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rhai/src/ast.rs
Stephen Chung b9de8eaa7f Minor code refactor.
2020-11-02 23:54:19 +08:00

1243 lines
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//! Module defining the AST (abstract syntax tree).
use crate::dynamic::{Dynamic, Union};
use crate::fn_native::{FnPtr, Shared};
use crate::module::{Module, ModuleRef};
use crate::syntax::FnCustomSyntaxEval;
use crate::token::{Position, Token};
use crate::utils::ImmutableString;
use crate::StaticVec;
use crate::INT;
#[cfg(not(feature = "no_float"))]
use crate::FLOAT;
#[cfg(not(feature = "no_index"))]
use crate::engine::Array;
#[cfg(not(feature = "no_object"))]
use crate::engine::{make_getter, make_setter, Map};
use crate::stdlib::{
any::TypeId,
borrow::Cow,
boxed::Box,
fmt,
hash::{Hash, Hasher},
num::NonZeroUsize,
ops::{Add, AddAssign},
string::String,
vec,
vec::Vec,
};
#[cfg(not(feature = "no_float"))]
use crate::stdlib::ops::Neg;
#[cfg(not(feature = "no_closure"))]
use crate::stdlib::collections::HashSet;
/// A type representing the access mode of a scripted function.
#[derive(Debug, Clone, Copy, Eq, PartialEq, Hash)]
pub enum FnAccess {
/// Public function.
Public,
/// Private function.
Private,
}
impl fmt::Display for FnAccess {
#[inline(always)]
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
Self::Private => write!(f, "private"),
Self::Public => write!(f, "public"),
}
}
}
impl FnAccess {
/// Is this access mode private?
#[inline(always)]
pub fn is_private(self) -> bool {
match self {
Self::Public => false,
Self::Private => true,
}
}
/// Is this access mode public?
#[inline(always)]
pub fn is_public(self) -> bool {
match self {
Self::Public => true,
Self::Private => false,
}
}
}
/// _[INTERNALS]_ A type containing information on a scripted function.
/// Exported under the `internals` feature only.
///
/// ## WARNING
///
/// This type is volatile and may change.
#[derive(Debug, Clone)]
pub struct ScriptFnDef {
/// Function name.
pub name: ImmutableString,
/// Function access mode.
pub access: FnAccess,
/// Names of function parameters.
pub params: StaticVec<String>,
/// Access to external variables.
#[cfg(not(feature = "no_closure"))]
pub externals: HashSet<String>,
/// Function body.
pub body: Stmt,
/// Position of the function definition.
pub pos: Position,
/// Encapsulated running environment, if any.
pub lib: Option<Shared<Module>>,
}
impl fmt::Display for ScriptFnDef {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(
f,
"{}{}({})",
if self.access.is_private() {
"private "
} else {
""
},
self.name,
self.params
.iter()
.map(|s| s.as_str())
.collect::<Vec<_>>()
.join(",")
)
}
}
/// Compiled AST (abstract syntax tree) of a Rhai script.
///
/// # Thread Safety
///
/// Currently, `AST` is neither `Send` nor `Sync`. Turn on the `sync` feature to make it `Send + Sync`.
#[derive(Debug, Clone, Default)]
pub struct AST(
/// Global statements.
Vec<Stmt>,
/// Script-defined functions.
Module,
);
impl AST {
/// Create a new `AST`.
#[inline(always)]
pub fn new(statements: Vec<Stmt>, lib: Module) -> Self {
Self(statements, lib)
}
/// Get the statements.
#[cfg(not(feature = "internals"))]
#[inline(always)]
pub(crate) fn statements(&self) -> &[Stmt] {
&self.0
}
/// _[INTERNALS]_ Get the statements.
/// Exported under the `internals` feature only.
#[cfg(feature = "internals")]
#[deprecated(note = "this method is volatile and may change")]
#[inline(always)]
pub fn statements(&self) -> &[Stmt] {
&self.0
}
/// Get a mutable reference to the statements.
#[cfg(not(feature = "no_optimize"))]
#[inline(always)]
pub(crate) fn statements_mut(&mut self) -> &mut Vec<Stmt> {
&mut self.0
}
/// Get the internal `Module` containing all script-defined functions.
#[cfg(not(feature = "internals"))]
#[inline(always)]
pub(crate) fn lib(&self) -> &Module {
&self.1
}
/// _[INTERNALS]_ Get the internal `Module` containing all script-defined functions.
/// Exported under the `internals` feature only.
#[cfg(feature = "internals")]
#[deprecated(note = "this method is volatile and may change")]
#[inline(always)]
pub fn lib(&self) -> &Module {
&self.1
}
/// Clone the `AST`'s functions into a new `AST`.
/// No statements are cloned.
///
/// This operation is cheap because functions are shared.
#[cfg(not(feature = "no_function"))]
#[inline(always)]
pub fn clone_functions_only(&self) -> Self {
self.clone_functions_only_filtered(|_, _, _| true)
}
/// Clone the `AST`'s functions into a new `AST` based on a filter predicate.
/// No statements are cloned.
///
/// This operation is cheap because functions are shared.
#[cfg(not(feature = "no_function"))]
#[inline(always)]
pub fn clone_functions_only_filtered(
&self,
mut filter: impl FnMut(FnAccess, &str, usize) -> bool,
) -> Self {
let mut functions: Module = Default::default();
functions.merge_filtered(&self.1, &mut filter);
Self(Default::default(), functions)
}
/// Clone the `AST`'s script statements into a new `AST`.
/// No functions are cloned.
#[inline(always)]
pub fn clone_statements_only(&self) -> Self {
Self(self.0.clone(), Default::default())
}
/// Merge two `AST` into one. Both `AST`'s are untouched and a new, merged, version
/// is returned.
///
/// Statements in the second `AST` are simply appended to the end of the first _without any processing_.
/// Thus, the return value of the first `AST` (if using expression-statement syntax) is buried.
/// Of course, if the first `AST` uses a `return` statement at the end, then
/// the second `AST` will essentially be dead code.
///
/// All script-defined functions in the second `AST` overwrite similarly-named functions
/// in the first `AST` with the same number of parameters.
///
/// # Example
///
/// ```
/// # fn main() -> Result<(), Box<rhai::EvalAltResult>> {
/// # #[cfg(not(feature = "no_function"))]
/// # {
/// use rhai::Engine;
///
/// let engine = Engine::new();
///
/// let ast1 = engine.compile(r#"
/// fn foo(x) { 42 + x }
/// foo(1)
/// "#)?;
///
/// let ast2 = engine.compile(r#"
/// fn foo(n) { "hello" + n }
/// foo("!")
/// "#)?;
///
/// let ast = ast1.merge(&ast2); // Merge 'ast2' into 'ast1'
///
/// // Notice that using the '+' operator also works:
/// // let ast = &ast1 + &ast2;
///
/// // 'ast' is essentially:
/// //
/// // fn foo(n) { "hello" + n } // <- definition of first 'foo' is overwritten
/// // foo(1) // <- notice this will be "hello1" instead of 43,
/// // // but it is no longer the return value
/// // foo("!") // returns "hello!"
///
/// // Evaluate it
/// assert_eq!(engine.eval_ast::<String>(&ast)?, "hello!");
/// # }
/// # Ok(())
/// # }
/// ```
#[inline(always)]
pub fn merge(&self, other: &Self) -> Self {
self.merge_filtered(other, |_, _, _| true)
}
/// Combine one `AST` with another. The second `AST` is consumed.
///
/// Statements in the second `AST` are simply appended to the end of the first _without any processing_.
/// Thus, the return value of the first `AST` (if using expression-statement syntax) is buried.
/// Of course, if the first `AST` uses a `return` statement at the end, then
/// the second `AST` will essentially be dead code.
///
/// All script-defined functions in the second `AST` overwrite similarly-named functions
/// in the first `AST` with the same number of parameters.
///
/// # Example
///
/// ```
/// # fn main() -> Result<(), Box<rhai::EvalAltResult>> {
/// # #[cfg(not(feature = "no_function"))]
/// # {
/// use rhai::Engine;
///
/// let engine = Engine::new();
///
/// let mut ast1 = engine.compile(r#"
/// fn foo(x) { 42 + x }
/// foo(1)
/// "#)?;
///
/// let ast2 = engine.compile(r#"
/// fn foo(n) { "hello" + n }
/// foo("!")
/// "#)?;
///
/// ast1.combine(ast2); // Combine 'ast2' into 'ast1'
///
/// // Notice that using the '+=' operator also works:
/// // ast1 += ast2;
///
/// // 'ast1' is essentially:
/// //
/// // fn foo(n) { "hello" + n } // <- definition of first 'foo' is overwritten
/// // foo(1) // <- notice this will be "hello1" instead of 43,
/// // // but it is no longer the return value
/// // foo("!") // returns "hello!"
///
/// // Evaluate it
/// assert_eq!(engine.eval_ast::<String>(&ast1)?, "hello!");
/// # }
/// # Ok(())
/// # }
/// ```
#[inline(always)]
pub fn combine(&mut self, other: Self) -> &mut Self {
self.combine_filtered(other, |_, _, _| true)
}
/// Merge two `AST` into one. Both `AST`'s are untouched and a new, merged, version
/// is returned.
///
/// Statements in the second `AST` are simply appended to the end of the first _without any processing_.
/// Thus, the return value of the first `AST` (if using expression-statement syntax) is buried.
/// Of course, if the first `AST` uses a `return` statement at the end, then
/// the second `AST` will essentially be dead code.
///
/// All script-defined functions in the second `AST` are first selected based on a filter
/// predicate, then overwrite similarly-named functions in the first `AST` with the
/// same number of parameters.
///
/// # Example
///
/// ```
/// # fn main() -> Result<(), Box<rhai::EvalAltResult>> {
/// # #[cfg(not(feature = "no_function"))]
/// # {
/// use rhai::Engine;
///
/// let engine = Engine::new();
///
/// let ast1 = engine.compile(r#"
/// fn foo(x) { 42 + x }
/// foo(1)
/// "#)?;
///
/// let ast2 = engine.compile(r#"
/// fn foo(n) { "hello" + n }
/// fn error() { 0 }
/// foo("!")
/// "#)?;
///
/// // Merge 'ast2', picking only 'error()' but not 'foo(_)', into 'ast1'
/// let ast = ast1.merge_filtered(&ast2, |_, name, params| name == "error" && params == 0);
///
/// // 'ast' is essentially:
/// //
/// // fn foo(n) { 42 + n } // <- definition of 'ast1::foo' is not overwritten
/// // // because 'ast2::foo' is filtered away
/// // foo(1) // <- notice this will be 43 instead of "hello1",
/// // // but it is no longer the return value
/// // fn error() { 0 } // <- this function passes the filter and is merged
/// // foo("!") // <- returns "42!"
///
/// // Evaluate it
/// assert_eq!(engine.eval_ast::<String>(&ast)?, "42!");
/// # }
/// # Ok(())
/// # }
/// ```
#[inline]
pub fn merge_filtered(
&self,
other: &Self,
mut filter: impl FnMut(FnAccess, &str, usize) -> bool,
) -> Self {
let Self(statements, functions) = self;
let ast = match (statements.is_empty(), other.0.is_empty()) {
(false, false) => {
let mut statements = statements.clone();
statements.extend(other.0.iter().cloned());
statements
}
(false, true) => statements.clone(),
(true, false) => other.0.clone(),
(true, true) => vec![],
};
let mut functions = functions.clone();
functions.merge_filtered(&other.1, &mut filter);
Self::new(ast, functions)
}
/// Combine one `AST` with another. The second `AST` is consumed.
///
/// Statements in the second `AST` are simply appended to the end of the first _without any processing_.
/// Thus, the return value of the first `AST` (if using expression-statement syntax) is buried.
/// Of course, if the first `AST` uses a `return` statement at the end, then
/// the second `AST` will essentially be dead code.
///
/// All script-defined functions in the second `AST` are first selected based on a filter
/// predicate, then overwrite similarly-named functions in the first `AST` with the
/// same number of parameters.
///
/// # Example
///
/// ```
/// # fn main() -> Result<(), Box<rhai::EvalAltResult>> {
/// # #[cfg(not(feature = "no_function"))]
/// # {
/// use rhai::Engine;
///
/// let engine = Engine::new();
///
/// let mut ast1 = engine.compile(r#"
/// fn foo(x) { 42 + x }
/// foo(1)
/// "#)?;
///
/// let ast2 = engine.compile(r#"
/// fn foo(n) { "hello" + n }
/// fn error() { 0 }
/// foo("!")
/// "#)?;
///
/// // Combine 'ast2', picking only 'error()' but not 'foo(_)', into 'ast1'
/// ast1.combine_filtered(ast2, |_, name, params| name == "error" && params == 0);
///
/// // 'ast1' is essentially:
/// //
/// // fn foo(n) { 42 + n } // <- definition of 'ast1::foo' is not overwritten
/// // // because 'ast2::foo' is filtered away
/// // foo(1) // <- notice this will be 43 instead of "hello1",
/// // // but it is no longer the return value
/// // fn error() { 0 } // <- this function passes the filter and is merged
/// // foo("!") // <- returns "42!"
///
/// // Evaluate it
/// assert_eq!(engine.eval_ast::<String>(&ast1)?, "42!");
/// # }
/// # Ok(())
/// # }
/// ```
#[inline(always)]
pub fn combine_filtered(
&mut self,
other: Self,
mut filter: impl FnMut(FnAccess, &str, usize) -> bool,
) -> &mut Self {
let Self(ref mut statements, ref mut functions) = self;
statements.extend(other.0.into_iter());
functions.merge_filtered(&other.1, &mut filter);
self
}
/// Filter out the functions, retaining only some based on a filter predicate.
///
/// # Example
///
/// ```
/// # fn main() -> Result<(), Box<rhai::EvalAltResult>> {
/// # #[cfg(not(feature = "no_function"))]
/// # {
/// use rhai::Engine;
///
/// let engine = Engine::new();
///
/// let mut ast = engine.compile(r#"
/// fn foo(n) { n + 1 }
/// fn bar() { print("hello"); }
/// "#)?;
///
/// // Remove all functions except 'foo(_)'
/// ast.retain_functions(|_, name, params| name == "foo" && params == 1);
/// # }
/// # Ok(())
/// # }
/// ```
#[cfg(not(feature = "no_function"))]
#[inline(always)]
pub fn retain_functions(&mut self, filter: impl FnMut(FnAccess, &str, usize) -> bool) {
self.1.retain_functions(filter);
}
/// Iterate through all functions
#[cfg(not(feature = "no_function"))]
#[inline(always)]
pub fn iter_functions<'a>(
&'a self,
) -> impl Iterator<Item = (FnAccess, &str, usize, Shared<ScriptFnDef>)> + 'a {
self.1.iter_script_fn()
}
/// Clear all function definitions in the `AST`.
#[cfg(not(feature = "no_function"))]
#[inline(always)]
pub fn clear_functions(&mut self) {
self.1 = Default::default();
}
/// Clear all statements in the `AST`, leaving only function definitions.
#[inline(always)]
pub fn clear_statements(&mut self) {
self.0 = vec![];
}
}
impl<A: AsRef<AST>> Add<A> for &AST {
type Output = AST;
#[inline(always)]
fn add(self, rhs: A) -> Self::Output {
self.merge(rhs.as_ref())
}
}
impl<A: Into<AST>> AddAssign<A> for AST {
#[inline(always)]
fn add_assign(&mut self, rhs: A) {
self.combine(rhs.into());
}
}
impl AsRef<[Stmt]> for AST {
#[inline(always)]
fn as_ref(&self) -> &[Stmt] {
self.statements()
}
}
impl AsRef<Module> for AST {
#[inline(always)]
fn as_ref(&self) -> &Module {
self.lib()
}
}
/// An identifier containing a string name and a position.
#[derive(Debug, Clone, Eq, PartialEq, Hash)]
pub struct Ident {
pub name: String,
pub pos: Position,
}
impl Ident {
/// Create a new `Identifier`.
pub fn new(name: String, pos: Position) -> Self {
Self { name, pos }
}
}
/// An identifier containing an immutable name and a position.
#[derive(Debug, Clone, Eq, PartialEq, Hash)]
pub struct IdentX {
pub name: ImmutableString,
pub pos: Position,
}
impl From<Ident> for IdentX {
fn from(value: Ident) -> Self {
Self {
name: value.name.into(),
pos: value.pos,
}
}
}
impl IdentX {
/// Create a new `Identifier`.
pub fn new(name: impl Into<ImmutableString>, pos: Position) -> Self {
Self {
name: name.into(),
pos,
}
}
}
/// _[INTERNALS]_ A type encapsulating the mode of a `return`/`throw` statement.
/// Exported under the `internals` feature only.
///
/// ## WARNING
///
/// This type is volatile and may change.
#[derive(Debug, Eq, PartialEq, Clone, Copy, Hash)]
pub enum ReturnType {
/// `return` statement.
Return,
/// `throw` statement.
Exception,
}
/// _[INTERNALS]_ A Rhai statement.
/// Exported under the `internals` feature only.
///
/// Each variant is at most one pointer in size (for speed),
/// with everything being allocated together in one single tuple.
#[derive(Debug, Clone, Hash)]
pub enum Stmt {
/// No-op.
Noop(Position),
/// if expr { stmt } else { stmt }
IfThenElse(Expr, Box<(Stmt, Option<Stmt>)>, Position),
/// while expr { stmt }
While(Expr, Box<Stmt>, Position),
/// loop { stmt }
Loop(Box<Stmt>, Position),
/// for id in expr { stmt }
For(Expr, Box<(String, Stmt)>, Position),
/// let id = expr
Let(Box<Ident>, Option<Expr>, Position),
/// const id = expr
Const(Box<Ident>, Option<Expr>, Position),
/// expr op= expr
Assignment(Box<(Expr, Cow<'static, str>, Expr)>, Position),
/// { stmt; ... }
Block(Vec<Stmt>, Position),
/// try { stmt; ... } catch ( var ) { stmt; ... }
TryCatch(Box<(Stmt, Option<Ident>, Stmt, (Position, Position))>),
/// expr
Expr(Expr),
/// continue
Continue(Position),
/// break
Break(Position),
/// return/throw
ReturnWithVal((ReturnType, Position), Option<Expr>, Position),
/// import expr as var
#[cfg(not(feature = "no_module"))]
Import(Expr, Option<Box<IdentX>>, Position),
/// export var as var, ...
#[cfg(not(feature = "no_module"))]
Export(Vec<(Ident, Option<Ident>)>, Position),
/// Convert a variable to shared.
#[cfg(not(feature = "no_closure"))]
Share(Box<Ident>),
}
impl Default for Stmt {
#[inline(always)]
fn default() -> Self {
Self::Noop(Default::default())
}
}
impl Stmt {
/// Is this statement `Noop`?
pub fn is_noop(&self) -> bool {
match self {
Self::Noop(_) => true,
_ => false,
}
}
/// Get the `Position` of this statement.
pub fn position(&self) -> Position {
match self {
Self::Noop(pos)
| Self::Continue(pos)
| Self::Break(pos)
| Self::Block(_, pos)
| Self::Assignment(_, pos)
| Self::IfThenElse(_, _, pos)
| Self::While(_, _, pos)
| Self::Loop(_, pos)
| Self::For(_, _, pos)
| Self::ReturnWithVal((_, pos), _, _) => *pos,
Self::Let(x, _, _) | Self::Const(x, _, _) => x.pos,
Self::TryCatch(x) => (x.3).0,
Self::Expr(x) => x.position(),
#[cfg(not(feature = "no_module"))]
Self::Import(_, _, pos) => *pos,
#[cfg(not(feature = "no_module"))]
Self::Export(_, pos) => *pos,
#[cfg(not(feature = "no_closure"))]
Self::Share(x) => x.pos,
}
}
/// Override the `Position` of this statement.
pub fn set_position(&mut self, new_pos: Position) -> &mut Self {
match self {
Self::Noop(pos)
| Self::Continue(pos)
| Self::Break(pos)
| Self::Block(_, pos)
| Self::Assignment(_, pos)
| Self::IfThenElse(_, _, pos)
| Self::While(_, _, pos)
| Self::Loop(_, pos)
| Self::For(_, _, pos)
| Self::ReturnWithVal((_, pos), _, _) => *pos = new_pos,
Self::Let(x, _, _) | Self::Const(x, _, _) => x.pos = new_pos,
Self::TryCatch(x) => (x.3).0 = new_pos,
Self::Expr(x) => {
x.set_position(new_pos);
}
#[cfg(not(feature = "no_module"))]
Self::Import(_, _, pos) => *pos = new_pos,
#[cfg(not(feature = "no_module"))]
Self::Export(_, pos) => *pos = new_pos,
#[cfg(not(feature = "no_closure"))]
Self::Share(x) => x.pos = new_pos,
}
self
}
/// Is this statement self-terminated (i.e. no need for a semicolon terminator)?
pub fn is_self_terminated(&self) -> bool {
match self {
Self::IfThenElse(_, _, _)
| Self::While(_, _, _)
| Self::Loop(_, _)
| Self::For(_, _, _)
| Self::Block(_, _)
| Self::TryCatch(_) => true,
// A No-op requires a semicolon in order to know it is an empty statement!
Self::Noop(_) => false,
Self::Let(_, _, _)
| Self::Const(_, _, _)
| Self::Assignment(_, _)
| Self::Expr(_)
| Self::Continue(_)
| Self::Break(_)
| Self::ReturnWithVal(_, _, _) => false,
#[cfg(not(feature = "no_module"))]
Self::Import(_, _, _) | Self::Export(_, _) => false,
#[cfg(not(feature = "no_closure"))]
Self::Share(_) => false,
}
}
/// Is this statement _pure_?
pub fn is_pure(&self) -> bool {
match self {
Self::Noop(_) => true,
Self::Expr(expr) => expr.is_pure(),
Self::IfThenElse(condition, x, _) if x.1.is_some() => {
condition.is_pure() && x.0.is_pure() && x.1.as_ref().unwrap().is_pure()
}
Self::IfThenElse(condition, x, _) => condition.is_pure() && x.0.is_pure(),
Self::While(condition, block, _) => condition.is_pure() && block.is_pure(),
Self::Loop(block, _) => block.is_pure(),
Self::For(iterable, x, _) => iterable.is_pure() && x.1.is_pure(),
Self::Let(_, _, _) | Self::Const(_, _, _) | Self::Assignment(_, _) => false,
Self::Block(block, _) => block.iter().all(|stmt| stmt.is_pure()),
Self::Continue(_) | Self::Break(_) | Self::ReturnWithVal(_, _, _) => false,
Self::TryCatch(x) => x.0.is_pure() && x.2.is_pure(),
#[cfg(not(feature = "no_module"))]
Self::Import(_, _, _) => false,
#[cfg(not(feature = "no_module"))]
Self::Export(_, _) => false,
#[cfg(not(feature = "no_closure"))]
Self::Share(_) => false,
}
}
}
/// _[INTERNALS]_ A type wrapping a custom syntax definition.
/// Exported under the `internals` feature only.
///
/// ## WARNING
///
/// This type is volatile and may change.
#[derive(Clone)]
pub struct CustomExpr {
pub(crate) keywords: StaticVec<Expr>,
pub(crate) func: Shared<FnCustomSyntaxEval>,
}
impl fmt::Debug for CustomExpr {
#[inline(always)]
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt::Debug::fmt(&self.keywords, f)
}
}
impl Hash for CustomExpr {
#[inline(always)]
fn hash<H: Hasher>(&self, state: &mut H) {
self.keywords.hash(state);
}
}
impl CustomExpr {
/// Get the keywords for this `CustomExpr`.
#[inline(always)]
pub fn keywords(&self) -> &[Expr] {
&self.keywords
}
/// Get the implementation function for this `CustomExpr`.
#[inline(always)]
pub fn func(&self) -> &FnCustomSyntaxEval {
self.func.as_ref()
}
}
/// _[INTERNALS]_ A type wrapping a floating-point number.
/// Exported under the `internals` feature only.
///
/// This type is mainly used to provide a standard `Hash` implementation
/// to floating-point numbers, allowing `Expr` to derive `Hash` automatically.
///
/// ## WARNING
///
/// This type is volatile and may change.
#[cfg(not(feature = "no_float"))]
#[derive(Debug, PartialEq, PartialOrd, Clone)]
pub struct FloatWrapper(pub FLOAT);
#[cfg(not(feature = "no_float"))]
impl Hash for FloatWrapper {
#[inline(always)]
fn hash<H: Hasher>(&self, state: &mut H) {
state.write(&self.0.to_le_bytes());
}
}
#[cfg(not(feature = "no_float"))]
impl Neg for FloatWrapper {
type Output = Self;
fn neg(self) -> Self::Output {
Self(-self.0)
}
}
#[cfg(not(feature = "no_float"))]
impl From<INT> for FloatWrapper {
fn from(value: INT) -> Self {
Self(value as FLOAT)
}
}
/// A binary expression structure.
#[derive(Debug, Clone, Hash)]
pub struct BinaryExpr {
/// LHS expression.
pub lhs: Expr,
/// RHS expression.
pub rhs: Expr,
}
/// A function call.
#[derive(Debug, Clone, Hash, Default)]
pub struct FnCallInfo {
/// Pre-calculated hash for a script-defined function of the same name and number of parameters.
pub hash: u64,
/// Call native functions only? Set to `true` to skip searching for script-defined function overrides
/// when it is certain that the function must be native (e.g. an operator).
pub native_only: bool,
/// Does this function call capture the parent scope?
pub capture: bool,
/// Default value when the function is not found, mostly used to provide a default for comparison functions.
/// Type is `bool` in order for `FnCallInfo` to be `Hash`
pub def_value: Option<bool>,
/// Namespace of the function, if any.
pub namespace: Option<Box<ModuleRef>>,
/// Function name.
/// Use `Cow<'static, str>` because a lot of operators (e.g. `==`, `>=`) are implemented as function calls
/// and the function names are predictable, so no need to allocate a new `String`.
pub name: Cow<'static, str>,
/// List of function call arguments.
pub args: StaticVec<Expr>,
}
/// _[INTERNALS]_ An expression sub-tree.
/// Exported under the `internals` feature only.
///
/// Each variant is at most one pointer in size (for speed),
/// with everything being allocated together in one single tuple.
///
/// ## WARNING
///
/// This type is volatile and may change.
#[derive(Debug, Clone, Hash)]
pub enum Expr {
/// Integer constant.
IntegerConstant(INT, Position),
/// Floating-point constant.
#[cfg(not(feature = "no_float"))]
FloatConstant(FloatWrapper, Position),
/// Character constant.
CharConstant(char, Position),
/// String constant.
StringConstant(Box<IdentX>),
/// FnPtr constant.
FnPointer(Box<IdentX>),
/// Variable access - (optional index, optional modules, hash, variable name)
Variable(Box<(Option<NonZeroUsize>, Option<Box<ModuleRef>>, u64, Ident)>),
/// Property access - (getter, setter), prop
Property(Box<((String, String), IdentX)>),
/// { stmt }
Stmt(Box<Stmt>, Position),
/// Wrapped expression - should not be optimized away.
Expr(Box<Expr>),
/// func(expr, ... )
FnCall(Box<FnCallInfo>, Position),
/// lhs.rhs
Dot(Box<BinaryExpr>, Position),
/// expr[expr]
Index(Box<BinaryExpr>, Position),
/// [ expr, ... ]
Array(Box<StaticVec<Expr>>, Position),
/// #{ name:expr, ... }
Map(Box<StaticVec<(IdentX, Expr)>>, Position),
/// lhs in rhs
In(Box<BinaryExpr>, Position),
/// lhs && rhs
And(Box<BinaryExpr>, Position),
/// lhs || rhs
Or(Box<BinaryExpr>, Position),
/// true
True(Position),
/// false
False(Position),
/// ()
Unit(Position),
/// Custom syntax
Custom(Box<CustomExpr>, Position),
}
impl Default for Expr {
#[inline(always)]
fn default() -> Self {
Self::Unit(Default::default())
}
}
impl Expr {
/// Get the type of an expression.
///
/// Returns `None` if the expression's result type is not constant.
pub fn get_type_id(&self) -> Option<TypeId> {
Some(match self {
Self::Expr(x) => return x.get_type_id(),
Self::IntegerConstant(_, _) => TypeId::of::<INT>(),
#[cfg(not(feature = "no_float"))]
Self::FloatConstant(_, _) => TypeId::of::<FLOAT>(),
Self::CharConstant(_, _) => TypeId::of::<char>(),
Self::StringConstant(_) => TypeId::of::<ImmutableString>(),
Self::FnPointer(_) => TypeId::of::<FnPtr>(),
Self::True(_) | Self::False(_) | Self::In(_, _) | Self::And(_, _) | Self::Or(_, _) => {
TypeId::of::<bool>()
}
Self::Unit(_) => TypeId::of::<()>(),
#[cfg(not(feature = "no_index"))]
Self::Array(_, _) => TypeId::of::<Array>(),
#[cfg(not(feature = "no_object"))]
Self::Map(_, _) => TypeId::of::<Map>(),
_ => return None,
})
}
/// Get the `Dynamic` value of a constant expression.
///
/// Returns `None` if the expression is not constant.
pub fn get_constant_value(&self) -> Option<Dynamic> {
Some(match self {
Self::Expr(x) => return x.get_constant_value(),
Self::IntegerConstant(x, _) => (*x).into(),
#[cfg(not(feature = "no_float"))]
Self::FloatConstant(x, _) => x.0.into(),
Self::CharConstant(x, _) => (*x).into(),
Self::StringConstant(x) => x.name.clone().into(),
Self::FnPointer(x) => Dynamic(Union::FnPtr(Box::new(FnPtr::new_unchecked(
x.name.clone(),
Default::default(),
)))),
Self::True(_) => true.into(),
Self::False(_) => false.into(),
Self::Unit(_) => ().into(),
#[cfg(not(feature = "no_index"))]
Self::Array(x, _) if x.iter().all(Self::is_constant) => Dynamic(Union::Array(
Box::new(x.iter().map(|v| v.get_constant_value().unwrap()).collect()),
)),
#[cfg(not(feature = "no_object"))]
Self::Map(x, _) if x.iter().all(|(_, v)| v.is_constant()) => {
Dynamic(Union::Map(Box::new(
x.iter()
.map(|(k, v)| (k.name.clone(), v.get_constant_value().unwrap()))
.collect(),
)))
}
_ => return None,
})
}
/// Is the expression a simple variable access?
pub(crate) fn get_variable_access(&self, non_qualified: bool) -> Option<&str> {
match self {
Self::Variable(x) if !non_qualified || x.1.is_none() => Some((x.3).name.as_str()),
_ => None,
}
}
/// Get the `Position` of the expression.
pub fn position(&self) -> Position {
match self {
Self::Expr(x) => x.position(),
#[cfg(not(feature = "no_float"))]
Self::FloatConstant(_, pos) => *pos,
Self::IntegerConstant(_, pos) => *pos,
Self::CharConstant(_, pos) => *pos,
Self::StringConstant(x) => x.pos,
Self::FnPointer(x) => x.pos,
Self::Array(_, pos) => *pos,
Self::Map(_, pos) => *pos,
Self::Property(x) => (x.1).pos,
Self::Stmt(_, pos) => *pos,
Self::Variable(x) => (x.3).pos,
Self::FnCall(_, pos) => *pos,
Self::And(x, _) | Self::Or(x, _) | Self::In(x, _) => x.lhs.position(),
Self::True(pos) | Self::False(pos) | Self::Unit(pos) => *pos,
Self::Dot(x, _) | Self::Index(x, _) => x.lhs.position(),
Self::Custom(_, pos) => *pos,
}
}
/// Override the `Position` of the expression.
pub fn set_position(&mut self, new_pos: Position) -> &mut Self {
match self {
Self::Expr(x) => {
x.set_position(new_pos);
}
#[cfg(not(feature = "no_float"))]
Self::FloatConstant(_, pos) => *pos = new_pos,
Self::IntegerConstant(_, pos) => *pos = new_pos,
Self::CharConstant(_, pos) => *pos = new_pos,
Self::StringConstant(x) => x.pos = new_pos,
Self::FnPointer(x) => x.pos = new_pos,
Self::Array(_, pos) => *pos = new_pos,
Self::Map(_, pos) => *pos = new_pos,
Self::Variable(x) => (x.3).pos = new_pos,
Self::Property(x) => (x.1).pos = new_pos,
Self::Stmt(_, pos) => *pos = new_pos,
Self::FnCall(_, pos) => *pos = new_pos,
Self::And(_, pos) | Self::Or(_, pos) | Self::In(_, pos) => *pos = new_pos,
Self::True(pos) | Self::False(pos) | Self::Unit(pos) => *pos = new_pos,
Self::Dot(_, pos) | Self::Index(_, pos) => *pos = new_pos,
Self::Custom(_, pos) => *pos = new_pos,
}
self
}
/// Is the expression pure?
///
/// A pure expression has no side effects.
pub fn is_pure(&self) -> bool {
match self {
Self::Expr(x) => x.is_pure(),
Self::Array(x, _) => x.iter().all(Self::is_pure),
Self::Map(x, _) => x.iter().map(|(_, v)| v).all(Self::is_pure),
Self::Index(x, _) | Self::And(x, _) | Self::Or(x, _) | Self::In(x, _) => {
x.lhs.is_pure() && x.rhs.is_pure()
}
Self::Stmt(x, _) => x.is_pure(),
Self::Variable(_) => true,
_ => self.is_constant(),
}
}
/// Is the expression the unit `()` literal?
#[inline(always)]
pub fn is_unit(&self) -> bool {
match self {
Self::Unit(_) => true,
_ => false,
}
}
/// Is the expression a simple constant literal?
pub fn is_literal(&self) -> bool {
match self {
Self::Expr(x) => x.is_literal(),
#[cfg(not(feature = "no_float"))]
Self::FloatConstant(_, _) => true,
Self::IntegerConstant(_, _)
| Self::CharConstant(_, _)
| Self::StringConstant(_)
| Self::FnPointer(_)
| Self::True(_)
| Self::False(_)
| Self::Unit(_) => true,
// An array literal is literal if all items are literals
Self::Array(x, _) => x.iter().all(Self::is_literal),
// An map literal is literal if all items are literals
Self::Map(x, _) => x.iter().map(|(_, expr)| expr).all(Self::is_literal),
// Check in expression
Self::In(x, _) => match (&x.lhs, &x.rhs) {
(Self::StringConstant(_), Self::StringConstant(_))
| (Self::CharConstant(_, _), Self::StringConstant(_)) => true,
_ => false,
},
_ => false,
}
}
/// Is the expression a constant?
pub fn is_constant(&self) -> bool {
match self {
Self::Expr(x) => x.is_constant(),
#[cfg(not(feature = "no_float"))]
Self::FloatConstant(_, _) => true,
Self::IntegerConstant(_, _)
| Self::CharConstant(_, _)
| Self::StringConstant(_)
| Self::FnPointer(_)
| Self::True(_)
| Self::False(_)
| Self::Unit(_) => true,
// An array literal is constant if all items are constant
Self::Array(x, _) => x.iter().all(Self::is_constant),
// An map literal is constant if all items are constant
Self::Map(x, _) => x.iter().map(|(_, expr)| expr).all(Self::is_constant),
// Check in expression
Self::In(x, _) => match (&x.lhs, &x.rhs) {
(Self::StringConstant(_), Self::StringConstant(_))
| (Self::CharConstant(_, _), Self::StringConstant(_)) => true,
_ => false,
},
_ => false,
}
}
/// Is a particular token allowed as a postfix operator to this expression?
pub fn is_valid_postfix(&self, token: &Token) -> bool {
match self {
Self::Expr(x) => x.is_valid_postfix(token),
#[cfg(not(feature = "no_float"))]
Self::FloatConstant(_, _) => false,
Self::IntegerConstant(_, _)
| Self::CharConstant(_, _)
| Self::FnPointer(_)
| Self::In(_, _)
| Self::And(_, _)
| Self::Or(_, _)
| Self::True(_)
| Self::False(_)
| Self::Unit(_) => false,
Self::StringConstant(_)
| Self::Stmt(_, _)
| Self::FnCall(_, _)
| Self::Dot(_, _)
| Self::Index(_, _)
| Self::Array(_, _)
| Self::Map(_, _) => match token {
#[cfg(not(feature = "no_index"))]
Token::LeftBracket => true,
_ => false,
},
Self::Variable(_) => match token {
#[cfg(not(feature = "no_index"))]
Token::LeftBracket => true,
Token::LeftParen => true,
Token::Bang => true,
Token::DoubleColon => true,
_ => false,
},
Self::Property(_) => match token {
#[cfg(not(feature = "no_index"))]
Token::LeftBracket => true,
Token::LeftParen => true,
_ => false,
},
Self::Custom(_, _) => false,
}
}
/// Convert a `Variable` into a `Property`. All other variants are untouched.
#[cfg(not(feature = "no_object"))]
#[inline]
pub(crate) fn into_property(self) -> Self {
match self {
Self::Variable(x) if x.1.is_none() => {
let ident = x.3;
let getter = make_getter(&ident.name);
let setter = make_setter(&ident.name);
Self::Property(Box::new(((getter, setter), ident.into())))
}
_ => self,
}
}
}
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