| Expr::Dot(expr, _, _)
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| Expr::And(expr, _)
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| Expr::Or(expr, _) => expr.position(),
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#[cfg(not(feature = "no_float"))]
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Expr::FloatConstant(_, pos) => *pos,
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#[cfg(not(feature = "no_index"))]
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Expr::Array(_, pos) => *pos,
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#[cfg(not(feature = "no_index"))]
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Expr::Index(expr, _, _) => expr.position(),
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}
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}
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/// Is the expression pure?
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///
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/// A pure expression has no side effects.
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pub fn is_pure(&self) -> bool {
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match self {
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#[cfg(not(feature = "no_index"))]
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Expr::Array(expressions, _) => expressions.iter().all(Expr::is_pure),
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#[cfg(not(feature = "no_index"))]
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Expr::Index(x, y, _) => x.is_pure() && y.is_pure(),
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Expr::And(x, y) | Expr::Or(x, y) => x.is_pure() && y.is_pure(),
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Expr::Stmt(stmt, _) => stmt.is_pure(),
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expr => expr.is_constant() || matches!(expr, Expr::Variable(_, _)),
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}
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}
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/// Is the expression a constant?
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pub fn is_constant(&self) -> bool {
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match self {
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Expr::IntegerConstant(_, _)
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| Expr::CharConstant(_, _)
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| Expr::StringConstant(_, _)
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| Expr::True(_)
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| Expr::False(_)
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| Expr::Unit(_) => true,
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#[cfg(not(feature = "no_float"))]
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Expr::FloatConstant(_, _) => true,
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|
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// An array literal is constant if all items are constant
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#[cfg(not(feature = "no_index"))]
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Expr::Array(expressions, _) => expressions.iter().all(Expr::is_constant),
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_ => false,
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}
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}
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}
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/// Tokens.
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#[derive(Debug, PartialEq, Clone)]
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pub enum Token {
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IntegerConstant(INT),
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#[cfg(not(feature = "no_float"))]
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FloatConstant(FLOAT),
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Identifier(String),
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CharConstant(char),
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StringConst(String),
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LeftBrace,
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RightBrace,
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LeftParen,
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RightParen,
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#[cfg(not(feature = "no_index"))]
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LeftBracket,
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#[cfg(not(feature = "no_index"))]
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RightBracket,
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Plus,
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UnaryPlus,
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Minus,
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UnaryMinus,
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Multiply,
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Divide,
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Modulo,
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PowerOf,
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LeftShift,
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RightShift,
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SemiColon,
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Colon,
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Comma,
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Period,
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Equals,
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True,
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False,
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Let,
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Const,
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If,
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Else,
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While,
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Loop,
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For,
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In,
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LessThan,
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GreaterThan,
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LessThanEqualsTo,
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GreaterThanEqualsTo,
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EqualsTo,
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NotEqualsTo,
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Bang,
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Pipe,
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Or,
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XOr,
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Ampersand,
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And,
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#[cfg(not(feature = "no_function"))]
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Fn,
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Break,
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Return,
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Throw,
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PlusAssign,
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MinusAssign,
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MultiplyAssign,
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DivideAssign,
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LeftShiftAssign,
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RightShiftAssign,
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AndAssign,
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OrAssign,
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XOrAssign,
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ModuloAssign,
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PowerOfAssign,
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LexError(LexError),
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}
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|
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impl Token {
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/// Get the syntax of the token.
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pub fn syntax<'a>(&'a self) -> Cow<'a, str> {
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use self::Token::*;
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|
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match self {
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IntegerConstant(i) => i.to_string().into(),
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#[cfg(not(feature = "no_float"))]
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FloatConstant(f) => f.to_string().into(),
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Identifier(s) => s.into(),
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CharConstant(c) => c.to_string().into(),
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LexError(err) => err.to_string().into(),
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|
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token => (match token {
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StringConst(_) => "string",
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LeftBrace => "{",
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RightBrace => "}",
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LeftParen => "(",
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RightParen => ")",
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#[cfg(not(feature = "no_index"))]
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LeftBracket => "[",
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#[cfg(not(feature = "no_index"))]
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RightBracket => "]",
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Plus => "+",
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UnaryPlus => "+",
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Minus => "-",
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UnaryMinus => "-",
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Multiply => "*",
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Divide => "/",
|
|
SemiColon => ";",
|
|
Colon => ":",
|
|
Comma => ",",
|
|
Period => ".",
|
|
Equals => "=",
|
|
True => "true",
|
|
False => "false",
|
|
Let => "let",
|
|
Const => "const",
|
|
If => "if",
|
|
Else => "else",
|
|
While => "while",
|
|
Loop => "loop",
|
|
LessThan => "<",
|
|
GreaterThan => ">",
|
|
Bang => "!",
|
|
LessThanEqualsTo => "<=",
|
|
GreaterThanEqualsTo => ">=",
|
|
EqualsTo => "==",
|
|
NotEqualsTo => "!=",
|
|
Pipe => "|",
|
|
Or => "||",
|
|
Ampersand => "&",
|
|
And => "&&",
|
|
#[cfg(not(feature = "no_function"))]
|
|
Fn => "fn",
|
|
Break => "break",
|
|
Return => "return",
|
|
Throw => "throw",
|
|
PlusAssign => "+=",
|
|
MinusAssign => "-=",
|
|
MultiplyAssign => "*=",
|
|
DivideAssign => "/=",
|
|
LeftShiftAssign => "<<=",
|
|
RightShiftAssign => ">>=",
|
|
AndAssign => "&=",
|
|
OrAssign => "|=",
|
|
XOrAssign => "^=",
|
|
LeftShift => "<<",
|
|
RightShift => ">>",
|
|
XOr => "^",
|
|
Modulo => "%",
|
|
ModuloAssign => "%=",
|
|
PowerOf => "~",
|
|
PowerOfAssign => "~=",
|
|
For => "for",
|
|
In => "in",
|
|
_ => panic!("operator should be match in outer scope"),
|
|
})
|
|
.into(),
|
|
}
|
|
}
|
|
|
|
// If another operator is after these, it's probably an unary operator
|
|
// (not sure about fn name).
|
|
pub fn is_next_unary(&self) -> bool {
|
|
use self::Token::*;
|
|
|
|
match self {
|
|
LexError(_) |
|
|
LeftBrace | // (+expr) - is unary
|
|
// RightBrace | {expr} - expr not unary & is closing
|
|
LeftParen | // {-expr} - is unary
|
|
// RightParen | (expr) - expr not unary & is closing
|
|
Plus |
|
|
UnaryPlus |
|
|
Minus |
|
|
UnaryMinus |
|
|
Multiply |
|
|
Divide |
|
|
Colon |
|
|
Comma |
|
|
Period |
|
|
Equals |
|
|
LessThan |
|
|
GreaterThan |
|
|
Bang |
|
|
LessThanEqualsTo |
|
|
GreaterThanEqualsTo |
|
|
EqualsTo |
|
|
NotEqualsTo |
|
|
Pipe |
|
|
Or |
|
|
Ampersand |
|
|
And |
|
|
If |
|
|
While |
|
|
PlusAssign |
|
|
MinusAssign |
|
|
MultiplyAssign |
|
|
DivideAssign |
|
|
LeftShiftAssign |
|
|
RightShiftAssign |
|
|
AndAssign |
|
|
OrAssign |
|
|
XOrAssign |
|
|
LeftShift |
|
|
RightShift |
|
|
XOr |
|
|
Modulo |
|
|
ModuloAssign |
|
|
Return |
|
|
Throw |
|
|
PowerOf |
|
|
In |
|
|
PowerOfAssign => true,
|
|
|
|
#[cfg(not(feature = "no_index"))]
|
|
LeftBracket => true, // [-expr] - is unary
|
|
// RightBracket | [expr] - expr not unary & is closing
|
|
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
/// Get the precedence number of the token.
|
|
pub fn precedence(&self) -> u8 {
|
|
match self {
|
|
Self::Equals
|
|
| Self::PlusAssign
|
|
| Self::MinusAssign
|
|
| Self::MultiplyAssign
|
|
| Self::DivideAssign
|
|
| Self::LeftShiftAssign
|
|
| Self::RightShiftAssign
|
|
| Self::AndAssign
|
|
| Self::OrAssign
|
|
| Self::XOrAssign
|
|
| Self::ModuloAssign
|
|
| Self::PowerOfAssign => 10,
|
|
|
|
Self::Or | Self::XOr | Self::Pipe => 50,
|
|
|
|
Self::And | Self::Ampersand => 60,
|
|
|
|
Self::LessThan
|
|
| Self::LessThanEqualsTo
|
|
| Self::GreaterThan
|
|
| Self::GreaterThanEqualsTo
|
|
| Self::EqualsTo
|
|
| Self::NotEqualsTo => 70,
|
|
|
|
Self::Plus | Self::Minus => 80,
|
|
|
|
Self::Divide | Self::Multiply | Self::PowerOf => 90,
|
|
|
|
Self::LeftShift | Self::RightShift => 100,
|
|
|
|
Self::Modulo => 110,
|
|
|
|
Self::Period => 120,
|
|
|
|
_ => 0,
|
|
}
|
|
}
|
|
|
|
/// Does an expression bind to the right (instead of left)?
|
|
pub fn is_bind_right(&self) -> bool {
|
|
match self {
|
|
// Assignments bind to the right
|
|
Self::Equals
|
|
| Self::PlusAssign
|
|
| Self::MinusAssign
|
|
| Self::MultiplyAssign
|
|
| Self::DivideAssign
|
|
| Self::LeftShiftAssign
|
|
| Self::RightShiftAssign
|
|
| Self::AndAssign
|
|
| Self::OrAssign
|
|
| Self::XOrAssign
|
|
| Self::ModuloAssign
|
|
| Self::PowerOfAssign => true,
|
|
|
|
// Property access binds to the right
|
|
Self::Period => true,
|
|
|
|
_ => false,
|
|
}
|
|
}
|
|
}
|
|
|
|
/// An iterator on a `Token` stream.
|
|
pub struct TokenIterator<'a> {
|
|
/// The last token seen.
|
|
last: Token,
|
|
/// Current position.
|
|
pos: Position,
|
|
/// The input characters stream.
|
|
char_stream: Peekable<Chars<'a>>,
|
|
}
|
|
|
|
impl<'a> TokenIterator<'a> {
|
|
/// Move the current position one character ahead.
|
|
fn advance(&mut self) {
|
|
self.pos.advance();
|
|
}
|
|
/// Move the current position back one character.
|
|
///
|
|
/// # Panics
|
|
///
|
|
/// Panics if already at the beginning of a line - cannot rewind to the previous line.
|
|
fn rewind(&mut self) {
|
|
self.pos.rewind();
|
|
}
|
|
/// Move the current position to the next line.
|
|
fn new_line(&mut self) {
|
|
self.pos.new_line()
|
|
}
|
|
|
|
/// Parse a string literal wrapped by `enclosing_char`.
|
|
pub fn parse_string_literal(
|
|
&mut self,
|
|
enclosing_char: char,
|
|
) -> Result<String, (LexError, Position)> {
|
|
let mut result = Vec::new();
|
|
let mut escape = String::with_capacity(12);
|
|
|
|
loop {
|
|
let next_char = self.char_stream.next();
|
|
self.advance();
|
|
|
|
match next_char.ok_or((LERR::UnterminatedString, Position::eof()))? {
|
|
// \...
|
|
'\\' if escape.is_empty() => {
|
|
escape.push('\\');
|
|
}
|
|
// \\
|
|
'\\' if !escape.is_empty() => {
|
|
escape.clear();
|
|
result.push('\\');
|
|
}
|
|
// \t
|
|
't' if !escape.is_empty() => {
|
|
escape.clear();
|
|
result.push('\t');
|
|
}
|
|
// \n
|
|
'n' if !escape.is_empty() => {
|
|
escape.clear();
|
|
result.push('\n');
|
|
}
|
|
// \r
|
|
'r' if !escape.is_empty() => {
|
|
escape.clear();
|
|
result.push('\r');
|
|
}
|
|
// \x??, \u????, \U????????
|
|
ch @ 'x' | ch @ 'u' | ch @ 'U' if !escape.is_empty() => {
|
|
let mut seq = escape.clone();
|
|
seq.push(ch);
|
|
escape.clear();
|
|
|
|
let mut out_val: u32 = 0;
|
|
let len = match ch {
|
|
'x' => 2,
|
|
'u' => 4,
|
|
'U' => 8,
|
|
_ => panic!("should be 'x', 'u' or 'U'"),
|
|
};
|
|
|
|
for _ in 0..len {
|
|
let c = self.char_stream.next().ok_or_else(|| {
|
|
(LERR::MalformedEscapeSequence(seq.to_string()), self.pos)
|
|
})?;
|
|
|
|
seq.push(c);
|
|
self.advance();
|
|
|
|
out_val *= 16;
|
|
out_val += c.to_digit(16).ok_or_else(|| {
|
|
(LERR::MalformedEscapeSequence(seq.to_string()), self.pos)
|
|
})?;
|
|
}
|
|
|
|
result.push(
|
|
char::from_u32(out_val)
|
|
.ok_or_else(|| (LERR::MalformedEscapeSequence(seq), self.pos))?,
|
|
);
|
|
}
|
|
|
|
// \{enclosing_char} - escaped
|
|
ch if enclosing_char == ch && !escape.is_empty() => result.push(ch),
|
|
|
|
// Close wrapper
|
|
ch if enclosing_char == ch && escape.is_empty() => break,
|
|
|
|
// Unknown escape sequence
|
|
_ if !escape.is_empty() => {
|
|
return Err((LERR::MalformedEscapeSequence(escape), self.pos))
|
|
}
|
|
|
|
// Cannot have new-lines inside string literals
|
|
'\n' => {
|
|
self.rewind();
|
|
return Err((LERR::UnterminatedString, self.pos));
|
|
}
|
|
|
|
// All other characters
|
|
ch => {
|
|
escape.clear();
|
|
result.push(ch);
|
|
}
|
|
}
|
|
}
|
|
|
|
Ok(result.iter().collect())
|
|
}
|
|
|
|
/// Get the next token.
|
|
fn inner_next(&mut self) -> Option<(Token, Position)> {
|
|
let mut negated = false;
|
|
|
|
while let Some(c) = self.char_stream.next() {
|
|
self.advance();
|
|
|
|
let pos = self.pos;
|
|
|
|
match c {
|
|
// \n
|
|
'\n' => self.new_line(),
|
|
// digit ...
|
|
'0'..='9' => {
|
|
let mut result = Vec::new();
|
|
let mut radix_base: Option<u32> = None;
|
|
result.push(c);
|
|
|
|
while let Some(&next_char) = self.char_stream.peek() {
|
|
match next_char {
|
|
'0'..='9' | '_' => {
|
|
result.push(next_char);
|
|
self.char_stream.next();
|
|
self.advance();
|
|
}
|
|
#[cfg(not(feature = "no_float"))]
|
|
'.' => {
|
|
result.push(next_char);
|
|
self.char_stream.next();
|
|
self.advance();
|
|
while let Some(&next_char_in_float) = self.char_stream.peek() {
|
|
match next_char_in_float {
|
|
'0'..='9' | '_' => {
|
|
result.push(next_char_in_float);
|
|
self.char_stream.next();
|
|
self.advance();
|
|
}
|
|
_ => break,
|
|
}
|
|
}
|
|
}
|
|
// 0x????, 0o????, 0b????
|
|
ch @ 'x' | ch @ 'X' | ch @ 'o' | ch @ 'O' | ch @ 'b' | ch @ 'B'
|
|
if c == '0' =>
|
|
{
|
|
result.push(next_char);
|
|
self.char_stream.next();
|
|
self.advance();
|
|
|
|
let valid = match ch {
|
|
'x' | 'X' => [
|
|
'a', 'b', 'c', 'd', 'e', 'f', 'A', 'B', 'C', 'D', 'E', 'F',
|
|
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '_',
|
|
],
|
|
'o' | 'O' => [
|
|
'0', '1', '2', '3', '4', '5', '6', '7', '_', '_', '_', '_',
|
|
'_', '_', '_', '_', '_', '_', '_', '_', '_', '_', '_',
|
|
],
|
|
'b' | 'B' => [
|
|
'0', '1', '_', '_', '_', '_', '_', '_', '_', '_', '_', '_',
|
|
'_', '_', '_', '_', '_', '_', '_', '_', '_', '_', '_',
|
|
],
|
|
_ => panic!("unexpected character {}", ch),
|
|
};
|
|
|
|
radix_base = Some(match ch {
|
|
'x' | 'X' => 16,
|
|
'o' | 'O' => 8,
|
|
'b' | 'B' => 2,
|
|
_ => panic!("unexpected character {}", ch),
|
|
});
|
|
|
|
while let Some(&next_char_in_hex) = self.char_stream.peek() {
|
|
if !valid.contains(&next_char_in_hex) {
|
|
break;
|
|
}
|
|
|
|
result.push(next_char_in_hex);
|
|
self.char_stream.next();
|
|
self.advance();
|
|
}
|
|
}
|
|
|
|
_ => break,
|
|
}
|
|
}
|
|
|
|
if negated {
|
|
result.insert(0, '-');
|
|
}
|
|
|
|
// Parse number
|
|
if let Some(radix) = radix_base {
|
|
let out: String = result.iter().skip(2).filter(|&&c| c != '_').collect();
|
|
|
|
return Some((
|
|
INT::from_str_radix(&out, radix)
|
|
.map(Token::IntegerConstant)
|
|
.unwrap_or_else(|_| {
|
|
Token::LexError(LERR::MalformedNumber(result.iter().collect()))
|
|
}),
|
|
pos,
|
|
));
|
|
} else {
|
|
let out: String = result.iter().filter(|&&c| c != '_').collect();
|
|
let num = INT::from_str(&out).map(Token::IntegerConstant);
|
|
|
|
// If integer parsing is unnecessary, try float instead
|
|
#[cfg(not(feature = "no_float"))]
|
|
let num = num.or_else(|_| FLOAT::from_str(&out).map(Token::FloatConstant));
|
|
|
|
return Some((
|
|
num.unwrap_or_else(|_| {
|
|
Token::LexError(LERR::MalformedNumber(result.iter().collect()))
|
|
}),
|
|
pos,
|
|
));
|
|
}
|
|
}
|
|
// letter ...
|
|
'A'..='Z' | 'a'..='z' | '_' => {
|
|
let mut result = Vec::new();
|
|
result.push(c);
|
|
|
|
while let Some(&next_char) = self.char_stream.peek() {
|
|
match next_char {
|
|
x if x.is_ascii_alphanumeric() || x == '_' => {
|
|
result.push(x);
|
|
self.char_stream.next();
|
|
self.advance();
|
|
}
|
|
_ => break,
|
|
}
|
|
}
|
|
|
|
let is_valid_identifier = result
|
|
.iter()
|
|
.find(|&ch| char::is_ascii_alphanumeric(ch)) // first alpha-numeric character
|
|
.map(char::is_ascii_alphabetic) // is a letter
|
|
.unwrap_or(false); // if no alpha-numeric at all - syntax error
|
|
|
|
let identifier: String = result.iter().collect();
|
|
|
|
if !is_valid_identifier {
|
|
return Some((Token::LexError(LERR::MalformedIdentifier(identifier)), pos));
|
|
}
|
|
|
|
return Some((
|
|
match identifier.as_str() {
|
|
"true" => Token::True,
|
|
"false" => Token::False,
|
|
"let" => Token::Let,
|
|
"const" => Token::Const,
|
|
"if" => Token::If,
|
|
"else" => Token::Else,
|
|
"while" => Token::While,
|
|
"loop" => Token::Loop,
|
|
"break" => Token::Break,
|
|
"return" => Token::Return,
|
|
"throw" => Token::Throw,
|
|
"for" => Token::For,
|
|
"in" => Token::In,
|
|
|
|
#[cfg(not(feature = "no_function"))]
|
|
"fn" => Token::Fn,
|
|
|
|
_ => Token::Identifier(identifier),
|
|
},
|
|
pos,
|
|
));
|
|
}
|
|
// " - string literal
|
|
'"' => {
|
|
return match self.parse_string_literal('"') {
|
|
Ok(out) => Some((Token::StringConst(out), pos)),
|
|
Err(e) => Some((Token::LexError(e.0), e.1)),
|
|
}
|
|
}
|
|
// ' - character literal
|
|
'\'' => match self.parse_string_literal('\'') {
|
|
Ok(result) => {
|
|
let mut chars = result.chars();
|
|
|
|
return Some((
|
|
if let Some(first_char) = chars.next() {
|
|
if chars.count() != 0 {
|
|
Token::LexError(LERR::MalformedChar(format!("'{}'", result)))
|
|
} else {
|
|
Token::CharConstant(first_char)
|
|
}
|
|
} else {
|
|
Token::LexError(LERR::MalformedChar(format!("'{}'", result)))
|
|
},
|
|
pos,
|
|
));
|
|
}
|
|
Err(e) => return Some((Token::LexError(e.0), e.1)),
|
|
},
|
|
|
|
// Braces
|
|
'{' => return Some((Token::LeftBrace, pos)),
|
|
'}' => return Some((Token::RightBrace, pos)),
|
|
|
|
// Parentheses
|
|
'(' => return Some((Token::LeftParen, pos)),
|
|
')' => return Some((Token::RightParen, pos)),
|
|
|
|
// Indexing
|
|
#[cfg(not(feature = "no_index"))]
|
|
'[' => return Some((Token::LeftBracket, pos)),
|
|
#[cfg(not(feature = "no_index"))]
|
|
']' => return Some((Token::RightBracket, pos)),
|
|
|
|
// Operators
|
|
'+' => {
|
|
return Some((
|
|
match self.char_stream.peek() {
|
|
Some(&'=') => {
|
|
self.char_stream.next();
|
|
self.advance();
|
|
Token::PlusAssign
|
|
}
|
|
_ if self.last.is_next_unary() => Token::UnaryPlus,
|
|
_ => Token::Plus,
|
|
},
|
|
pos,
|
|
))
|
|
}
|
|
'-' => match self.char_stream.peek() {
|
|
// Negative number?
|
|
Some('0'..='9') if self.last.is_next_unary() => negated = true,
|
|
Some('0'..='9') => return Some((Token::Minus, pos)),
|
|
Some('=') => {
|
|
self.char_stream.next();
|
|
self.advance();
|
|
return Some((Token::MinusAssign, pos));
|
|
}
|
|
_ if self.last.is_next_unary() => return Some((Token::UnaryMinus, pos)),
|
|
_ => return Some((Token::Minus, pos)),
|
|
},
|
|
'*' => {
|
|
return Some((
|
|
match self.char_stream.peek() {
|
|
Some(&'=') => {
|
|
self.char_stream.next();
|
|
self.advance();
|
|
Token::MultiplyAssign
|
|
}
|
|
_ => Token::Multiply,
|
|
},
|
|
pos,
|
|
))
|
|
}
|
|
'/' => match self.char_stream.peek() {
|
|
Some(&'/') => {
|
|
self.char_stream.next();
|
|
self.advance();
|
|
while let Some(c) = self.char_stream.next() {
|
|
match c {
|
|
'\n' => {
|
|
self.new_line();
|
|
break;
|
|
}
|
|
_ => self.advance(),
|
|
}
|
|
}
|
|
}
|
|
Some(&'*') => {
|
|
let mut level = 1;
|
|
self.char_stream.next();
|
|
self.advance();
|
|
while let Some(c) = self.char_stream.next() {
|
|
self.advance();
|
|
|
|
match c {
|
|
'/' => {
|
|
if let Some('*') = self.char_stream.next() {
|
|
level += 1;
|
|
}
|
|
self.advance();
|
|
}
|
|
'*' => {
|
|
if let Some('/') = self.char_stream.next() {
|
|
level -= 1;
|
|
}
|
|
self.advance();
|
|
}
|
|
'\n' => self.new_line(),
|
|
_ => (),
|
|
}
|
|
|
|
if level == 0 {
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
Some(&'=') => {
|
|
self.char_stream.next();
|
|
self.advance();
|
|
return Some((Token::DivideAssign, pos));
|
|
}
|
|
_ => return Some((Token::Divide, pos)),
|
|
},
|
|
';' => return Some((Token::SemiColon, pos)),
|
|
':' => return Some((Token::Colon, pos)),
|
|
',' => return Some((Token::Comma, pos)),
|
|
'.' => return Some((Token::Period, pos)),
|
|
'=' => match self.char_stream.peek() {
|
|
Some(&'=') => {
|
|
self.char_stream.next();
|
|
self.advance();
|
|
return Some((Token::EqualsTo, pos));
|
|
}
|
|
_ => return Some((Token::Equals, pos)),
|
|
},
|
|
'<' => match self.char_stream.peek() {
|
|
Some(&'=') => {
|
|
self.char_stream.next();
|
|
self.advance();
|
|
return Some((Token::LessThanEqualsTo, pos));
|
|
}
|
|
Some(&'<') => {
|
|
self.char_stream.next();
|
|
self.advance();
|
|
return match self.char_stream.peek() {
|
|
Some(&'=') => {
|
|
self.char_stream.next();
|
|
self.advance();
|
|
Some((Token::LeftShiftAssign, pos))
|
|
}
|
|
_ => {
|
|
self.char_stream.next();
|
|
self.advance();
|
|
Some((Token::LeftShift, pos))
|
|
}
|
|
};
|
|
}
|
|
_ => return Some((Token::LessThan, pos)),
|
|
},
|
|
'>' => {
|
|
return Some((
|
|
match self.char_stream.peek() {
|
|
Some(&'=') => {
|
|
self.char_stream.next();
|
|
self.advance();
|
|
Token::GreaterThanEqualsTo
|
|
}
|
|
Some(&'>') => {
|
|
self.char_stream.next();
|
|
self.advance();
|
|
match self.char_stream.peek() {
|
|
Some(&'=') => {
|
|
self.char_stream.next();
|
|
self.advance();
|
|
Token::RightShiftAssign
|
|
}
|
|
_ => {
|
|
self.char_stream.next();
|
|
self.advance();
|
|
Token::RightShift
|
|
}
|
|
}
|
|
}
|
|
_ => Token::GreaterThan,
|
|
},
|
|
pos,
|
|
))
|
|
}
|
|
'!' => {
|
|
return Some((
|
|
match self.char_stream.peek() {
|
|
Some(&'=') => {
|
|
self.char_stream.next();
|
|
self.advance();
|
|
Token::NotEqualsTo
|
|
}
|
|
_ => Token::Bang,
|
|
},
|
|
pos,
|
|
))
|
|
}
|
|
'|' => {
|
|
return Some((
|
|
match self.char_stream.peek() {
|
|
Some(&'|') => {
|
|
self.char_stream.next();
|
|
self.advance();
|
|
Token::Or
|
|
}
|
|
Some(&'=') => {
|
|
self.char_stream.next();
|
|
self.advance();
|
|
Token::OrAssign
|
|
}
|
|
_ => Token::Pipe,
|
|
},
|
|
pos,
|
|
))
|
|
}
|
|
'&' => {
|
|
return Some((
|
|
match self.char_stream.peek() {
|
|
Some(&'&') => {
|
|
self.char_stream.next();
|
|
self.advance();
|
|
Token::And
|
|
}
|
|
Some(&'=') => {
|
|
self.char_stream.next();
|
|
self.advance();
|
|
Token::AndAssign
|
|
}
|
|
_ => Token::Ampersand,
|
|
},
|
|
pos,
|
|
))
|
|
}
|
|
'^' => {
|
|
return Some((
|
|
match self.char_stream.peek() {
|
|
Some(&'=') => {
|
|
self.char_stream.next();
|
|
self.advance();
|
|
Token::XOrAssign
|
|
}
|
|
_ => Token::XOr,
|
|
},
|
|
pos,
|
|
))
|
|
}
|
|
'%' => {
|
|
return Some((
|
|
match self.char_stream.peek() {
|
|
Some(&'=') => {
|
|
self.char_stream.next();
|
|
self.advance();
|
|
Token::ModuloAssign
|
|
}
|
|
_ => Token::Modulo,
|
|
},
|
|
pos,
|
|
))
|
|
}
|
|
'~' => {
|
|
return Some((
|
|
match self.char_stream.peek() {
|
|
Some(&'=') => {
|
|
self.char_stream.next();
|
|
self.advance();
|
|
Token::PowerOfAssign
|
|
}
|
|
_ => Token::PowerOf,
|
|
},
|
|
pos,
|
|
))
|
|
}
|
|
x if x.is_whitespace() => (),
|
|
x => return Some((Token::LexError(LERR::UnexpectedChar(x)), pos)),
|
|
}
|
|
}
|
|
|
|
None
|
|
}
|
|
}
|
|
|
|
impl<'a> Iterator for TokenIterator<'a> {
|
|
type Item = (Token, Position);
|
|
|
|
// TODO - perhaps this could be optimized?
|
|
fn next(&mut self) -> Option<Self::Item> {
|
|
self.inner_next().map(|x| {
|
|
self.last = x.0.clone();
|
|
x
|
|
})
|
|
}
|
|
}
|
|
|
|
/// Tokenize an input text stream.
|
|
pub fn lex(input: &str) -> TokenIterator<'_> {
|
|
TokenIterator {
|
|
last: Token::LexError(LERR::InputError("".into())),
|
|
pos: Position::new(1, 0),
|
|
char_stream: input.chars().peekable(),
|
|
}
|
|
}
|
|
|
|
/// Parse ( expr )
|
|
fn parse_paren_expr<'a>(
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
begin: Position,
|
|
allow_stmt_expr: bool,
|
|
) -> Result<Expr, ParseError> {
|
|
match input.peek() {
|
|
// ()
|
|
Some((Token::RightParen, _)) => {
|
|
input.next();
|
|
return Ok(Expr::Unit(begin));
|
|
}
|
|
_ => (),
|
|
}
|
|
|
|
let expr = parse_expr(input, allow_stmt_expr)?;
|
|
|
|
match input.next() {
|
|
// ( xxx )
|
|
Some((Token::RightParen, _)) => Ok(expr),
|
|
// ( xxx ???
|
|
Some((_, pos)) => {
|
|
return Err(ParseError::new(
|
|
PERR::MissingRightParen("a matching ( in the expression".into()),
|
|
pos,
|
|
))
|
|
}
|
|
// ( xxx
|
|
None => Err(ParseError::new(
|
|
PERR::MissingRightParen("a matching ( in the expression".into()),
|
|
Position::eof(),
|
|
)),
|
|
}
|
|
}
|
|
|
|
/// Parse a function call.
|
|
fn parse_call_expr<'a>(
|
|
id: String,
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
begin: Position,
|
|
allow_stmt_expr: bool,
|
|
) -> Result<Expr, ParseError> {
|
|
let mut args_expr_list = Vec::new();
|
|
|
|
// id()
|
|
if let (Token::RightParen, _) = input.peek().ok_or_else(|| {
|
|
ParseError::new(
|
|
PERR::MissingRightParen(format!(
|
|
"closing the arguments to call of function '{}'",
|
|
id
|
|
)),
|
|
Position::eof(),
|
|
)
|
|
})? {
|
|
input.next();
|
|
return Ok(Expr::FunctionCall(id, args_expr_list, None, begin));
|
|
}
|
|
|
|
loop {
|
|
args_expr_list.push(parse_expr(input, allow_stmt_expr)?);
|
|
|
|
match input.peek().ok_or_else(|| {
|
|
ParseError::new(
|
|
PERR::MissingRightParen(format!(
|
|
"closing the arguments to call of function '{}'",
|
|
id
|
|
)),
|
|
Position::eof(),
|
|
)
|
|
})? {
|
|
(Token::RightParen, _) => {
|
|
input.next();
|
|
return Ok(Expr::FunctionCall(id, args_expr_list, None, begin));
|
|
}
|
|
(Token::Comma, _) => (),
|
|
(_, pos) => {
|
|
return Err(ParseError::new(
|
|
PERR::MissingComma(format!(
|
|
"separating the arguments to call of function '{}'",
|
|
id
|
|
)),
|
|
*pos,
|
|
))
|
|
}
|
|
}
|
|
|
|
input.next();
|
|
}
|
|
}
|
|
|
|
/// Parse an indexing expression.s
|
|
#[cfg(not(feature = "no_index"))]
|
|
fn parse_index_expr<'a>(
|
|
lhs: Box<Expr>,
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
pos: Position,
|
|
allow_stmt_expr: bool,
|
|
) -> Result<Expr, ParseError> {
|
|
let idx_expr = parse_expr(input, allow_stmt_expr)?;
|
|
|
|
// Check type of indexing - must be integer
|
|
match &idx_expr {
|
|
// lhs[int]
|
|
Expr::IntegerConstant(i, pos) if *i < 0 => {
|
|
return Err(ParseError::new(
|
|
PERR::MalformedIndexExpr(format!(
|
|
"Array access expects non-negative index: {} < 0",
|
|
i
|
|
)),
|
|
*pos,
|
|
))
|
|
}
|
|
// lhs[float]
|
|
#[cfg(not(feature = "no_float"))]
|
|
Expr::FloatConstant(_, pos) => {
|
|
return Err(ParseError::new(
|
|
PERR::MalformedIndexExpr("Array access expects integer index, not a float".into()),
|
|
*pos,
|
|
))
|
|
}
|
|
// lhs[char]
|
|
Expr::CharConstant(_, pos) => {
|
|
return Err(ParseError::new(
|
|
PERR::MalformedIndexExpr(
|
|
"Array access expects integer index, not a character".into(),
|
|
),
|
|
*pos,
|
|
))
|
|
}
|
|
// lhs[string]
|
|
Expr::StringConstant(_, pos) => {
|
|
return Err(ParseError::new(
|
|
PERR::MalformedIndexExpr("Array access expects integer index, not a string".into()),
|
|
*pos,
|
|
))
|
|
}
|
|
// lhs[??? = ??? ], lhs[()]
|
|
Expr::Assignment(_, _, pos) | Expr::Unit(pos) => {
|
|
return Err(ParseError::new(
|
|
PERR::MalformedIndexExpr("Array access expects integer index, not ()".into()),
|
|
*pos,
|
|
))
|
|
}
|
|
// lhs[??? && ???], lhs[??? || ???]
|
|
Expr::And(lhs, _) | Expr::Or(lhs, _) => {
|
|
return Err(ParseError::new(
|
|
PERR::MalformedIndexExpr(
|
|
"Array access expects integer index, not a boolean".into(),
|
|
),
|
|
lhs.position(),
|
|
))
|
|
}
|
|
// lhs[true], lhs[false]
|
|
Expr::True(pos) | Expr::False(pos) => {
|
|
return Err(ParseError::new(
|
|
PERR::MalformedIndexExpr(
|
|
"Array access expects integer index, not a boolean".into(),
|
|
),
|
|
*pos,
|
|
))
|
|
}
|
|
// All other expressions
|
|
_ => (),
|
|
}
|
|
|
|
// Check if there is a closing bracket
|
|
match input.peek().ok_or_else(|| {
|
|
ParseError::new(
|
|
PERR::MissingRightBracket("index expression".into()),
|
|
Position::eof(),
|
|
)
|
|
})? {
|
|
(Token::RightBracket, _) => {
|
|
input.next();
|
|
return Ok(Expr::Index(lhs, Box::new(idx_expr), pos));
|
|
}
|
|
(_, pos) => {
|
|
return Err(ParseError::new(
|
|
PERR::MissingRightBracket("index expression".into()),
|
|
*pos,
|
|
))
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Parse an expression that begins with an identifier.
|
|
fn parse_ident_expr<'a>(
|
|
id: String,
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
begin: Position,
|
|
allow_stmt_expr: bool,
|
|
) -> Result<Expr, ParseError> {
|
|
match input.peek() {
|
|
// id(...) - function call
|
|
Some((Token::LeftParen, _)) => {
|
|
input.next();
|
|
parse_call_expr(id, input, begin, allow_stmt_expr)
|
|
}
|
|
// id[...] - indexing
|
|
#[cfg(not(feature = "no_index"))]
|
|
Some((Token::LeftBracket, pos)) => {
|
|
let pos = *pos;
|
|
input.next();
|
|
parse_index_expr(
|
|
Box::new(Expr::Variable(id, begin)),
|
|
input,
|
|
pos,
|
|
allow_stmt_expr,
|
|
)
|
|
}
|
|
// id - variable
|
|
Some(_) => Ok(Expr::Variable(id, begin)),
|
|
// EOF
|
|
None => Ok(Expr::Variable(id, begin)),
|
|
}
|
|
}
|
|
|
|
/// Parse an array literal.
|
|
#[cfg(not(feature = "no_index"))]
|
|
fn parse_array_literal<'a>(
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
begin: Position,
|
|
allow_stmt_expr: bool,
|
|
) -> Result<Expr, ParseError> {
|
|
let mut arr = Vec::new();
|
|
|
|
if !matches!(input.peek(), Some((Token::RightBracket, _))) {
|
|
while input.peek().is_some() {
|
|
arr.push(parse_expr(input, allow_stmt_expr)?);
|
|
|
|
match input.peek().ok_or_else(|| {
|
|
ParseError(
|
|
PERR::MissingRightBracket("separating items in array literal".into()),
|
|
Position::eof(),
|
|
)
|
|
})? {
|
|
(Token::Comma, _) => {
|
|
input.next();
|
|
}
|
|
(Token::RightBracket, _) => break,
|
|
(_, pos) => {
|
|
return Err(ParseError(
|
|
PERR::MissingComma("separating items in array literal".into()),
|
|
*pos,
|
|
))
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
match input.peek().ok_or_else(|| {
|
|
ParseError::new(
|
|
PERR::MissingRightBracket("the end of array literal".into()),
|
|
Position::eof(),
|
|
)
|
|
})? {
|
|
(Token::RightBracket, _) => {
|
|
input.next();
|
|
Ok(Expr::Array(arr, begin))
|
|
}
|
|
(_, pos) => Err(ParseError::new(
|
|
PERR::MissingRightBracket("the end of array literal".into()),
|
|
*pos,
|
|
)),
|
|
}
|
|
}
|
|
|
|
/// Parse a primary expression.
|
|
fn parse_primary<'a>(
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
allow_stmt_expr: bool,
|
|
) -> Result<Expr, ParseError> {
|
|
let token = match input
|
|
.peek()
|
|
.ok_or_else(|| ParseError::new(PERR::UnexpectedEOF, Position::eof()))?
|
|
{
|
|
// { - block statement as expression
|
|
(Token::LeftBrace, pos) if allow_stmt_expr => {
|
|
let pos = *pos;
|
|
return parse_block(input, false, allow_stmt_expr)
|
|
.map(|block| Expr::Stmt(Box::new(block), pos));
|
|
}
|
|
_ => input.next().expect("should be a token"),
|
|
};
|
|
|
|
let mut can_be_indexed = false;
|
|
|
|
let mut root_expr = match token {
|
|
#[cfg(not(feature = "no_float"))]
|
|
(Token::FloatConstant(x), pos) => Ok(Expr::FloatConstant(x, pos)),
|
|
|
|
(Token::IntegerConstant(x), pos) => Ok(Expr::IntegerConstant(x, pos)),
|
|
(Token::CharConstant(c), pos) => Ok(Expr::CharConstant(c, pos)),
|
|
(Token::StringConst(s), pos) => {
|
|
can_be_indexed = true;
|
|
Ok(Expr::StringConstant(s, pos))
|
|
}
|
|
(Token::Identifier(s), pos) => {
|
|
can_be_indexed = true;
|
|
parse_ident_expr(s, input, pos, allow_stmt_expr)
|
|
}
|
|
(Token::LeftParen, pos) => {
|
|
can_be_indexed = true;
|
|
parse_paren_expr(input, pos, allow_stmt_expr)
|
|
}
|
|
#[cfg(not(feature = "no_index"))]
|
|
(Token::LeftBracket, pos) => {
|
|
can_be_indexed = true;
|
|
parse_array_literal(input, pos, allow_stmt_expr)
|
|
}
|
|
(Token::True, pos) => Ok(Expr::True(pos)),
|
|
(Token::False, pos) => Ok(Expr::False(pos)),
|
|
(Token::LexError(err), pos) => Err(ParseError::new(PERR::BadInput(err.to_string()), pos)),
|
|
(token, pos) => Err(ParseError::new(
|
|
PERR::BadInput(format!("Unexpected '{}'", token.syntax())),
|
|
pos,
|
|
)),
|
|
}?;
|
|
|
|
if can_be_indexed {
|
|
// Tail processing all possible indexing
|
|
#[cfg(not(feature = "no_index"))]
|
|
while let Some((Token::LeftBracket, pos)) = input.peek() {
|
|
let pos = *pos;
|
|
input.next();
|
|
root_expr = parse_index_expr(Box::new(root_expr), input, pos, allow_stmt_expr)?;
|
|
}
|
|
}
|
|
|
|
Ok(root_expr)
|
|
}
|
|
|
|
/// Parse a potential unary operator.
|
|
fn parse_unary<'a>(
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
allow_stmt_expr: bool,
|
|
) -> Result<Expr, ParseError> {
|
|
match input
|
|
.peek()
|
|
.ok_or_else(|| ParseError::new(PERR::UnexpectedEOF, Position::eof()))?
|
|
{
|
|
// -expr
|
|
(Token::UnaryMinus, pos) => {
|
|
let pos = *pos;
|
|
|
|
input.next();
|
|
|
|
match parse_unary(input, allow_stmt_expr)? {
|
|
// Negative integer
|
|
Expr::IntegerConstant(i, _) => i
|
|
.checked_neg()
|
|
.map(|x| Expr::IntegerConstant(x, pos))
|
|
.or_else(|| {
|
|
#[cfg(not(feature = "no_float"))]
|
|
return Some(Expr::FloatConstant(-(i as FLOAT), pos));
|
|
|
|
#[cfg(feature = "no_float")]
|
|
return None;
|
|
})
|
|
.ok_or_else(|| {
|
|
ParseError::new(
|
|
PERR::BadInput(LERR::MalformedNumber(format!("-{}", i)).to_string()),
|
|
pos,
|
|
)
|
|
}),
|
|
|
|
// Negative float
|
|
#[cfg(not(feature = "no_float"))]
|
|
Expr::FloatConstant(f, pos) => Ok(Expr::FloatConstant(-f, pos)),
|
|
|
|
// Call negative function
|
|
expr => Ok(Expr::FunctionCall("-".into(), vec![expr], None, pos)),
|
|
}
|
|
}
|
|
// +expr
|
|
(Token::UnaryPlus, _) => {
|
|
input.next();
|
|
parse_unary(input, allow_stmt_expr)
|
|
}
|
|
// !expr
|
|
(Token::Bang, pos) => {
|
|
let pos = *pos;
|
|
|
|
input.next();
|
|
|
|
Ok(Expr::FunctionCall(
|
|
"!".into(),
|
|
vec![parse_primary(input, allow_stmt_expr)?],
|
|
Some(Box::new(false)), // NOT operator, when operating on invalid operand, defaults to false
|
|
pos,
|
|
))
|
|
}
|
|
// All other tokens
|
|
_ => parse_primary(input, allow_stmt_expr),
|
|
}
|
|
}
|
|
|
|
/// Parse an assignment.
|
|
fn parse_assignment(lhs: Expr, rhs: Expr, pos: Position) -> Result<Expr, ParseError> {
|
|
// Is the LHS in a valid format for an assignment target?
|
|
fn valid_assignment_chain(expr: &Expr, is_top: bool) -> Option<ParseError> {
|
|
match expr {
|
|
// var
|
|
Expr::Variable(_, _) => {
|
|
assert!(is_top, "property expected but gets variable");
|
|
None
|
|
}
|
|
// property
|
|
Expr::Property(_, _) => {
|
|
assert!(!is_top, "variable expected but gets property");
|
|
None
|
|
}
|
|
|
|
// var[...]
|
|
#[cfg(not(feature = "no_index"))]
|
|
Expr::Index(idx_lhs, _, _) if matches!(idx_lhs.as_ref(), &Expr::Variable(_, _)) => {
|
|
assert!(is_top, "property expected but gets variable");
|
|
None
|
|
}
|
|
// property[...]
|
|
#[cfg(not(feature = "no_index"))]
|
|
Expr::Index(idx_lhs, _, _) if matches!(idx_lhs.as_ref(), &Expr::Property(_, _)) => {
|
|
assert!(!is_top, "variable expected but gets property");
|
|
None
|
|
}
|
|
|
|
// idx_lhs[...]
|
|
#[cfg(not(feature = "no_index"))]
|
|
Expr::Index(idx_lhs, _, pos) => Some(ParseError::new(
|
|
match idx_lhs.as_ref() {
|
|
Expr::Index(_, _, _) => ParseErrorType::AssignmentToCopy,
|
|
_ => ParseErrorType::AssignmentToInvalidLHS,
|
|
},
|
|
*pos,
|
|
)),
|
|
|
|
// dot_lhs.dot_rhs
|
|
Expr::Dot(dot_lhs, dot_rhs, _) => match dot_lhs.as_ref() {
|
|
// var.dot_rhs
|
|
Expr::Variable(_, _) if is_top => valid_assignment_chain(dot_rhs, false),
|
|
// property.dot_rhs
|
|
Expr::Property(_, _) if !is_top => valid_assignment_chain(dot_rhs, false),
|
|
// var[...]
|
|
#[cfg(not(feature = "no_index"))]
|
|
Expr::Index(idx_lhs, _, _)
|
|
if matches!(idx_lhs.as_ref(), &Expr::Variable(_, _)) && is_top =>
|
|
{
|
|
valid_assignment_chain(dot_rhs, false)
|
|
}
|
|
// property[...]
|
|
#[cfg(not(feature = "no_index"))]
|
|
Expr::Index(idx_lhs, _, _)
|
|
if matches!(idx_lhs.as_ref(), &Expr::Property(_, _)) && !is_top =>
|
|
{
|
|
valid_assignment_chain(dot_rhs, false)
|
|
}
|
|
// idx_lhs[...]
|
|
#[cfg(not(feature = "no_index"))]
|
|
Expr::Index(idx_lhs, _, _) => Some(ParseError::new(
|
|
ParseErrorType::AssignmentToCopy,
|
|
idx_lhs.position(),
|
|
)),
|
|
|
|
expr => panic!("unexpected dot expression {:#?}", expr),
|
|
},
|
|
|
|
_ => Some(ParseError::new(
|
|
ParseErrorType::AssignmentToInvalidLHS,
|
|
expr.position(),
|
|
)),
|
|
}
|
|
}
|
|
|
|
match valid_assignment_chain(&lhs, true) {
|
|
None => Ok(Expr::Assignment(Box::new(lhs), Box::new(rhs), pos)),
|
|
Some(err) => Err(err),
|
|
}
|
|
}
|
|
|
|
/// Parse an operator-assignment expression.
|
|
fn parse_op_assignment(op: &str, lhs: Expr, rhs: Expr, pos: Position) -> Result<Expr, ParseError> {
|
|
let lhs_copy = lhs.clone();
|
|
|
|
// lhs op= rhs -> lhs = op(lhs, rhs)
|
|
parse_assignment(
|
|
lhs,
|
|
Expr::FunctionCall(op.into(), vec![lhs_copy, rhs], None, pos),
|
|
pos,
|
|
)
|
|
}
|
|
|
|
/// Parse a binary expression.
|
|
fn parse_binary_op<'a>(
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
parent_precedence: u8,
|
|
lhs: Expr,
|
|
allow_stmt_expr: bool,
|
|
) -> Result<Expr, ParseError> {
|
|
let mut current_lhs = lhs;
|
|
|
|
loop {
|
|
let (current_precedence, bind_right) = if let Some((ref current_op, _)) = input.peek() {
|
|
(current_op.precedence(), current_op.is_bind_right())
|
|
} else {
|
|
(0, false)
|
|
};
|
|
|
|
// Bind left to the parent lhs expression if precedence is higher
|
|
// If same precedence, then check if the operator binds right
|
|
if current_precedence < parent_precedence
|
|
|| (current_precedence == parent_precedence && !bind_right)
|
|
{
|
|
return Ok(current_lhs);
|
|
}
|
|
|
|
if let Some((op_token, pos)) = input.next() {
|
|
input.peek();
|
|
|
|
let rhs = parse_unary(input, allow_stmt_expr)?;
|
|
|
|
let next_precedence = if let Some((next_op, _)) = input.peek() {
|
|
next_op.precedence()
|
|
} else {
|
|
0
|
|
};
|
|
|
|
// Bind to right if the next operator has higher precedence
|
|
// If same precedence, then check if the operator binds right
|
|
let rhs = if (current_precedence == next_precedence && bind_right)
|
|
|| current_precedence < next_precedence
|
|
{
|
|
parse_binary_op(input, current_precedence, rhs, allow_stmt_expr)?
|
|
} else {
|
|
// Otherwise bind to left (even if next operator has the same precedence)
|
|
rhs
|
|
};
|
|
|
|
current_lhs = match op_token {
|
|
Token::Plus => Expr::FunctionCall("+".into(), vec![current_lhs, rhs], None, pos),
|
|
Token::Minus => Expr::FunctionCall("-".into(), vec![current_lhs, rhs], None, pos),
|
|
Token::Multiply => {
|
|
Expr::FunctionCall("*".into(), vec![current_lhs, rhs], None, pos)
|
|
}
|
|
Token::Divide => Expr::FunctionCall("/".into(), vec![current_lhs, rhs], None, pos),
|
|
|
|
Token::Equals => parse_assignment(current_lhs, rhs, pos)?,
|
|
Token::PlusAssign => parse_op_assignment("+", current_lhs, rhs, pos)?,
|
|
Token::MinusAssign => parse_op_assignment("-", current_lhs, rhs, pos)?,
|
|
|
|
Token::Period => {
|
|
fn change_var_to_property(expr: Expr) -> Expr {
|
|
match expr {
|
|
Expr::Dot(lhs, rhs, pos) => Expr::Dot(
|
|
Box::new(change_var_to_property(*lhs)),
|
|
Box::new(change_var_to_property(*rhs)),
|
|
pos,
|
|
),
|
|
#[cfg(not(feature = "no_index"))]
|
|
Expr::Index(lhs, idx, pos) => {
|
|
Expr::Index(Box::new(change_var_to_property(*lhs)), idx, pos)
|
|
}
|
|
Expr::Variable(s, pos) => Expr::Property(s, pos),
|
|
expr => expr,
|
|
}
|
|
}
|
|
|
|
Expr::Dot(
|
|
Box::new(current_lhs),
|
|
Box::new(change_var_to_property(rhs)),
|
|
pos,
|
|
)
|
|
}
|
|
|
|
// Comparison operators default to false when passed invalid operands
|
|
Token::EqualsTo => Expr::FunctionCall(
|
|
"==".into(),
|
|
vec![current_lhs, rhs],
|
|
Some(Box::new(false)),
|
|
pos,
|
|
),
|
|
Token::NotEqualsTo => Expr::FunctionCall(
|
|
"!=".into(),
|
|
vec![current_lhs, rhs],
|
|
Some(Box::new(false)),
|
|
pos,
|
|
),
|
|
Token::LessThan => Expr::FunctionCall(
|
|
"<".into(),
|
|
vec![current_lhs, rhs],
|
|
Some(Box::new(false)),
|
|
pos,
|
|
),
|
|
Token::LessThanEqualsTo => Expr::FunctionCall(
|
|
"<=".into(),
|
|
vec![current_lhs, rhs],
|
|
Some(Box::new(false)),
|
|
pos,
|
|
),
|
|
Token::GreaterThan => Expr::FunctionCall(
|
|
">".into(),
|
|
vec![current_lhs, rhs],
|
|
Some(Box::new(false)),
|
|
pos,
|
|
),
|
|
Token::GreaterThanEqualsTo => Expr::FunctionCall(
|
|
">=".into(),
|
|
vec![current_lhs, rhs],
|
|
Some(Box::new(false)),
|
|
pos,
|
|
),
|
|
|
|
Token::Or => Expr::Or(Box::new(current_lhs), Box::new(rhs)),
|
|
Token::And => Expr::And(Box::new(current_lhs), Box::new(rhs)),
|
|
Token::XOr => Expr::FunctionCall("^".into(), vec![current_lhs, rhs], None, pos),
|
|
Token::OrAssign => parse_op_assignment("|", current_lhs, rhs, pos)?,
|
|
Token::AndAssign => parse_op_assignment("&", current_lhs, rhs, pos)?,
|
|
Token::XOrAssign => parse_op_assignment("^", current_lhs, rhs, pos)?,
|
|
Token::MultiplyAssign => parse_op_assignment("*", current_lhs, rhs, pos)?,
|
|
Token::DivideAssign => parse_op_assignment("/", current_lhs, rhs, pos)?,
|
|
Token::Pipe => Expr::FunctionCall("|".into(), vec![current_lhs, rhs], None, pos),
|
|
Token::LeftShift => {
|
|
Expr::FunctionCall("<<".into(), vec![current_lhs, rhs], None, pos)
|
|
}
|
|
Token::RightShift => {
|
|
Expr::FunctionCall(">>".into(), vec![current_lhs, rhs], None, pos)
|
|
}
|
|
Token::LeftShiftAssign => parse_op_assignment("<<", current_lhs, rhs, pos)?,
|
|
Token::RightShiftAssign => parse_op_assignment(">>", current_lhs, rhs, pos)?,
|
|
Token::Ampersand => {
|
|
Expr::FunctionCall("&".into(), vec![current_lhs, rhs], None, pos)
|
|
}
|
|
Token::Modulo => Expr::FunctionCall("%".into(), vec![current_lhs, rhs], None, pos),
|
|
Token::ModuloAssign => parse_op_assignment("%", current_lhs, rhs, pos)?,
|
|
Token::PowerOf => Expr::FunctionCall("~".into(), vec![current_lhs, rhs], None, pos),
|
|
Token::PowerOfAssign => parse_op_assignment("~", current_lhs, rhs, pos)?,
|
|
token => {
|
|
return Err(ParseError::new(
|
|
PERR::UnknownOperator(token.syntax().into()),
|
|
pos,
|
|
))
|
|
}
|
|
};
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Parse an expression.
|
|
fn parse_expr<'a>(
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
allow_stmt_expr: bool,
|
|
) -> Result<Expr, ParseError> {
|
|
let lhs = parse_unary(input, allow_stmt_expr)?;
|
|
parse_binary_op(input, 1, lhs, allow_stmt_expr)
|
|
}
|
|
|
|
/// Make sure that the expression is not a statement expression (i.e. wrapped in {})
|
|
fn ensure_not_statement_expr<'a>(
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
type_name: &str,
|
|
) -> Result<(), ParseError> {
|
|
match input
|
|
.peek()
|
|
.ok_or_else(|| ParseError(PERR::ExprExpected(type_name.to_string()), Position::eof()))?
|
|
{
|
|
// Disallow statement expressions
|
|
(Token::LeftBrace, pos) => Err(ParseError(PERR::ExprExpected(type_name.to_string()), *pos)),
|
|
// No need to check for others at this time - leave it for the expr parser
|
|
_ => Ok(()),
|
|
}
|
|
}
|
|
|
|
/// Parse an if statement.
|
|
fn parse_if<'a>(
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
breakable: bool,
|
|
allow_stmt_expr: bool,
|
|
) -> Result<Stmt, ParseError> {
|
|
// if ...
|
|
input.next();
|
|
|
|
// if guard { if_body }
|
|
ensure_not_statement_expr(input, "a boolean")?;
|
|
let guard = parse_expr(input, allow_stmt_expr)?;
|
|
let if_body = parse_block(input, breakable, allow_stmt_expr)?;
|
|
|
|
// if guard { if_body } else ...
|
|
let else_body = if matches!(input.peek(), Some((Token::Else, _))) {
|
|
input.next();
|
|
|
|
Some(Box::new(if matches!(input.peek(), Some((Token::If, _))) {
|
|
// if guard { if_body } else if ...
|
|
parse_if(input, breakable, allow_stmt_expr)?
|
|
} else {
|
|
// if guard { if_body } else { else-body }
|
|
parse_block(input, breakable, allow_stmt_expr)?
|
|
}))
|
|
} else {
|
|
None
|
|
};
|
|
|
|
Ok(Stmt::IfThenElse(
|
|
Box::new(guard),
|
|
Box::new(if_body),
|
|
else_body,
|
|
))
|
|
}
|
|
|
|
/// Parse a while loop.
|
|
fn parse_while<'a>(
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
allow_stmt_expr: bool,
|
|
) -> Result<Stmt, ParseError> {
|
|
// while ...
|
|
input.next();
|
|
|
|
// while guard { body }
|
|
ensure_not_statement_expr(input, "a boolean")?;
|
|
let guard = parse_expr(input, allow_stmt_expr)?;
|
|
let body = parse_block(input, true, allow_stmt_expr)?;
|
|
|
|
Ok(Stmt::While(Box::new(guard), Box::new(body)))
|
|
}
|
|
|
|
/// Parse a loop statement.
|
|
fn parse_loop<'a>(
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
allow_stmt_expr: bool,
|
|
) -> Result<Stmt, ParseError> {
|
|
// loop ...
|
|
input.next();
|
|
|
|
// loop { body }
|
|
let body = parse_block(input, true, allow_stmt_expr)?;
|
|
|
|
Ok(Stmt::Loop(Box::new(body)))
|
|
}
|
|
|
|
/// Parse a for loop.
|
|
fn parse_for<'a>(
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
allow_stmt_expr: bool,
|
|
) -> Result<Stmt, ParseError> {
|
|
// for ...
|
|
input.next();
|
|
|
|
// for name ...
|
|
let name = match input
|
|
.next()
|
|
.ok_or_else(|| ParseError::new(PERR::VariableExpected, Position::eof()))?
|
|
{
|
|
// Variable name
|
|
(Token::Identifier(s), _) => s,
|
|
// Bad identifier
|
|
(Token::LexError(err), pos) => {
|
|
return Err(ParseError::new(PERR::BadInput(err.to_string()), pos))
|
|
}
|
|
// Not a variable name
|
|
(_, pos) => return Err(ParseError::new(PERR::VariableExpected, pos)),
|
|
};
|
|
|
|
// for name in ...
|
|
match input
|
|
.next()
|
|
.ok_or_else(|| ParseError::new(PERR::MissingIn, Position::eof()))?
|
|
{
|
|
(Token::In, _) => (),
|
|
(_, pos) => return Err(ParseError::new(PERR::MissingIn, pos)),
|
|
}
|
|
|
|
// for name in expr { body }
|
|
ensure_not_statement_expr(input, "a boolean")?;
|
|
let expr = parse_expr(input, allow_stmt_expr)?;
|
|
let body = parse_block(input, true, allow_stmt_expr)?;
|
|
|
|
Ok(Stmt::For(name, Box::new(expr), Box::new(body)))
|
|
}
|
|
|
|
/// Parse a variable definition statement.
|
|
fn parse_let<'a>(
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
var_type: VariableType,
|
|
allow_stmt_expr: bool,
|
|
) -> Result<Stmt, ParseError> {
|
|
// let/const... (specified in `var_type`)
|
|
input.next();
|
|
|
|
// let name ...
|
|
let (name, pos) = match input
|
|
.next()
|
|
.ok_or_else(|| ParseError::new(PERR::VariableExpected, Position::eof()))?
|
|
{
|
|
(Token::Identifier(s), pos) => (s, pos),
|
|
(Token::LexError(err), pos) => {
|
|
return Err(ParseError::new(PERR::BadInput(err.to_string()), pos))
|
|
}
|
|
(_, pos) => return Err(ParseError::new(PERR::VariableExpected, pos)),
|
|
};
|
|
|
|
// let name = ...
|
|
if matches!(input.peek(), Some((Token::Equals, _))) {
|
|
input.next();
|
|
|
|
// let name = expr
|
|
let init_value = parse_expr(input, allow_stmt_expr)?;
|
|
|
|
match var_type {
|
|
// let name = expr
|
|
VariableType::Normal => Ok(Stmt::Let(name, Some(Box::new(init_value)), pos)),
|
|
// const name = { expr:constant }
|
|
VariableType::Constant if init_value.is_constant() => {
|
|
Ok(Stmt::Const(name, Box::new(init_value), pos))
|
|
}
|
|
// const name = expr - error
|
|
VariableType::Constant => Err(ParseError(
|
|
PERR::ForbiddenConstantExpr(name.to_string()),
|
|
init_value.position(),
|
|
)),
|
|
}
|
|
} else {
|
|
// let name
|
|
Ok(Stmt::Let(name, None, pos))
|
|
}
|
|
}
|
|
|
|
/// Parse a statement block.
|
|
fn parse_block<'a>(
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
breakable: bool,
|
|
allow_stmt_expr: bool,
|
|
) -> Result<Stmt, ParseError> {
|
|
// Must start with {
|
|
let pos = match input
|
|
.next()
|
|
.ok_or_else(|| ParseError::new(PERR::MissingLeftBrace, Position::eof()))?
|
|
{
|
|
(Token::LeftBrace, pos) => pos,
|
|
(_, pos) => return Err(ParseError::new(PERR::MissingLeftBrace, pos)),
|
|
};
|
|
|
|
let mut statements = Vec::new();
|
|
|
|
while !matches!(input.peek(), Some((Token::RightBrace, _))) {
|
|
// Parse statements inside the block
|
|
let stmt = parse_stmt(input, breakable, allow_stmt_expr)?;
|
|
|
|
// See if it needs a terminating semicolon
|
|
let need_semicolon = !stmt.is_self_terminated();
|
|
|
|
statements.push(stmt);
|
|
|
|
match input.peek() {
|
|
// EOF
|
|
None => break,
|
|
// { ... stmt }
|
|
Some((Token::RightBrace, _)) => break,
|
|
// { ... stmt;
|
|
Some((Token::SemiColon, _)) if need_semicolon => {
|
|
input.next();
|
|
}
|
|
// { ... { stmt } ;
|
|
Some((Token::SemiColon, _)) if !need_semicolon => (),
|
|
// { ... { stmt } ???
|
|
Some((_, _)) if !need_semicolon => (),
|
|
// { ... stmt ??? - error
|
|
Some((_, pos)) => {
|
|
// Semicolons are not optional between statements
|
|
return Err(ParseError::new(
|
|
PERR::MissingSemicolon("terminating a statement".into()),
|
|
*pos,
|
|
));
|
|
}
|
|
}
|
|
}
|
|
|
|
match input.peek().ok_or_else(|| {
|
|
ParseError::new(
|
|
PERR::MissingRightBrace("end of block".into()),
|
|
Position::eof(),
|
|
)
|
|
})? {
|
|
(Token::RightBrace, _) => {
|
|
input.next();
|
|
Ok(Stmt::Block(statements, pos))
|
|
}
|
|
(_, pos) => Err(ParseError::new(
|
|
PERR::MissingRightBrace("end of block".into()),
|
|
*pos,
|
|
)),
|
|
}
|
|
}
|
|
|
|
/// Parse an expression as a statement.
|
|
fn parse_expr_stmt<'a>(
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
allow_stmt_expr: bool,
|
|
) -> Result<Stmt, ParseError> {
|
|
Ok(Stmt::Expr(Box::new(parse_expr(input, allow_stmt_expr)?)))
|
|
}
|
|
|
|
/// Parse a single statement.
|
|
fn parse_stmt<'a>(
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
breakable: bool,
|
|
allow_stmt_expr: bool,
|
|
) -> Result<Stmt, ParseError> {
|
|
let token = match input.peek() {
|
|
Some(token) => token,
|
|
None => return Ok(Stmt::Noop(Position::eof())),
|
|
};
|
|
|
|
match token {
|
|
// Semicolon - empty statement
|
|
(Token::SemiColon, pos) => Ok(Stmt::Noop(*pos)),
|
|
|
|
// fn ...
|
|
#[cfg(not(feature = "no_function"))]
|
|
(Token::Fn, pos) => return Err(ParseError::new(PERR::WrongFnDefinition, *pos)),
|
|
|
|
(Token::If, _) => parse_if(input, breakable, allow_stmt_expr),
|
|
(Token::While, _) => parse_while(input, allow_stmt_expr),
|
|
(Token::Loop, _) => parse_loop(input, allow_stmt_expr),
|
|
(Token::For, _) => parse_for(input, allow_stmt_expr),
|
|
(Token::Break, pos) if breakable => {
|
|
let pos = *pos;
|
|
input.next();
|
|
Ok(Stmt::Break(pos))
|
|
}
|
|
(Token::Break, pos) => return Err(ParseError::new(PERR::LoopBreak, *pos)),
|
|
(token @ Token::Return, pos) | (token @ Token::Throw, pos) => {
|
|
let return_type = match token {
|
|
Token::Return => ReturnType::Return,
|
|
Token::Throw => ReturnType::Exception,
|
|
_ => panic!("token should be return or throw"),
|
|
};
|
|
|
|
let pos = *pos;
|
|
input.next();
|
|
|
|
match input.peek() {
|
|
// `return`/`throw` at EOF
|
|
None => Ok(Stmt::ReturnWithVal(None, return_type, Position::eof())),
|
|
// `return;` or `throw;`
|
|
Some((Token::SemiColon, _)) => Ok(Stmt::ReturnWithVal(None, return_type, pos)),
|
|
// `return` or `throw` with expression
|
|
Some((_, _)) => {
|
|
let expr = parse_expr(input, allow_stmt_expr)?;
|
|
let pos = expr.position();
|
|
|
|
Ok(Stmt::ReturnWithVal(Some(Box::new(expr)), return_type, pos))
|
|
}
|
|
}
|
|
}
|
|
(Token::LeftBrace, _) => parse_block(input, breakable, allow_stmt_expr),
|
|
(Token::Let, _) => parse_let(input, VariableType::Normal, allow_stmt_expr),
|
|
(Token::Const, _) => parse_let(input, VariableType::Constant, allow_stmt_expr),
|
|
_ => parse_expr_stmt(input, allow_stmt_expr),
|
|
}
|
|
}
|
|
|
|
/// Parse a function definition.
|
|
#[cfg(not(feature = "no_function"))]
|
|
fn parse_fn<'a>(
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
allow_stmt_expr: bool,
|
|
) -> Result<FnDef, ParseError> {
|
|
let pos = input.next().expect("should be fn").1;
|
|
|
|
let name = match input
|
|
.next()
|
|
.ok_or_else(|| ParseError::new(PERR::FnMissingName, Position::eof()))?
|
|
{
|
|
(Token::Identifier(s), _) => s,
|
|
(_, pos) => return Err(ParseError::new(PERR::FnMissingName, pos)),
|
|
};
|
|
|
|
match input
|
|
.peek()
|
|
.ok_or_else(|| ParseError::new(PERR::FnMissingParams(name.clone()), Position::eof()))?
|
|
{
|
|
(Token::LeftParen, _) => {
|
|
input.next();
|
|
}
|
|
(_, pos) => return Err(ParseError::new(PERR::FnMissingParams(name), *pos)),
|
|
}
|
|
|
|
let mut params = Vec::new();
|
|
|
|
if matches!(input.peek(), Some((Token::RightParen, _))) {
|
|
input.next();
|
|
} else {
|
|
loop {
|
|
match input.next().ok_or_else(|| {
|
|
ParseError::new(
|
|
PERR::MissingRightParen(format!(
|
|
"closing the parameters list of function '{}'",
|
|
name
|
|
)),
|
|
Position::eof(),
|
|
)
|
|
})? {
|
|
(Token::Identifier(s), _) => {
|
|
params.push(s.into());
|
|
}
|
|
(_, pos) => {
|
|
return Err(ParseError::new(
|
|
PERR::MissingRightParen(format!(
|
|
"closing the parameters list of function '{}'",
|
|
name
|
|
)),
|
|
pos,
|
|
))
|
|
}
|
|
}
|
|
|
|
match input.next().ok_or_else(|| {
|
|
ParseError::new(
|
|
PERR::MissingRightParen(format!(
|
|
"closing the parameters list of function '{}'",
|
|
name
|
|
)),
|
|
Position::eof(),
|
|
)
|
|
})? {
|
|
(Token::RightParen, _) => break,
|
|
(Token::Comma, _) => (),
|
|
(Token::Identifier(_), _) => {
|
|
return Err(ParseError::new(
|
|
PERR::MissingComma(format!(
|
|
"separating the parameters of function '{}'",
|
|
name
|
|
)),
|
|
pos,
|
|
))
|
|
}
|
|
(_, pos) => {
|
|
return Err(ParseError::new(
|
|
PERR::MissingRightParen(format!(
|
|
"closing the parameters list of function '{}'",
|
|
name
|
|
)),
|
|
pos,
|
|
))
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
let body = match input.peek() {
|
|
Some((Token::LeftBrace, _)) => parse_block(input, false, allow_stmt_expr)?,
|
|
Some((_, pos)) => return Err(ParseError::new(PERR::FnMissingBody(name), *pos)),
|
|
None => return Err(ParseError::new(PERR::FnMissingBody(name), Position::eof())),
|
|
};
|
|
|
|
Ok(FnDef {
|
|
name,
|
|
params,
|
|
body,
|
|
pos,
|
|
})
|
|
}
|
|
|
|
pub fn parse_global_expr<'a, 'e>(
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
engine: &Engine<'e>,
|
|
scope: &Scope,
|
|
) -> Result<AST, ParseError> {
|
|
let expr = parse_expr(input, false)?;
|
|
|
|
if let Some((token, pos)) = input.peek() {
|
|
// Return error if the expression doesn't end
|
|
return Err(ParseError::new(
|
|
PERR::BadInput(format!("Unexpected '{}'", token.syntax())),
|
|
*pos,
|
|
));
|
|
}
|
|
|
|
Ok(
|
|
// Optimize AST
|
|
#[cfg(not(feature = "no_optimize"))]
|
|
optimize_into_ast(engine, scope, vec![Stmt::Expr(Box::new(expr))], vec![]),
|
|
//
|
|
// Do not optimize AST if `no_optimize`
|
|
#[cfg(feature = "no_optimize")]
|
|
AST(vec![Stmt::Expr(Box::new(expr))], vec![]),
|
|
)
|
|
}
|
|
|
|
/// Parse the global level statements.
|
|
fn parse_global_level<'a>(
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
) -> Result<(Vec<Stmt>, Vec<FnDef>), ParseError> {
|
|
let mut statements = Vec::<Stmt>::new();
|
|
let mut functions = Vec::<FnDef>::new();
|
|
|
|
while input.peek().is_some() {
|
|
#[cfg(not(feature = "no_function"))]
|
|
{
|
|
// Collect all the function definitions
|
|
if matches!(input.peek().expect("should not be None"), (Token::Fn, _)) {
|
|
let f = parse_fn(input, true)?;
|
|
|
|
// Ensure list is sorted
|
|
match functions.binary_search_by(|fn_def| fn_def.compare(&f.name, f.params.len())) {
|
|
Ok(n) => functions[n] = f, // Override previous definition
|
|
Err(n) => functions.insert(n, f), // New function definition
|
|
}
|
|
|
|
continue;
|
|
}
|
|
}
|
|
|
|
// Actual statement
|
|
let stmt = parse_stmt(input, false, true)?;
|
|
|
|
let need_semicolon = !stmt.is_self_terminated();
|
|
|
|
statements.push(stmt);
|
|
|
|
match input.peek() {
|
|
// EOF
|
|
None => break,
|
|
// stmt ;
|
|
Some((Token::SemiColon, _)) if need_semicolon => {
|
|
input.next();
|
|
}
|
|
// stmt ;
|
|
Some((Token::SemiColon, _)) if !need_semicolon => (),
|
|
// { stmt } ???
|
|
Some((_, _)) if !need_semicolon => (),
|
|
// stmt ??? - error
|
|
Some((_, pos)) => {
|
|
// Semicolons are not optional between statements
|
|
return Err(ParseError::new(
|
|
PERR::MissingSemicolon("terminating a statement".into()),
|
|
*pos,
|
|
));
|
|
}
|
|
}
|
|
}
|
|
|
|
Ok((statements, functions))
|
|
}
|
|
|
|
/// Run the parser on an input stream, returning an AST.
|
|
pub fn parse<'a, 'e>(
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
engine: &Engine<'e>,
|
|
scope: &Scope,
|
|
) -> Result<AST, ParseError> {
|
|
let (statements, functions) = parse_global_level(input)?;
|
|
|
|
Ok(
|
|
// Optimize AST
|
|
#[cfg(not(feature = "no_optimize"))]
|
|
optimize_into_ast(engine, scope, statements, functions),
|
|
//
|
|
// Do not optimize AST if `no_optimize`
|
|
#[cfg(feature = "no_optimize")]
|
|
AST(statements, functions.into_iter().map(Arc::new).collect()),
|
|
)
|
|
}
|
|
|
|
/// Map a `Dynamic` value to an expression.
|
|
///
|
|
/// Returns Some(expression) if conversion is successful. Otherwise None.
|
|
pub fn map_dynamic_to_expr(value: Dynamic, pos: Position) -> (Option<Expr>, Dynamic) {
|
|
if value.is::<INT>() {
|
|
let value2 = value.clone();
|
|
(
|
|
Some(Expr::IntegerConstant(
|
|
*value.downcast::<INT>().expect("value should be INT"),
|
|
pos,
|
|
)),
|
|
value2,
|
|
)
|
|
} else if value.is::<char>() {
|
|
let value2 = value.clone();
|
|
(
|
|
Some(Expr::CharConstant(
|
|
*value.downcast::<char>().expect("value should be char"),
|
|
pos,
|
|
)),
|
|
value2,
|
|
)
|
|
} else if value.is::<String>() {
|
|
let value2 = value.clone();
|
|
(
|
|
Some(Expr::StringConstant(
|
|
*value.downcast::<String>().expect("value should be String"),
|
|
pos,
|
|
)),
|
|
value2,
|
|
)
|
|
} else if value.is::<bool>() {
|
|
let value2 = value.clone();
|
|
(
|
|
Some(
|
|
if *value.downcast::<bool>().expect("value should be bool") {
|
|
Expr::True(pos)
|
|
} else {
|
|
Expr::False(pos)
|
|
},
|
|
),
|
|
value2,
|
|
)
|
|
} else {
|
|
#[cfg(not(feature = "no_float"))]
|
|
{
|
|
if value.is::<FLOAT>() {
|
|
let value2 = value.clone();
|
|
return (
|
|
Some(Expr::FloatConstant(
|
|
*value.downcast::<FLOAT>().expect("value should be FLOAT"),
|
|
pos,
|
|
)),
|
|
value2,
|
|
);
|
|
}
|
|
}
|
|
|
|
(None, value)
|
|
}
|
|
}
|