1886 lines
63 KiB
Rust
1886 lines
63 KiB
Rust
//! Main module defining the lexer and parser.
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use crate::any::{Dynamic, Union};
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use crate::engine::{calc_fn_def, Engine, FunctionsLib};
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use crate::error::{LexError, ParseError, ParseErrorType};
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use crate::optimize::{optimize_into_ast, OptimizationLevel};
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use crate::scope::{EntryType as ScopeEntryType, Scope};
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use crate::token::{Position, Token, TokenIterator};
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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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collections::HashMap,
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fmt::Display,
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format,
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iter::Peekable,
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ops::Add,
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rc::Rc,
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string::{String, ToString},
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sync::Arc,
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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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///
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/// Not available under the `no_float` feature.
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pub type FLOAT = f64;
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type PERR = ParseErrorType;
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/// Compiled AST (abstract syntax tree) of a Rhai script.
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///
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/// Currently, `AST` is neither `Send` nor `Sync`. Turn on the `sync` feature to make it `Send + Sync`.
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#[derive(Debug, Clone)]
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pub struct AST(
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pub(crate) Vec<Stmt>,
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#[cfg(feature = "sync")] pub(crate) Arc<FunctionsLib>,
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#[cfg(not(feature = "sync"))] pub(crate) Rc<FunctionsLib>,
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);
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impl AST {
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/// Create a new `AST`.
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pub fn new() -> Self {
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Default::default()
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}
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/// Merge two `AST` into one. Both `AST`'s are untouched and a new, merged, version
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/// is returned.
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///
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/// The second `AST` is simply appended to the end of the first _without any processing_.
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/// Thus, the return value of the first `AST` (if using expression-statement syntax) is buried.
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/// Of course, if the first `AST` uses a `return` statement at the end, then
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/// the second `AST` will essentially be dead code.
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///
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/// All script-defined functions in the second `AST` overwrite similarly-named functions
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/// in the first `AST` with the same number of parameters.
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///
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/// # Example
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///
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/// ```
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/// # fn main() -> Result<(), Box<rhai::EvalAltResult>> {
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/// # #[cfg(not(feature = "no_function"))]
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/// # {
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/// use rhai::Engine;
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///
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/// let engine = Engine::new();
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///
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/// let ast1 = engine.compile(r#"fn foo(x) { 42 + x } foo(1)"#)?;
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/// let ast2 = engine.compile(r#"fn foo(n) { "hello" + n } foo("!")"#)?;
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///
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/// let ast = ast1.merge(&ast2); // Merge 'ast2' into 'ast1'
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///
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/// // Notice that using the '+' operator also works:
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/// // let ast = &ast1 + &ast2;
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///
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/// // 'ast' is essentially:
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/// //
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/// // fn foo(n) { "hello" + n } // <- definition of first 'foo' is overwritten
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/// // foo(1) // <- notice this will be "hello1" instead of 43,
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/// // // but it is no longer the return value
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/// // foo("!") // returns "hello!"
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///
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/// // Evaluate it
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/// assert_eq!(engine.eval_ast::<String>(&ast)?, "hello!");
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/// # }
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/// # Ok(())
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/// # }
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/// ```
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pub fn merge(&self, other: &Self) -> Self {
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let Self(statements, functions) = self;
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let ast = match (statements.is_empty(), other.0.is_empty()) {
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(false, false) => {
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let mut statements = statements.clone();
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statements.extend(other.0.iter().cloned());
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statements
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}
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(false, true) => statements.clone(),
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(true, false) => other.0.clone(),
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(true, true) => vec![],
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};
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#[cfg(feature = "sync")]
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{
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Self(ast, Arc::new(functions.merge(other.1.as_ref())))
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}
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#[cfg(not(feature = "sync"))]
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{
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Self(ast, Rc::new(functions.merge(other.1.as_ref())))
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}
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}
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/// Clear all function definitions in the `AST`.
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pub fn clear_functions(&mut self) {
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#[cfg(feature = "sync")]
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{
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self.1 = Arc::new(FunctionsLib::new());
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}
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#[cfg(not(feature = "sync"))]
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{
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self.1 = Rc::new(FunctionsLib::new());
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}
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}
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/// Clear all statements in the `AST`, leaving only function definitions.
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pub fn retain_functions(&mut self) {
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self.0 = vec![];
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}
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}
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impl Default for AST {
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fn default() -> Self {
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#[cfg(feature = "sync")]
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{
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Self(vec![], Arc::new(FunctionsLib::new()))
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}
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#[cfg(not(feature = "sync"))]
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{
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Self(vec![], Rc::new(FunctionsLib::new()))
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}
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}
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}
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impl Add<Self> for &AST {
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type Output = AST;
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fn add(self, rhs: Self) -> Self::Output {
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self.merge(rhs)
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}
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}
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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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/// `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(Cow<'static, str>, Box<Expr>, Box<Stmt>),
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/// let id = expr
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Let(Cow<'static, str>, Option<Box<Expr>>, Position),
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/// const id = expr
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Const(Cow<'static, str>, 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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/// continue
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Continue(Position),
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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::Continue(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::Continue(_)
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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::Continue(_) | 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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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(Cow<'static, str>, Position),
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/// Variable access.
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Variable(Cow<'static, str>, Position),
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/// Property access.
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Property(Cow<'static, str>, 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(Cow<'static, str>, 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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Index(Box<Expr>, Box<Expr>, Position),
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/// [ expr, ... ]
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Array(Vec<Expr>, Position),
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/// #{ name:expr, ... }
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Map(Vec<(String, Expr, Position)>, Position),
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/// lhs in rhs
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In(Box<Expr>, Box<Expr>, Position),
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/// lhs && rhs
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And(Box<Expr>, Box<Expr>, Position),
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/// lhs || rhs
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Or(Box<Expr>, Box<Expr>, Position),
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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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Self::IntegerConstant(i, _) => (*i).into(),
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#[cfg(not(feature = "no_float"))]
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Self::FloatConstant(f, _) => (*f).into(),
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Self::CharConstant(c, _) => (*c).into(),
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Self::StringConstant(s, _) => s.to_string().into(),
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Self::True(_) => true.into(),
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Self::False(_) => false.into(),
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Self::Unit(_) => ().into(),
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Self::Array(items, _) if items.iter().all(Self::is_constant) => {
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Dynamic(Union::Array(Box::new(
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items
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.iter()
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.map(Self::get_constant_value)
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.collect::<Vec<_>>(),
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)))
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}
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Self::Map(items, _) if items.iter().all(|(_, v, _)| v.is_constant()) => {
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Dynamic(Union::Map(Box::new(
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items
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.iter()
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.map(|(k, v, _)| (k.clone(), v.get_constant_value()))
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.collect::<HashMap<_, _>>(),
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)))
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}
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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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Self::IntegerConstant(i, _) => i.to_string(),
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Self::FloatConstant(f, _) => f.to_string(),
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Self::CharConstant(c, _) => c.to_string(),
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Self::StringConstant(_, _) => "string".to_string(),
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Self::True(_) => "true".to_string(),
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Self::False(_) => "false".to_string(),
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Self::Unit(_) => "()".to_string(),
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Self::Array(items, _) if items.iter().all(Self::is_constant) => "array".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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Self::IntegerConstant(_, pos)
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| Self::FloatConstant(_, pos)
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| Self::CharConstant(_, pos)
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| Self::StringConstant(_, pos)
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| Self::Array(_, pos)
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| Self::Map(_, pos)
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| Self::Variable(_, pos)
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| Self::Property(_, pos)
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| Self::Stmt(_, pos)
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| Self::FunctionCall(_, _, _, pos)
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| Self::And(_, _, pos)
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| Self::Or(_, _, pos)
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| Self::In(_, _, pos)
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| Self::True(pos)
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| Self::False(pos)
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| Self::Unit(pos) => *pos,
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Self::Assignment(expr, _, _) | Self::Dot(expr, _, _) | Self::Index(expr, _, _) => {
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expr.position()
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}
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}
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}
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/// Get the `Position` of the expression.
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pub(crate) fn set_position(mut self, new_pos: Position) -> Self {
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match &mut self {
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Self::IntegerConstant(_, pos)
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| Self::FloatConstant(_, pos)
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| Self::CharConstant(_, pos)
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| Self::StringConstant(_, pos)
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| Self::Array(_, pos)
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| Self::Map(_, pos)
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| Self::Variable(_, pos)
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| Self::Property(_, pos)
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| Self::Stmt(_, pos)
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| Self::FunctionCall(_, _, _, pos)
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| Self::And(_, _, pos)
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| Self::Or(_, _, pos)
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| Self::In(_, _, pos)
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| Self::True(pos)
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| Self::False(pos)
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| Self::Unit(pos)
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| Self::Assignment(_, _, pos)
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| Self::Dot(_, _, pos)
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| Self::Index(_, _, pos) => *pos = new_pos,
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}
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self
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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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Self::Array(expressions, _) => expressions.iter().all(Self::is_pure),
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Self::Index(x, y, _) | Self::And(x, y, _) | Self::Or(x, y, _) | Self::In(x, y, _) => {
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x.is_pure() && y.is_pure()
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}
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Self::Stmt(stmt, _) => stmt.is_pure(),
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Self::Variable(_, _) => true,
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expr => expr.is_constant(),
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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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Self::IntegerConstant(_, _)
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| Self::FloatConstant(_, _)
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| Self::CharConstant(_, _)
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| Self::StringConstant(_, _)
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| Self::True(_)
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| Self::False(_)
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| Self::Unit(_) => true,
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|
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// An array literal is constant if all items are constant
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Self::Array(expressions, _) => expressions.iter().all(Self::is_constant),
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|
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// An map literal is constant if all items are constant
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Self::Map(items, _) => items.iter().map(|(_, expr, _)| expr).all(Self::is_constant),
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|
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// Check in expression
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Self::In(lhs, rhs, _) => match (lhs.as_ref(), rhs.as_ref()) {
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(Self::StringConstant(_, _), Self::StringConstant(_, _))
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| (Self::CharConstant(_, _), Self::StringConstant(_, _)) => true,
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_ => false,
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},
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_ => false,
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}
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}
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|
|
/// Is a particular token allowed as a postfix operator to this expression?
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|
pub fn is_valid_postfix(&self, token: &Token) -> bool {
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match self {
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Self::IntegerConstant(_, _)
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| Self::FloatConstant(_, _)
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| Self::CharConstant(_, _)
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| Self::In(_, _, _)
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| Self::And(_, _, _)
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| Self::Or(_, _, _)
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| Self::True(_)
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| Self::False(_)
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| Self::Unit(_) => false,
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Self::StringConstant(_, _)
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| Self::Stmt(_, _)
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| Self::FunctionCall(_, _, _, _)
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| Self::Assignment(_, _, _)
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| Self::Dot(_, _, _)
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| Self::Index(_, _, _)
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| Self::Array(_, _)
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| Self::Map(_, _) => match token {
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Token::LeftBracket => true,
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_ => false,
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},
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Self::Variable(_, _) | Self::Property(_, _) => match token {
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Token::LeftBracket | Token::LeftParen => true,
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_ => false,
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},
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}
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}
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|
|
/// Convert a `Variable` into a `Property`. All other variants are untouched.
|
|
pub(crate) fn into_property(self) -> Self {
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|
match self {
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Self::Variable(id, pos) => Self::Property(id, pos),
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_ => self,
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}
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}
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}
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|
|
/// Consume a particular token, checking that it is the expected one.
|
|
fn eat_token(input: &mut Peekable<TokenIterator>, token: Token) -> Position {
|
|
let (t, pos) = input.next().unwrap();
|
|
|
|
if t != token {
|
|
panic!(
|
|
"expecting {} (found {}) at {}",
|
|
token.syntax(),
|
|
t.syntax(),
|
|
pos
|
|
);
|
|
}
|
|
pos
|
|
}
|
|
|
|
/// Match a particular token, consuming it if matched.
|
|
fn match_token(input: &mut Peekable<TokenIterator>, token: Token) -> Result<bool, Box<ParseError>> {
|
|
let (t, _) = input.peek().unwrap();
|
|
if *t == token {
|
|
eat_token(input, token);
|
|
Ok(true)
|
|
} else {
|
|
Ok(false)
|
|
}
|
|
}
|
|
|
|
/// Parse ( expr )
|
|
fn parse_paren_expr<'a>(
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
begin: Position,
|
|
allow_stmt_expr: bool,
|
|
) -> Result<Expr, Box<ParseError>> {
|
|
if match_token(input, Token::RightParen)? {
|
|
return Ok(Expr::Unit(begin));
|
|
}
|
|
|
|
let expr = parse_expr(input, allow_stmt_expr)?;
|
|
|
|
match input.next().unwrap() {
|
|
// ( xxx )
|
|
(Token::RightParen, _) => Ok(expr),
|
|
// ( <error>
|
|
(Token::LexError(err), pos) => return Err(PERR::BadInput(err.to_string()).into_err(pos)),
|
|
// ( xxx ???
|
|
(_, pos) => Err(PERR::MissingToken(
|
|
")".into(),
|
|
"for a matching ( in this expression".into(),
|
|
)
|
|
.into_err(pos)),
|
|
}
|
|
}
|
|
|
|
/// Parse a function call.
|
|
fn parse_call_expr<'a, S: Into<Cow<'static, str>> + Display>(
|
|
id: S,
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
begin: Position,
|
|
allow_stmt_expr: bool,
|
|
) -> Result<Expr, Box<ParseError>> {
|
|
let mut args_expr_list = Vec::new();
|
|
|
|
match input.peek().unwrap() {
|
|
// id <EOF>
|
|
(Token::EOF, pos) => {
|
|
return Err(PERR::MissingToken(
|
|
")".into(),
|
|
format!("to close the arguments list of this function call '{}'", id),
|
|
)
|
|
.into_err(*pos))
|
|
}
|
|
// id <error>
|
|
(Token::LexError(err), pos) => return Err(PERR::BadInput(err.to_string()).into_err(*pos)),
|
|
// id()
|
|
(Token::RightParen, _) => {
|
|
eat_token(input, Token::RightParen);
|
|
return Ok(Expr::FunctionCall(id.into(), args_expr_list, None, begin));
|
|
}
|
|
// id...
|
|
_ => (),
|
|
}
|
|
|
|
loop {
|
|
args_expr_list.push(parse_expr(input, allow_stmt_expr)?);
|
|
|
|
match input.peek().unwrap() {
|
|
(Token::RightParen, _) => {
|
|
eat_token(input, Token::RightParen);
|
|
return Ok(Expr::FunctionCall(id.into(), args_expr_list, None, begin));
|
|
}
|
|
(Token::Comma, _) => {
|
|
eat_token(input, Token::Comma);
|
|
}
|
|
(Token::EOF, pos) => {
|
|
return Err(PERR::MissingToken(
|
|
")".into(),
|
|
format!("to close the arguments list of this function call '{}'", id),
|
|
)
|
|
.into_err(*pos))
|
|
}
|
|
(Token::LexError(err), pos) => {
|
|
return Err(PERR::BadInput(err.to_string()).into_err(*pos))
|
|
}
|
|
(_, pos) => {
|
|
return Err(PERR::MissingToken(
|
|
",".into(),
|
|
format!("to separate the arguments to function call '{}'", id),
|
|
)
|
|
.into_err(*pos))
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Parse an indexing chain.
|
|
/// Indexing binds to the right, so this call parses all possible levels of indexing following in the input.
|
|
fn parse_index_chain<'a>(
|
|
lhs: Expr,
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
pos: Position,
|
|
allow_stmt_expr: bool,
|
|
) -> Result<Expr, Box<ParseError>> {
|
|
let idx_expr = parse_expr(input, allow_stmt_expr)?;
|
|
|
|
// Check type of indexing - must be integer or string
|
|
match &idx_expr {
|
|
// lhs[int]
|
|
Expr::IntegerConstant(i, pos) if *i < 0 => {
|
|
return Err(PERR::MalformedIndexExpr(format!(
|
|
"Array access expects non-negative index: {} < 0",
|
|
i
|
|
))
|
|
.into_err(*pos))
|
|
}
|
|
Expr::IntegerConstant(_, pos) => match lhs {
|
|
Expr::Array(_, _) | Expr::StringConstant(_, _) => (),
|
|
|
|
Expr::Map(_, _) => {
|
|
return Err(PERR::MalformedIndexExpr(
|
|
"Object map access expects string index, not a number".into(),
|
|
)
|
|
.into_err(*pos))
|
|
}
|
|
|
|
Expr::FloatConstant(_, pos)
|
|
| Expr::CharConstant(_, pos)
|
|
| Expr::Assignment(_, _, pos)
|
|
| Expr::And(_, _, pos)
|
|
| Expr::Or(_, _, pos)
|
|
| Expr::In(_, _, pos)
|
|
| Expr::True(pos)
|
|
| Expr::False(pos)
|
|
| Expr::Unit(pos) => {
|
|
return Err(PERR::MalformedIndexExpr(
|
|
"Only arrays, object maps and strings can be indexed".into(),
|
|
)
|
|
.into_err(pos))
|
|
}
|
|
|
|
_ => (),
|
|
},
|
|
|
|
// lhs[string]
|
|
Expr::StringConstant(_, pos) => match lhs {
|
|
Expr::Map(_, _) => (),
|
|
|
|
Expr::Array(_, _) | Expr::StringConstant(_, _) => {
|
|
return Err(PERR::MalformedIndexExpr(
|
|
"Array or string expects numeric index, not a string".into(),
|
|
)
|
|
.into_err(*pos))
|
|
}
|
|
Expr::FloatConstant(_, pos)
|
|
| Expr::CharConstant(_, pos)
|
|
| Expr::Assignment(_, _, pos)
|
|
| Expr::And(_, _, pos)
|
|
| Expr::Or(_, _, pos)
|
|
| Expr::In(_, _, pos)
|
|
| Expr::True(pos)
|
|
| Expr::False(pos)
|
|
| Expr::Unit(pos) => {
|
|
return Err(PERR::MalformedIndexExpr(
|
|
"Only arrays, object maps and strings can be indexed".into(),
|
|
)
|
|
.into_err(pos))
|
|
}
|
|
|
|
_ => (),
|
|
},
|
|
|
|
// lhs[float]
|
|
Expr::FloatConstant(_, pos) => {
|
|
return Err(PERR::MalformedIndexExpr(
|
|
"Array access expects integer index, not a float".into(),
|
|
)
|
|
.into_err(*pos))
|
|
}
|
|
// lhs[char]
|
|
Expr::CharConstant(_, pos) => {
|
|
return Err(PERR::MalformedIndexExpr(
|
|
"Array access expects integer index, not a character".into(),
|
|
)
|
|
.into_err(*pos))
|
|
}
|
|
// lhs[??? = ??? ], lhs[()]
|
|
Expr::Assignment(_, _, pos) | Expr::Unit(pos) => {
|
|
return Err(PERR::MalformedIndexExpr(
|
|
"Array access expects integer index, not ()".into(),
|
|
)
|
|
.into_err(*pos))
|
|
}
|
|
// lhs[??? && ???], lhs[??? || ???], lhs[??? in ???], lhs[true], lhs[false]
|
|
Expr::And(_, _, pos)
|
|
| Expr::Or(_, _, pos)
|
|
| Expr::In(_, _, pos)
|
|
| Expr::True(pos)
|
|
| Expr::False(pos) => {
|
|
return Err(PERR::MalformedIndexExpr(
|
|
"Array access expects integer index, not a boolean".into(),
|
|
)
|
|
.into_err(*pos))
|
|
}
|
|
// All other expressions
|
|
_ => (),
|
|
}
|
|
|
|
// Check if there is a closing bracket
|
|
match input.peek().unwrap() {
|
|
(Token::RightBracket, _) => {
|
|
eat_token(input, Token::RightBracket);
|
|
|
|
// Any more indexing following?
|
|
match input.peek().unwrap() {
|
|
// If another indexing level, right-bind it
|
|
(Token::LeftBracket, _) => {
|
|
let follow_pos = eat_token(input, Token::LeftBracket);
|
|
// Recursively parse the indexing chain, right-binding each
|
|
let follow = parse_index_chain(idx_expr, input, follow_pos, allow_stmt_expr)?;
|
|
// Indexing binds to right
|
|
Ok(Expr::Index(Box::new(lhs), Box::new(follow), pos))
|
|
}
|
|
// Otherwise terminate the indexing chain
|
|
_ => Ok(Expr::Index(Box::new(lhs), Box::new(idx_expr), pos)),
|
|
}
|
|
}
|
|
(Token::LexError(err), pos) => return Err(PERR::BadInput(err.to_string()).into_err(*pos)),
|
|
(_, pos) => Err(PERR::MissingToken(
|
|
"]".into(),
|
|
"for a matching [ in this index expression".into(),
|
|
)
|
|
.into_err(*pos)),
|
|
}
|
|
}
|
|
|
|
/// Parse an array literal.
|
|
fn parse_array_literal<'a>(
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
begin: Position,
|
|
allow_stmt_expr: bool,
|
|
) -> Result<Expr, Box<ParseError>> {
|
|
let mut arr = Vec::new();
|
|
|
|
if !match_token(input, Token::RightBracket)? {
|
|
while !input.peek().unwrap().0.is_eof() {
|
|
arr.push(parse_expr(input, allow_stmt_expr)?);
|
|
|
|
match input.peek().unwrap() {
|
|
(Token::Comma, _) => eat_token(input, Token::Comma),
|
|
(Token::RightBracket, _) => {
|
|
eat_token(input, Token::RightBracket);
|
|
break;
|
|
}
|
|
(Token::EOF, pos) => {
|
|
return Err(
|
|
PERR::MissingToken("]".into(), "to end this array literal".into())
|
|
.into_err(*pos),
|
|
)
|
|
}
|
|
(Token::LexError(err), pos) => {
|
|
return Err(PERR::BadInput(err.to_string()).into_err(*pos))
|
|
}
|
|
(_, pos) => {
|
|
return Err(PERR::MissingToken(
|
|
",".into(),
|
|
"to separate the items of this array literal".into(),
|
|
)
|
|
.into_err(*pos))
|
|
}
|
|
};
|
|
}
|
|
}
|
|
|
|
Ok(Expr::Array(arr, begin))
|
|
}
|
|
|
|
/// Parse a map literal.
|
|
fn parse_map_literal<'a>(
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
begin: Position,
|
|
allow_stmt_expr: bool,
|
|
) -> Result<Expr, Box<ParseError>> {
|
|
let mut map = Vec::new();
|
|
|
|
if !match_token(input, Token::RightBrace)? {
|
|
while !input.peek().unwrap().0.is_eof() {
|
|
const MISSING_RBRACE: &str = "to end this object map literal";
|
|
|
|
let (name, pos) = match input.next().unwrap() {
|
|
(Token::Identifier(s), pos) => (s, pos),
|
|
(Token::StringConst(s), pos) => (s, pos),
|
|
(Token::LexError(err), pos) => {
|
|
return Err(PERR::BadInput(err.to_string()).into_err(pos))
|
|
}
|
|
(_, pos) if map.is_empty() => {
|
|
return Err(PERR::MissingToken("}".into(), MISSING_RBRACE.into()).into_err(pos))
|
|
}
|
|
(Token::EOF, pos) => {
|
|
return Err(PERR::MissingToken("}".into(), MISSING_RBRACE.into()).into_err(pos))
|
|
}
|
|
(_, pos) => return Err(PERR::PropertyExpected.into_err(pos)),
|
|
};
|
|
|
|
match input.next().unwrap() {
|
|
(Token::Colon, _) => (),
|
|
(Token::LexError(err), pos) => {
|
|
return Err(PERR::BadInput(err.to_string()).into_err(pos))
|
|
}
|
|
(_, pos) => {
|
|
return Err(PERR::MissingToken(
|
|
":".into(),
|
|
format!(
|
|
"to follow the property '{}' in this object map literal",
|
|
name
|
|
),
|
|
)
|
|
.into_err(pos))
|
|
}
|
|
};
|
|
|
|
let expr = parse_expr(input, allow_stmt_expr)?;
|
|
|
|
map.push((name, expr, pos));
|
|
|
|
match input.peek().unwrap() {
|
|
(Token::Comma, _) => {
|
|
eat_token(input, Token::Comma);
|
|
}
|
|
(Token::RightBrace, _) => {
|
|
eat_token(input, Token::RightBrace);
|
|
break;
|
|
}
|
|
(Token::Identifier(_), pos) => {
|
|
return Err(PERR::MissingToken(
|
|
",".into(),
|
|
"to separate the items of this object map literal".into(),
|
|
)
|
|
.into_err(*pos))
|
|
}
|
|
(Token::LexError(err), pos) => {
|
|
return Err(PERR::BadInput(err.to_string()).into_err(*pos))
|
|
}
|
|
(_, pos) => {
|
|
return Err(PERR::MissingToken("}".into(), MISSING_RBRACE.into()).into_err(*pos))
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// Check for duplicating properties
|
|
map.iter()
|
|
.enumerate()
|
|
.try_for_each(|(i, (k1, _, _))| {
|
|
map.iter()
|
|
.skip(i + 1)
|
|
.find(|(k2, _, _)| k2 == k1)
|
|
.map_or_else(|| Ok(()), |(k2, _, pos)| Err((k2, *pos)))
|
|
})
|
|
.map_err(|(key, pos)| PERR::DuplicatedProperty(key.to_string()).into_err(pos))?;
|
|
|
|
Ok(Expr::Map(map, begin))
|
|
}
|
|
|
|
/// Parse a primary expression.
|
|
fn parse_primary<'a>(
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
allow_stmt_expr: bool,
|
|
) -> Result<Expr, Box<ParseError>> {
|
|
let (token, pos) = match input.peek().unwrap() {
|
|
// { - 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));
|
|
}
|
|
(Token::EOF, pos) => return Err(PERR::UnexpectedEOF.into_err(*pos)),
|
|
_ => input.next().unwrap(),
|
|
};
|
|
|
|
let mut root_expr = match token {
|
|
Token::IntegerConstant(x) => Expr::IntegerConstant(x, pos),
|
|
#[cfg(not(feature = "no_float"))]
|
|
Token::FloatConstant(x) => Expr::FloatConstant(x, pos),
|
|
Token::CharConstant(c) => Expr::CharConstant(c, pos),
|
|
Token::StringConst(s) => Expr::StringConstant(s.into(), pos),
|
|
Token::Identifier(s) => Expr::Variable(s.into(), pos),
|
|
Token::LeftParen => parse_paren_expr(input, pos, allow_stmt_expr)?,
|
|
#[cfg(not(feature = "no_index"))]
|
|
Token::LeftBracket => parse_array_literal(input, pos, allow_stmt_expr)?,
|
|
#[cfg(not(feature = "no_object"))]
|
|
Token::MapStart => parse_map_literal(input, pos, allow_stmt_expr)?,
|
|
Token::True => Expr::True(pos),
|
|
Token::False => Expr::False(pos),
|
|
Token::LexError(err) => return Err(PERR::BadInput(err.to_string()).into_err(pos)),
|
|
token => {
|
|
return Err(PERR::BadInput(format!("Unexpected '{}'", token.syntax())).into_err(pos))
|
|
}
|
|
};
|
|
|
|
// Tail processing all possible postfix operators
|
|
loop {
|
|
let (token, _) = input.peek().unwrap();
|
|
|
|
if !root_expr.is_valid_postfix(token) {
|
|
break;
|
|
}
|
|
|
|
let (token, pos) = input.next().unwrap();
|
|
|
|
root_expr = match (root_expr, token) {
|
|
// Function call
|
|
(Expr::Variable(id, pos), Token::LeftParen)
|
|
| (Expr::Property(id, pos), Token::LeftParen) => {
|
|
parse_call_expr(id, input, pos, allow_stmt_expr)?
|
|
}
|
|
// Indexing
|
|
(expr, Token::LeftBracket) => parse_index_chain(expr, input, pos, allow_stmt_expr)?,
|
|
// Unknown postfix operator
|
|
(expr, token) => panic!("unknown postfix operator {:?} for {:?}", token, expr),
|
|
}
|
|
}
|
|
|
|
Ok(root_expr)
|
|
}
|
|
|
|
/// Parse a potential unary operator.
|
|
fn parse_unary<'a>(
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
allow_stmt_expr: bool,
|
|
) -> Result<Expr, Box<ParseError>> {
|
|
match input.peek().unwrap() {
|
|
// If statement is allowed to act as expressions
|
|
(Token::If, pos) => {
|
|
let pos = *pos;
|
|
Ok(Expr::Stmt(
|
|
Box::new(parse_if(input, false, allow_stmt_expr)?),
|
|
pos,
|
|
))
|
|
}
|
|
// -expr
|
|
(Token::UnaryMinus, _) => {
|
|
let pos = eat_token(input, Token::UnaryMinus);
|
|
|
|
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"))]
|
|
{
|
|
Some(Expr::FloatConstant(-(i as FLOAT), pos))
|
|
}
|
|
#[cfg(feature = "no_float")]
|
|
{
|
|
None
|
|
}
|
|
})
|
|
.ok_or_else(|| {
|
|
PERR::BadInput(LexError::MalformedNumber(format!("-{}", i)).to_string())
|
|
.into_err(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, _) => {
|
|
eat_token(input, Token::UnaryPlus);
|
|
parse_unary(input, allow_stmt_expr)
|
|
}
|
|
// !expr
|
|
(Token::Bang, _) => {
|
|
let pos = eat_token(input, Token::Bang);
|
|
Ok(Expr::FunctionCall(
|
|
"!".into(),
|
|
vec![parse_primary(input, allow_stmt_expr)?],
|
|
Some(false.into()), // NOT operator, when operating on invalid operand, defaults to false
|
|
pos,
|
|
))
|
|
}
|
|
// <EOF>
|
|
(Token::EOF, pos) => Err(PERR::UnexpectedEOF.into_err(*pos)),
|
|
// All other tokens
|
|
_ => parse_primary(input, allow_stmt_expr),
|
|
}
|
|
}
|
|
|
|
fn parse_assignment_stmt<'a>(
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
lhs: Expr,
|
|
allow_stmt_expr: bool,
|
|
) -> Result<Expr, Box<ParseError>> {
|
|
let pos = eat_token(input, Token::Equals);
|
|
let rhs = parse_expr(input, allow_stmt_expr)?;
|
|
Ok(Expr::Assignment(Box::new(lhs), Box::new(rhs), pos))
|
|
}
|
|
|
|
/// Parse an operator-assignment expression.
|
|
fn parse_op_assignment_stmt<'a>(
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
lhs: Expr,
|
|
allow_stmt_expr: bool,
|
|
) -> Result<Expr, Box<ParseError>> {
|
|
let (op, pos) = match *input.peek().unwrap() {
|
|
(Token::Equals, _) => return parse_assignment_stmt(input, lhs, allow_stmt_expr),
|
|
(Token::PlusAssign, pos) => ("+", pos),
|
|
(Token::MinusAssign, pos) => ("-", pos),
|
|
(Token::MultiplyAssign, pos) => ("*", pos),
|
|
(Token::DivideAssign, pos) => ("/", pos),
|
|
(Token::LeftShiftAssign, pos) => ("<<", pos),
|
|
(Token::RightShiftAssign, pos) => (">>", pos),
|
|
(Token::ModuloAssign, pos) => ("%", pos),
|
|
(Token::PowerOfAssign, pos) => ("~", pos),
|
|
(Token::AndAssign, pos) => ("&", pos),
|
|
(Token::OrAssign, pos) => ("|", pos),
|
|
(Token::XOrAssign, pos) => ("^", pos),
|
|
(_, _) => return Ok(lhs),
|
|
};
|
|
|
|
input.next();
|
|
|
|
let lhs_copy = lhs.clone();
|
|
let rhs = parse_expr(input, allow_stmt_expr)?;
|
|
|
|
// lhs op= rhs -> lhs = op(lhs, rhs)
|
|
let rhs_expr = Expr::FunctionCall(op.into(), vec![lhs_copy, rhs], None, pos);
|
|
Ok(Expr::Assignment(Box::new(lhs), Box::new(rhs_expr), pos))
|
|
}
|
|
|
|
/// Make a dot expression.
|
|
fn make_dot_expr(lhs: Expr, rhs: Expr, op_pos: Position, is_index: bool) -> Expr {
|
|
match (lhs, rhs) {
|
|
// idx_lhs[idx_rhs].rhs
|
|
// Attach dot chain to the bottom level of indexing chain
|
|
(Expr::Index(idx_lhs, idx_rhs, idx_pos), rhs) => Expr::Index(
|
|
idx_lhs,
|
|
Box::new(make_dot_expr(*idx_rhs, rhs, op_pos, true)),
|
|
idx_pos,
|
|
),
|
|
// lhs.id
|
|
(lhs, rhs @ Expr::Variable(_, _)) | (lhs, rhs @ Expr::Property(_, _)) => {
|
|
let lhs = if is_index { lhs.into_property() } else { lhs };
|
|
Expr::Dot(Box::new(lhs), Box::new(rhs.into_property()), op_pos)
|
|
}
|
|
// lhs.dot_lhs.dot_rhs
|
|
(lhs, Expr::Dot(dot_lhs, dot_rhs, dot_pos)) => Expr::Dot(
|
|
Box::new(lhs),
|
|
Box::new(Expr::Dot(
|
|
Box::new(dot_lhs.into_property()),
|
|
Box::new(dot_rhs.into_property()),
|
|
dot_pos,
|
|
)),
|
|
op_pos,
|
|
),
|
|
// lhs.idx_lhs[idx_rhs]
|
|
(lhs, Expr::Index(idx_lhs, idx_rhs, idx_pos)) => Expr::Dot(
|
|
Box::new(lhs),
|
|
Box::new(Expr::Index(
|
|
Box::new(idx_lhs.into_property()),
|
|
Box::new(idx_rhs.into_property()),
|
|
idx_pos,
|
|
)),
|
|
op_pos,
|
|
),
|
|
// lhs.rhs
|
|
(lhs, rhs) => Expr::Dot(Box::new(lhs), Box::new(rhs.into_property()), op_pos),
|
|
}
|
|
}
|
|
|
|
/// Make an 'in' expression.
|
|
fn make_in_expr(lhs: Expr, rhs: Expr, op_pos: Position) -> Result<Expr, Box<ParseError>> {
|
|
match (&lhs, &rhs) {
|
|
(_, Expr::IntegerConstant(_, pos))
|
|
| (_, Expr::FloatConstant(_, pos))
|
|
| (_, Expr::And(_, _, pos))
|
|
| (_, Expr::Or(_, _, pos))
|
|
| (_, Expr::In(_, _, pos))
|
|
| (_, Expr::True(pos))
|
|
| (_, Expr::False(pos))
|
|
| (_, Expr::Assignment(_, _, pos))
|
|
| (_, Expr::Unit(pos)) => {
|
|
return Err(PERR::MalformedInExpr(
|
|
"'in' expression expects a string, array or object map".into(),
|
|
)
|
|
.into_err(*pos))
|
|
}
|
|
|
|
// "xxx" in "xxxx", 'x' in "xxxx" - OK!
|
|
(Expr::StringConstant(_, _), Expr::StringConstant(_, _))
|
|
| (Expr::CharConstant(_, _), Expr::StringConstant(_, _)) => (),
|
|
|
|
// 123.456 in "xxxx"
|
|
(Expr::FloatConstant(_, pos), Expr::StringConstant(_, _)) => {
|
|
return Err(PERR::MalformedInExpr(
|
|
"'in' expression for a string expects a string, not a float".into(),
|
|
)
|
|
.into_err(*pos))
|
|
}
|
|
// 123 in "xxxx"
|
|
(Expr::IntegerConstant(_, pos), Expr::StringConstant(_, _)) => {
|
|
return Err(PERR::MalformedInExpr(
|
|
"'in' expression for a string expects a string, not a number".into(),
|
|
)
|
|
.into_err(*pos))
|
|
}
|
|
// (??? && ???) in "xxxx", (??? || ???) in "xxxx", (??? in ???) in "xxxx",
|
|
// true in "xxxx", false in "xxxx"
|
|
(Expr::And(_, _, pos), Expr::StringConstant(_, _))
|
|
| (Expr::Or(_, _, pos), Expr::StringConstant(_, _))
|
|
| (Expr::In(_, _, pos), Expr::StringConstant(_, _))
|
|
| (Expr::True(pos), Expr::StringConstant(_, _))
|
|
| (Expr::False(pos), Expr::StringConstant(_, _)) => {
|
|
return Err(PERR::MalformedInExpr(
|
|
"'in' expression for a string expects a string, not a boolean".into(),
|
|
)
|
|
.into_err(*pos))
|
|
}
|
|
// [???, ???, ???] in "xxxx"
|
|
(Expr::Array(_, pos), Expr::StringConstant(_, _)) => {
|
|
return Err(PERR::MalformedInExpr(
|
|
"'in' expression for a string expects a string, not an array".into(),
|
|
)
|
|
.into_err(*pos))
|
|
}
|
|
// #{...} in "xxxx"
|
|
(Expr::Map(_, pos), Expr::StringConstant(_, _)) => {
|
|
return Err(PERR::MalformedInExpr(
|
|
"'in' expression for a string expects a string, not an object map".into(),
|
|
)
|
|
.into_err(*pos))
|
|
}
|
|
// (??? = ???) in "xxxx", () in "xxxx"
|
|
(Expr::Assignment(_, _, pos), Expr::StringConstant(_, _))
|
|
| (Expr::Unit(pos), Expr::StringConstant(_, _)) => {
|
|
return Err(PERR::MalformedInExpr(
|
|
"'in' expression for a string expects a string, not ()".into(),
|
|
)
|
|
.into_err(*pos))
|
|
}
|
|
|
|
// "xxx" in #{...}, 'x' in #{...} - OK!
|
|
(Expr::StringConstant(_, _), Expr::Map(_, _))
|
|
| (Expr::CharConstant(_, _), Expr::Map(_, _)) => (),
|
|
|
|
// 123.456 in #{...}
|
|
(Expr::FloatConstant(_, pos), Expr::Map(_, _)) => {
|
|
return Err(PERR::MalformedInExpr(
|
|
"'in' expression for an object map expects a string, not a float".into(),
|
|
)
|
|
.into_err(*pos))
|
|
}
|
|
// 123 in #{...}
|
|
(Expr::IntegerConstant(_, pos), Expr::Map(_, _)) => {
|
|
return Err(PERR::MalformedInExpr(
|
|
"'in' expression for an object map expects a string, not a number".into(),
|
|
)
|
|
.into_err(*pos))
|
|
}
|
|
// (??? && ???) in #{...}, (??? || ???) in #{...}, (??? in ???) in #{...},
|
|
// true in #{...}, false in #{...}
|
|
(Expr::And(_, _, pos), Expr::Map(_, _))
|
|
| (Expr::Or(_, _, pos), Expr::Map(_, _))
|
|
| (Expr::In(_, _, pos), Expr::Map(_, _))
|
|
| (Expr::True(pos), Expr::Map(_, _))
|
|
| (Expr::False(pos), Expr::Map(_, _)) => {
|
|
return Err(PERR::MalformedInExpr(
|
|
"'in' expression for an object map expects a string, not a boolean".into(),
|
|
)
|
|
.into_err(*pos))
|
|
}
|
|
// [???, ???, ???] in #{..}
|
|
(Expr::Array(_, pos), Expr::Map(_, _)) => {
|
|
return Err(PERR::MalformedInExpr(
|
|
"'in' expression for an object map expects a string, not an array".into(),
|
|
)
|
|
.into_err(*pos))
|
|
}
|
|
// #{...} in #{..}
|
|
(Expr::Map(_, pos), Expr::Map(_, _)) => {
|
|
return Err(PERR::MalformedInExpr(
|
|
"'in' expression for an object map expects a string, not an object map".into(),
|
|
)
|
|
.into_err(*pos))
|
|
}
|
|
// (??? = ???) in #{...}, () in #{...}
|
|
(Expr::Assignment(_, _, pos), Expr::Map(_, _)) | (Expr::Unit(pos), Expr::Map(_, _)) => {
|
|
return Err(PERR::MalformedInExpr(
|
|
"'in' expression for an object map expects a string, not ()".into(),
|
|
)
|
|
.into_err(*pos))
|
|
}
|
|
|
|
_ => (),
|
|
}
|
|
|
|
Ok(Expr::In(Box::new(lhs), Box::new(rhs), op_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, Box<ParseError>> {
|
|
let mut current_lhs = lhs;
|
|
|
|
loop {
|
|
let (current_precedence, bind_right) = input.peek().map_or_else(
|
|
|| (0, false),
|
|
|(current_op, _)| (current_op.precedence(), current_op.is_bind_right()),
|
|
);
|
|
|
|
// Bind left to the parent lhs expression if precedence is higher
|
|
// If same precedence, then check if the operator binds right
|
|
if current_precedence < parent_precedence
|
|
|| (current_precedence == parent_precedence && !bind_right)
|
|
{
|
|
return Ok(current_lhs);
|
|
}
|
|
|
|
let (op_token, pos) = input.next().unwrap();
|
|
|
|
let rhs = parse_unary(input, allow_stmt_expr)?;
|
|
|
|
let next_precedence = input.peek().unwrap().0.precedence();
|
|
|
|
// 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::LeftShift => Expr::FunctionCall("<<".into(), vec![current_lhs, rhs], None, pos),
|
|
Token::RightShift => Expr::FunctionCall(">>".into(), vec![current_lhs, rhs], None, pos),
|
|
Token::Modulo => Expr::FunctionCall("%".into(), vec![current_lhs, rhs], None, pos),
|
|
Token::PowerOf => Expr::FunctionCall("~".into(), vec![current_lhs, rhs], None, pos),
|
|
|
|
// Comparison operators default to false when passed invalid operands
|
|
Token::EqualsTo => {
|
|
Expr::FunctionCall("==".into(), vec![current_lhs, rhs], Some(false.into()), pos)
|
|
}
|
|
Token::NotEqualsTo => {
|
|
Expr::FunctionCall("!=".into(), vec![current_lhs, rhs], Some(false.into()), pos)
|
|
}
|
|
Token::LessThan => {
|
|
Expr::FunctionCall("<".into(), vec![current_lhs, rhs], Some(false.into()), pos)
|
|
}
|
|
Token::LessThanEqualsTo => {
|
|
Expr::FunctionCall("<=".into(), vec![current_lhs, rhs], Some(false.into()), pos)
|
|
}
|
|
Token::GreaterThan => {
|
|
Expr::FunctionCall(">".into(), vec![current_lhs, rhs], Some(false.into()), pos)
|
|
}
|
|
Token::GreaterThanEqualsTo => {
|
|
Expr::FunctionCall(">=".into(), vec![current_lhs, rhs], Some(false.into()), pos)
|
|
}
|
|
|
|
Token::Or => Expr::Or(Box::new(current_lhs), Box::new(rhs), pos),
|
|
Token::And => Expr::And(Box::new(current_lhs), Box::new(rhs), pos),
|
|
Token::Ampersand => Expr::FunctionCall("&".into(), vec![current_lhs, rhs], None, pos),
|
|
Token::Pipe => Expr::FunctionCall("|".into(), vec![current_lhs, rhs], None, pos),
|
|
Token::XOr => Expr::FunctionCall("^".into(), vec![current_lhs, rhs], None, pos),
|
|
|
|
Token::In => make_in_expr(current_lhs, rhs, pos)?,
|
|
|
|
#[cfg(not(feature = "no_object"))]
|
|
Token::Period => make_dot_expr(current_lhs, rhs, pos, false),
|
|
|
|
token => return Err(PERR::UnknownOperator(token.syntax().into()).into_err(pos)),
|
|
};
|
|
}
|
|
}
|
|
|
|
/// Parse an expression.
|
|
fn parse_expr<'a>(
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
allow_stmt_expr: bool,
|
|
) -> Result<Expr, Box<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<(), Box<ParseError>> {
|
|
match input.peek().unwrap() {
|
|
// Disallow statement expressions
|
|
(Token::LeftBrace, pos) | (Token::EOF, pos) => {
|
|
Err(PERR::ExprExpected(type_name.to_string()).into_err(*pos))
|
|
}
|
|
// No need to check for others at this time - leave it for the expr parser
|
|
_ => Ok(()),
|
|
}
|
|
}
|
|
|
|
/// Make sure that the expression is not a mis-typed assignment (i.e. `a = b` instead of `a == b`).
|
|
fn ensure_not_assignment<'a>(
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
) -> Result<(), Box<ParseError>> {
|
|
match input.peek().unwrap() {
|
|
(Token::Equals, pos) => {
|
|
return Err(PERR::BadInput("Possibly a typo of '=='?".to_string()).into_err(*pos))
|
|
}
|
|
(Token::PlusAssign, pos)
|
|
| (Token::MinusAssign, pos)
|
|
| (Token::MultiplyAssign, pos)
|
|
| (Token::DivideAssign, pos)
|
|
| (Token::LeftShiftAssign, pos)
|
|
| (Token::RightShiftAssign, pos)
|
|
| (Token::ModuloAssign, pos)
|
|
| (Token::PowerOfAssign, pos)
|
|
| (Token::AndAssign, pos)
|
|
| (Token::OrAssign, pos)
|
|
| (Token::XOrAssign, pos) => {
|
|
return Err(PERR::BadInput(
|
|
"Expecting a boolean expression, not an assignment".to_string(),
|
|
)
|
|
.into_err(*pos))
|
|
}
|
|
|
|
_ => Ok(()),
|
|
}
|
|
}
|
|
|
|
/// Parse an if statement.
|
|
fn parse_if<'a>(
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
breakable: bool,
|
|
allow_stmt_expr: bool,
|
|
) -> Result<Stmt, Box<ParseError>> {
|
|
// if ...
|
|
eat_token(input, Token::If);
|
|
|
|
// if guard { if_body }
|
|
ensure_not_statement_expr(input, "a boolean")?;
|
|
let guard = parse_expr(input, allow_stmt_expr)?;
|
|
ensure_not_assignment(input)?;
|
|
let if_body = parse_block(input, breakable, allow_stmt_expr)?;
|
|
|
|
// if guard { if_body } else ...
|
|
let else_body = if match_token(input, Token::Else).unwrap_or(false) {
|
|
Some(Box::new(if let (Token::If, _) = input.peek().unwrap() {
|
|
// 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, Box<ParseError>> {
|
|
// while ...
|
|
eat_token(input, Token::While);
|
|
|
|
// while guard { body }
|
|
ensure_not_statement_expr(input, "a boolean")?;
|
|
let guard = parse_expr(input, allow_stmt_expr)?;
|
|
ensure_not_assignment(input)?;
|
|
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, Box<ParseError>> {
|
|
// loop ...
|
|
eat_token(input, Token::Loop);
|
|
|
|
// 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, Box<ParseError>> {
|
|
// for ...
|
|
eat_token(input, Token::For);
|
|
|
|
// for name ...
|
|
let name = match input.next().unwrap() {
|
|
// Variable name
|
|
(Token::Identifier(s), _) => s,
|
|
// Bad identifier
|
|
(Token::LexError(err), pos) => return Err(PERR::BadInput(err.to_string()).into_err(pos)),
|
|
// EOF
|
|
(Token::EOF, pos) => return Err(PERR::VariableExpected.into_err(pos)),
|
|
// Not a variable name
|
|
(_, pos) => return Err(PERR::VariableExpected.into_err(pos)),
|
|
};
|
|
|
|
// for name in ...
|
|
match input.next().unwrap() {
|
|
(Token::In, _) => (),
|
|
(Token::LexError(err), pos) => return Err(PERR::BadInput(err.to_string()).into_err(pos)),
|
|
(_, pos) => {
|
|
return Err(
|
|
PERR::MissingToken("in".into(), "after the iteration variable".into())
|
|
.into_err(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.into(), Box::new(expr), Box::new(body)))
|
|
}
|
|
|
|
/// Parse a variable definition statement.
|
|
fn parse_let<'a>(
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
var_type: ScopeEntryType,
|
|
allow_stmt_expr: bool,
|
|
) -> Result<Stmt, Box<ParseError>> {
|
|
// let/const... (specified in `var_type`)
|
|
input.next();
|
|
|
|
// let name ...
|
|
let (name, pos) = match input.next().unwrap() {
|
|
(Token::Identifier(s), pos) => (s, pos),
|
|
(Token::LexError(err), pos) => return Err(PERR::BadInput(err.to_string()).into_err(pos)),
|
|
(_, pos) => return Err(PERR::VariableExpected.into_err(pos)),
|
|
};
|
|
|
|
// let name = ...
|
|
if match_token(input, Token::Equals)? {
|
|
// let name = expr
|
|
let init_value = parse_expr(input, allow_stmt_expr)?;
|
|
|
|
match var_type {
|
|
// let name = expr
|
|
ScopeEntryType::Normal => Ok(Stmt::Let(name.into(), Some(Box::new(init_value)), pos)),
|
|
// const name = { expr:constant }
|
|
ScopeEntryType::Constant if init_value.is_constant() => {
|
|
Ok(Stmt::Const(name.into(), Box::new(init_value), pos))
|
|
}
|
|
// const name = expr - error
|
|
ScopeEntryType::Constant => {
|
|
Err(PERR::ForbiddenConstantExpr(name).into_err(init_value.position()))
|
|
}
|
|
}
|
|
} else {
|
|
// let name
|
|
Ok(Stmt::Let(name.into(), None, pos))
|
|
}
|
|
}
|
|
|
|
/// Parse a statement block.
|
|
fn parse_block<'a>(
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
breakable: bool,
|
|
allow_stmt_expr: bool,
|
|
) -> Result<Stmt, Box<ParseError>> {
|
|
// Must start with {
|
|
let pos = match input.next().unwrap() {
|
|
(Token::LeftBrace, pos) => pos,
|
|
(Token::LexError(err), pos) => return Err(PERR::BadInput(err.to_string()).into_err(pos)),
|
|
(_, pos) => {
|
|
return Err(
|
|
PERR::MissingToken("{".into(), "to start a statement block".into()).into_err(pos),
|
|
)
|
|
}
|
|
};
|
|
|
|
let mut statements = Vec::new();
|
|
|
|
while !match_token(input, 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().unwrap() {
|
|
// { ... stmt }
|
|
(Token::RightBrace, _) => {
|
|
eat_token(input, Token::RightBrace);
|
|
break;
|
|
}
|
|
// { ... stmt;
|
|
(Token::SemiColon, _) if need_semicolon => {
|
|
eat_token(input, Token::SemiColon);
|
|
}
|
|
// { ... { stmt } ;
|
|
(Token::SemiColon, _) if !need_semicolon => (),
|
|
// { ... { stmt } ???
|
|
(_, _) if !need_semicolon => (),
|
|
// { ... stmt <error>
|
|
(Token::LexError(err), pos) => {
|
|
return Err(PERR::BadInput(err.to_string()).into_err(*pos))
|
|
}
|
|
// { ... stmt ???
|
|
(_, pos) => {
|
|
// Semicolons are not optional between statements
|
|
return Err(
|
|
PERR::MissingToken(";".into(), "to terminate this statement".into())
|
|
.into_err(*pos),
|
|
);
|
|
}
|
|
}
|
|
}
|
|
|
|
Ok(Stmt::Block(statements, pos))
|
|
}
|
|
|
|
/// Parse an expression as a statement.
|
|
fn parse_expr_stmt<'a>(
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
allow_stmt_expr: bool,
|
|
) -> Result<Stmt, Box<ParseError>> {
|
|
let expr = parse_expr(input, allow_stmt_expr)?;
|
|
let expr = parse_op_assignment_stmt(input, expr, allow_stmt_expr)?;
|
|
Ok(Stmt::Expr(Box::new(expr)))
|
|
}
|
|
|
|
/// Parse a single statement.
|
|
fn parse_stmt<'a>(
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
breakable: bool,
|
|
allow_stmt_expr: bool,
|
|
) -> Result<Stmt, Box<ParseError>> {
|
|
let (token, pos) = match input.peek().unwrap() {
|
|
(Token::EOF, pos) => return Ok(Stmt::Noop(*pos)),
|
|
x => x,
|
|
};
|
|
|
|
match token {
|
|
// Semicolon - empty statement
|
|
Token::SemiColon => Ok(Stmt::Noop(*pos)),
|
|
|
|
Token::LeftBrace => parse_block(input, breakable, allow_stmt_expr),
|
|
|
|
// fn ...
|
|
#[cfg(not(feature = "no_function"))]
|
|
Token::Fn => Err(PERR::WrongFnDefinition.into_err(*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::Continue if breakable => {
|
|
let pos = eat_token(input, Token::Continue);
|
|
Ok(Stmt::Continue(pos))
|
|
}
|
|
Token::Break if breakable => {
|
|
let pos = eat_token(input, Token::Break);
|
|
Ok(Stmt::Break(pos))
|
|
}
|
|
Token::Continue | Token::Break => Err(PERR::LoopBreak.into_err(*pos)),
|
|
|
|
Token::Return | Token::Throw => {
|
|
let pos = *pos;
|
|
|
|
let return_type = match input.next().unwrap() {
|
|
(Token::Return, _) => ReturnType::Return,
|
|
(Token::Throw, _) => ReturnType::Exception,
|
|
_ => panic!("token should be return or throw"),
|
|
};
|
|
|
|
match input.peek().unwrap() {
|
|
// `return`/`throw` at <EOF>
|
|
(Token::EOF, pos) => Ok(Stmt::ReturnWithVal(None, return_type, *pos)),
|
|
// `return;` or `throw;`
|
|
(Token::SemiColon, _) => Ok(Stmt::ReturnWithVal(None, return_type, pos)),
|
|
// `return` or `throw` with expression
|
|
(_, _) => {
|
|
let expr = parse_expr(input, allow_stmt_expr)?;
|
|
let pos = expr.position();
|
|
Ok(Stmt::ReturnWithVal(Some(Box::new(expr)), return_type, pos))
|
|
}
|
|
}
|
|
}
|
|
|
|
Token::Let => parse_let(input, ScopeEntryType::Normal, allow_stmt_expr),
|
|
Token::Const => parse_let(input, ScopeEntryType::Constant, allow_stmt_expr),
|
|
|
|
_ => parse_expr_stmt(input, allow_stmt_expr),
|
|
}
|
|
}
|
|
|
|
/// Parse a function definition.
|
|
fn parse_fn<'a>(
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
allow_stmt_expr: bool,
|
|
) -> Result<FnDef, Box<ParseError>> {
|
|
let pos = input.next().expect("should be fn").1;
|
|
|
|
let name = match input.next().unwrap() {
|
|
(Token::Identifier(s), _) => s,
|
|
(_, pos) => return Err(PERR::FnMissingName.into_err(pos)),
|
|
};
|
|
|
|
match input.peek().unwrap() {
|
|
(Token::LeftParen, _) => eat_token(input, Token::LeftParen),
|
|
(_, pos) => return Err(PERR::FnMissingParams(name).into_err(*pos)),
|
|
};
|
|
|
|
let mut params = Vec::new();
|
|
|
|
if !match_token(input, Token::RightParen)? {
|
|
let end_err = format!("to close the parameters list of function '{}'", name);
|
|
let sep_err = format!("to separate the parameters of function '{}'", name);
|
|
|
|
loop {
|
|
match input.next().unwrap() {
|
|
(Token::Identifier(s), pos) => params.push((s, pos)),
|
|
(Token::LexError(err), pos) => {
|
|
return Err(PERR::BadInput(err.to_string()).into_err(pos))
|
|
}
|
|
(_, pos) => return Err(PERR::MissingToken(")".into(), end_err).into_err(pos)),
|
|
}
|
|
|
|
match input.next().unwrap() {
|
|
(Token::RightParen, _) => break,
|
|
(Token::Comma, _) => (),
|
|
(Token::Identifier(_), pos) => {
|
|
return Err(PERR::MissingToken(",".into(), sep_err).into_err(pos))
|
|
}
|
|
(Token::LexError(err), pos) => {
|
|
return Err(PERR::BadInput(err.to_string()).into_err(pos))
|
|
}
|
|
(_, pos) => return Err(PERR::MissingToken(",".into(), sep_err).into_err(pos)),
|
|
}
|
|
}
|
|
}
|
|
|
|
// Check for duplicating parameters
|
|
params
|
|
.iter()
|
|
.enumerate()
|
|
.try_for_each(|(i, (p1, _))| {
|
|
params
|
|
.iter()
|
|
.skip(i + 1)
|
|
.find(|(p2, _)| p2 == p1)
|
|
.map_or_else(|| Ok(()), |(p2, pos)| Err((p2, *pos)))
|
|
})
|
|
.map_err(|(p, pos)| {
|
|
PERR::FnDuplicatedParam(name.to_string(), p.to_string()).into_err(pos)
|
|
})?;
|
|
|
|
// Parse function body
|
|
let body = match input.peek().unwrap() {
|
|
(Token::LeftBrace, _) => parse_block(input, false, allow_stmt_expr)?,
|
|
(_, pos) => return Err(PERR::FnMissingBody(name).into_err(*pos)),
|
|
};
|
|
|
|
let params = params.into_iter().map(|(p, _)| p).collect();
|
|
|
|
Ok(FnDef {
|
|
name,
|
|
params,
|
|
body,
|
|
pos,
|
|
})
|
|
}
|
|
|
|
pub fn parse_global_expr<'a>(
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
engine: &Engine,
|
|
scope: &Scope,
|
|
optimization_level: OptimizationLevel,
|
|
) -> Result<AST, Box<ParseError>> {
|
|
let expr = parse_expr(input, false)?;
|
|
|
|
match input.peek().unwrap() {
|
|
(Token::EOF, _) => (),
|
|
// Return error if the expression doesn't end
|
|
(token, pos) => {
|
|
return Err(PERR::BadInput(format!("Unexpected '{}'", token.syntax())).into_err(*pos))
|
|
}
|
|
}
|
|
|
|
Ok(
|
|
// Optimize AST
|
|
optimize_into_ast(
|
|
engine,
|
|
scope,
|
|
vec![Stmt::Expr(Box::new(expr))],
|
|
vec![],
|
|
optimization_level,
|
|
),
|
|
)
|
|
}
|
|
|
|
/// Parse the global level statements.
|
|
fn parse_global_level<'a>(
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
) -> Result<(Vec<Stmt>, HashMap<u64, FnDef>), Box<ParseError>> {
|
|
let mut statements = Vec::<Stmt>::new();
|
|
let mut functions = HashMap::<u64, FnDef>::new();
|
|
|
|
while !input.peek().unwrap().0.is_eof() {
|
|
// Collect all the function definitions
|
|
#[cfg(not(feature = "no_function"))]
|
|
{
|
|
if let (Token::Fn, _) = input.peek().unwrap() {
|
|
let f = parse_fn(input, true)?;
|
|
functions.insert(calc_fn_def(&f.name, f.params.len()), f);
|
|
continue;
|
|
}
|
|
}
|
|
|
|
// Actual statement
|
|
let stmt = parse_stmt(input, false, true)?;
|
|
|
|
let need_semicolon = !stmt.is_self_terminated();
|
|
|
|
statements.push(stmt);
|
|
|
|
match input.peek().unwrap() {
|
|
// EOF
|
|
(Token::EOF, _) => break,
|
|
// stmt ;
|
|
(Token::SemiColon, _) if need_semicolon => {
|
|
eat_token(input, Token::SemiColon);
|
|
}
|
|
// stmt ;
|
|
(Token::SemiColon, _) if !need_semicolon => (),
|
|
// { stmt } ???
|
|
(_, _) if !need_semicolon => (),
|
|
// stmt <error>
|
|
(Token::LexError(err), pos) => {
|
|
return Err(PERR::BadInput(err.to_string()).into_err(*pos))
|
|
}
|
|
// stmt ???
|
|
(_, pos) => {
|
|
// Semicolons are not optional between statements
|
|
return Err(
|
|
PERR::MissingToken(";".into(), "to terminate this statement".into())
|
|
.into_err(*pos),
|
|
);
|
|
}
|
|
}
|
|
}
|
|
|
|
Ok((statements, functions))
|
|
}
|
|
|
|
/// Run the parser on an input stream, returning an AST.
|
|
pub fn parse<'a>(
|
|
input: &mut Peekable<TokenIterator<'a>>,
|
|
engine: &Engine,
|
|
scope: &Scope,
|
|
optimization_level: OptimizationLevel,
|
|
) -> Result<AST, Box<ParseError>> {
|
|
let (statements, functions) = parse_global_level(input)?;
|
|
|
|
let fn_lib = functions.into_iter().map(|(_, v)| v).collect();
|
|
Ok(
|
|
// Optimize AST
|
|
optimize_into_ast(engine, scope, statements, fn_lib, optimization_level),
|
|
)
|
|
}
|
|
|
|
/// 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> {
|
|
match value.0 {
|
|
Union::Unit(_) => Some(Expr::Unit(pos)),
|
|
Union::Int(value) => Some(Expr::IntegerConstant(value, pos)),
|
|
Union::Char(value) => Some(Expr::CharConstant(value, pos)),
|
|
Union::Str(value) => Some(Expr::StringConstant((*value).into(), pos)),
|
|
Union::Bool(true) => Some(Expr::True(pos)),
|
|
Union::Bool(false) => Some(Expr::False(pos)),
|
|
#[cfg(not(feature = "no_index"))]
|
|
Union::Array(array) => {
|
|
let items: Vec<_> = array
|
|
.into_iter()
|
|
.map(|x| map_dynamic_to_expr(x, pos))
|
|
.collect();
|
|
|
|
if items.iter().all(Option::is_some) {
|
|
Some(Expr::Array(
|
|
items.into_iter().map(Option::unwrap).collect(),
|
|
pos,
|
|
))
|
|
} else {
|
|
None
|
|
}
|
|
}
|
|
#[cfg(not(feature = "no_object"))]
|
|
Union::Map(map) => {
|
|
let items: Vec<_> = map
|
|
.into_iter()
|
|
.map(|(k, v)| (k, map_dynamic_to_expr(v, pos), pos))
|
|
.collect();
|
|
if items.iter().all(|(_, expr, _)| expr.is_some()) {
|
|
Some(Expr::Map(
|
|
items
|
|
.into_iter()
|
|
.map(|(k, expr, pos)| (k, expr.unwrap(), pos))
|
|
.collect(),
|
|
pos,
|
|
))
|
|
} else {
|
|
None
|
|
}
|
|
}
|
|
#[cfg(not(feature = "no_float"))]
|
|
Union::Float(value) => Some(Expr::FloatConstant(value, pos)),
|
|
|
|
_ => None,
|
|
}
|
|
}
|