kjuulh/rhai
1
0
Fork 0
Code Issues 1 Pull Requests 1 Packages Projects Releases Wiki Activity

Use option flags for certain AST nodes.

Browse Source
This commit is contained in:
Stephen Chung 2021-09-10 20:23:59 +08:00
parent 7956f9d59c
commit 43de522568
6 changed files with 124 additions and 114 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
CHANGELOG.md
View File

@ -44,6 +44,8 @@ Enhancements
### `AST` API
* Added `ASTNode::position`.
* `ReturnType` is removed in favor of option flags for `Stmt::Return`.
* `Stmt::Break` and `Stmt::Continue` are merged into `Stmt::BreakLoop` via an option flag.
Version 1.0.4

93
src/ast.rs
View File

@ -837,20 +837,6 @@ impl fmt::Debug for Ident {
}
}
/// _(internals)_ A type encapsulating the mode of a `return`/`throw` statement.
/// Exported under the `internals` feature only.
///
/// # Volatile Data Structure
///
/// This type is volatile and may change.
#[derive(Debug, Eq, PartialEq, Clone, Copy, Hash)]
pub enum ReturnType {
/// `return` statement.
Return,
/// `throw` statement.
Exception,
}
/// _(internals)_ An [`AST`] node, consisting of either an [`Expr`] or a [`Stmt`].
/// Exported under the `internals` feature only.
///
@ -859,7 +845,9 @@ pub enum ReturnType {
/// This type is volatile and may change.
#[derive(Debug, Clone, Hash)]
pub enum ASTNode<'a> {
/// A statement ([`Stmt`]).
Stmt(&'a Stmt),
/// An expression ([`Expr`]).
Expr(&'a Expr),
}
@ -885,7 +873,7 @@ impl ASTNode<'_> {
}
}
/// _(internals)_ A statements block.
/// _(internals)_ A scoped block of statements.
/// Exported under the `internals` feature only.
///
/// # Volatile Data Structure
@ -914,18 +902,12 @@ impl StmtBlock {
pub fn len(&self) -> usize {
self.0.len()
}
/// Get the position of this statements block.
/// Get the position (location of the beginning `{`) of this statements block.
#[inline(always)]
#[must_use]
pub const fn position(&self) -> Position {
self.1
}
/// Get the statements of this statements block.
#[inline(always)]
#[must_use]
pub fn statements_mut(&mut self) -> &mut StaticVec<Stmt> {
&mut self.0
}
}
impl Deref for StmtBlock {
@ -1026,12 +1008,15 @@ pub mod AST_OPTION_FLAGS {
/// _(internals)_ The [`AST`][crate::AST] node is constant.
/// Exported under the `internals` feature only.
pub const AST_OPTION_CONSTANT: OptionFlags = OptionFlags(0b0000_0001);
/// _(internals)_ The [`AST`][crate::AST] node is exported.
/// _(internals)_ The [`AST`][crate::AST] node is public.
/// Exported under the `internals` feature only.
pub const AST_OPTION_EXPORTED: OptionFlags = OptionFlags(0b0000_0010);
pub const AST_OPTION_PUBLIC: OptionFlags = OptionFlags(0b0000_0010);
/// _(internals)_ The [`AST`][crate::AST] node is in negated mode.
/// Exported under the `internals` feature only.
pub const AST_OPTION_NEGATED: OptionFlags = OptionFlags(0b0000_0100);
/// _(internals)_ The [`AST`][crate::AST] node breaks out of normal control flow.
/// Exported under the `internals` feature only.
pub const AST_OPTION_BREAK_OUT: OptionFlags = OptionFlags(0b0000_1000);
impl std::fmt::Debug for OptionFlags {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
@ -1056,8 +1041,9 @@ pub mod AST_OPTION_FLAGS {
f.write_str("(")?;
write_option(self, f, num_flags, AST_OPTION_CONSTANT, "Constant")?;
write_option(self, f, num_flags, AST_OPTION_EXPORTED, "Exported")?;
write_option(self, f, num_flags, AST_OPTION_PUBLIC, "Public")?;
write_option(self, f, num_flags, AST_OPTION_NEGATED, "Negated")?;
write_option(self, f, num_flags, AST_OPTION_BREAK_OUT, "Break")?;
f.write_str(")")?;
Ok(())
@ -1100,7 +1086,7 @@ pub enum Stmt {
///
/// ### Option Flags
///
/// * [`AST_FLAG_EXPORTED`][AST_FLAGS::AST_FLAG_EXPORTED] = `export`
/// * [`AST_FLAG_PUBLIC`][AST_FLAGS::AST_FLAG_PUBLIC] = `export`
/// * [`AST_FLAG_CONSTANT`][AST_FLAGS::AST_FLAG_CONSTANT] = `const`
Var(Expr, Box<Ident>, OptionFlags, Position),
/// expr op`=` expr
@ -1116,12 +1102,20 @@ pub enum Stmt {
TryCatch(Box<(StmtBlock, Option<Ident>, StmtBlock)>, Position),
/// [expression][Expr]
Expr(Expr),
/// `continue`
Continue(Position),
/// `break`
Break(Position),
/// `continue`/`break`
///
/// ### Option Flags
///
/// * [`AST_FLAG_NONE`][AST_FLAGS::AST_FLAG_NONE] = `continue`
/// * [`AST_FLAG_BREAK_OUT`][AST_FLAGS::AST_FLAG_BREAK_OUT] = `break`
BreakLoop(OptionFlags, Position),
/// `return`/`throw`
Return(ReturnType, Option<Expr>, Position),
///
/// ### Option Flags
///
/// * [`AST_FLAG_NONE`][AST_FLAGS::AST_FLAG_NONE] = `return`
/// * [`AST_FLAG_BREAK_OUT`][AST_FLAGS::AST_FLAG_BREAK_OUT] = `throw`
Return(OptionFlags, Option<Expr>, Position),
/// `import` expr `as` var
///
/// Not available under `no_module`.
@ -1135,6 +1129,11 @@ pub enum Stmt {
/// Convert a variable to shared.
///
/// Not available under `no_closure`.
///
/// # Notes
///
/// This variant does not map to any language structure. It is currently only used only to
/// convert a normal variable into a shared variable when the variable is _captured_ by a closure.
#[cfg(not(feature = "no_closure"))]
Share(Identifier),
}
@ -1172,8 +1171,7 @@ impl Stmt {
pub const fn position(&self) -> Position {
match self {
Self::Noop(pos)
| Self::Continue(pos)
| Self::Break(pos)
| Self::BreakLoop(_, pos)
| Self::Block(_, pos)
| Self::Assignment(_, pos)
| Self::FnCall(_, pos)
@ -1201,8 +1199,7 @@ impl Stmt {
pub fn set_position(&mut self, new_pos: Position) -> &mut Self {
match self {
Self::Noop(pos)
| Self::Continue(pos)
| Self::Break(pos)
| Self::BreakLoop(_, pos)
| Self::Block(_, pos)
| Self::Assignment(_, pos)
| Self::FnCall(_, pos)
@ -1248,8 +1245,7 @@ impl Stmt {
Self::Var(_, _, _, _)
| Self::Assignment(_, _)
| Self::Continue(_)
| Self::Break(_)
| Self::BreakLoop(_, _)
| Self::Return(_, _, _) => false,
#[cfg(not(feature = "no_module"))]
@ -1280,8 +1276,7 @@ impl Stmt {
| Self::Expr(_)
| Self::FnCall(_, _)
| Self::Do(_, _, _, _)
| Self::Continue(_)
| Self::Break(_)
| Self::BreakLoop(_, _)
| Self::Return(_, _, _) => false,
#[cfg(not(feature = "no_module"))]
@ -1330,7 +1325,7 @@ impl Stmt {
Self::Var(_, _, _, _) | Self::Assignment(_, _) | Self::FnCall(_, _) => false,
Self::Block(block, _) => block.iter().all(|stmt| stmt.is_pure()),
Self::Continue(_) | Self::Break(_) | Self::Return(_, _, _) => false,
Self::BreakLoop(_, _) | Self::Return(_, _, _) => false,
Self::TryCatch(x, _) => {
(x.0).0.iter().all(Stmt::is_pure) && (x.2).0.iter().all(Stmt::is_pure)
}
@ -1348,8 +1343,8 @@ impl Stmt {
///
/// An internally pure statement only has side effects that disappear outside the block.
///
/// Only variable declarations (i.e. `let` and `const`) and `import`/`export` statements
/// are internally pure.
/// Currently only variable declarations (i.e. `let` and `const`) and `import`/`export`
/// statements are internally pure.
#[inline]
#[must_use]
pub fn is_internally_pure(&self) -> bool {
@ -1373,7 +1368,7 @@ impl Stmt {
#[must_use]
pub const fn is_control_flow_break(&self) -> bool {
match self {
Self::Return(_, _, _) | Self::Break(_) | Self::Continue(_) => true,
Self::Return(_, _, _) | Self::BreakLoop(_, _) => true,
_ => false,
}
}
@ -1516,7 +1511,8 @@ impl Stmt {
pub struct CustomExpr {
/// List of keywords.
pub keywords: StaticVec<Expr>,
/// Is the current [`Scope`][crate::Scope] modified?
/// Is the current [`Scope`][crate::Scope] possibly modified by this custom statement
/// (e.g. introducing a new variable)?
pub scope_may_be_changed: bool,
/// List of tokens actually parsed.
pub tokens: StaticVec<Identifier>,
@ -1689,6 +1685,9 @@ pub struct FnCallExpr {
/// List of function call argument expressions.
pub args: StaticVec<Expr>,
/// List of function call arguments that are constants.
///
/// Any arguments in `args` that is [`Expr::Stack`][Expr::Stack] indexes into this
/// array to find the constant for use as its argument value.
pub constants: smallvec::SmallVec<[Dynamic; 2]>,
/// Function name.
pub name: Identifier,
@ -1889,6 +1888,12 @@ pub enum Expr {
)>,
),
/// Stack slot
///
/// # Notes
///
/// This variant does not map to any language structure. It is currently only used in function
/// calls with constant arguments where the `usize` number indexes into an array containing a
/// list of constant arguments for the function call. See [`FnCallExpr`] for more details.
Stack(usize, Position),
/// { [statement][Stmt] ... }
Stmt(Box<StmtBlock>),

47
src/engine.rs
View File

@ -1,6 +1,6 @@
//! Main module defining the script evaluation [`Engine`].
use crate::ast::{Expr, FnCallExpr, Ident, OpAssignment, ReturnType, Stmt, AST_OPTION_FLAGS::*};
use crate::ast::{Expr, FnCallExpr, Ident, OpAssignment, Stmt, AST_OPTION_FLAGS::*};
use crate::custom_syntax::CustomSyntax;
use crate::dynamic::{map_std_type_name, AccessMode, Union, Variant};
use crate::fn_hash::get_hasher;
@ -2704,11 +2704,10 @@ impl Engine {
}
}
// Continue statement
Stmt::Continue(pos) => EvalAltResult::LoopBreak(false, *pos).into(),
// Break statement
Stmt::Break(pos) => EvalAltResult::LoopBreak(true, *pos).into(),
// Continue/Break statement
Stmt::BreakLoop(options, pos) => {
EvalAltResult::LoopBreak(options.contains(AST_OPTION_BREAK_OUT), *pos).into()
}
// Namespace-qualified function call
Stmt::FnCall(x, pos) if x.is_qualified() => {
@ -2828,8 +2827,23 @@ impl Engine {
}
}
// Throw value
Stmt::Return(options, Some(expr), pos) if options.contains(AST_OPTION_BREAK_OUT) => {
EvalAltResult::ErrorRuntime(
self.eval_expr(scope, mods, state, lib, this_ptr, expr, level)?
.flatten(),
*pos,
)
.into()
}
// Empty throw
Stmt::Return(options, None, pos) if options.contains(AST_OPTION_BREAK_OUT) => {
EvalAltResult::ErrorRuntime(Dynamic::UNIT, *pos).into()
}
// Return value
Stmt::Return(ReturnType::Return, Some(expr), pos) => EvalAltResult::Return(
Stmt::Return(_, Some(expr), pos) => EvalAltResult::Return(
self.eval_expr(scope, mods, state, lib, this_ptr, expr, level)?
.flatten(),
*pos,
@ -2837,22 +2851,7 @@ impl Engine {
.into(),
// Empty return
Stmt::Return(ReturnType::Return, None, pos) => {
EvalAltResult::Return(Dynamic::UNIT, *pos).into()
}
// Throw value
Stmt::Return(ReturnType::Exception, Some(expr), pos) => EvalAltResult::ErrorRuntime(
self.eval_expr(scope, mods, state, lib, this_ptr, expr, level)?
.flatten(),
*pos,
)
.into(),
// Empty throw
Stmt::Return(ReturnType::Exception, None, pos) => {
EvalAltResult::ErrorRuntime(Dynamic::UNIT, *pos).into()
}
Stmt::Return(_, None, pos) => EvalAltResult::Return(Dynamic::UNIT, *pos).into(),
// Let/const statement
Stmt::Var(expr, x, options, _) => {
@ -2862,7 +2861,7 @@ impl Engine {
} else {
AccessMode::ReadWrite
};
let export = options.contains(AST_OPTION_EXPORTED);
let export = options.contains(AST_OPTION_PUBLIC);
let value = self
.eval_expr(scope, mods, state, lib, this_ptr, expr, level)?

2
src/lib.rs
View File

@ -230,7 +230,7 @@ pub use token::{InputStream, Token, TokenizeState, TokenizerControl, TokenizerCo
#[deprecated = "this type is volatile and may change"]
pub use ast::{
ASTNode, BinaryExpr, CustomExpr, Expr, FloatWrapper, FnCallExpr, FnCallHashes, Ident,
OpAssignment, OptionFlags, ReturnType, ScriptFnDef, Stmt, StmtBlock, AST_OPTION_FLAGS::*,
OpAssignment, OptionFlags, ScriptFnDef, Stmt, StmtBlock, AST_OPTION_FLAGS::*,
};
#[cfg(feature = "internals")]

80
src/optimize.rs
View File

@ -16,6 +16,7 @@ use std::{
any::TypeId,
hash::{Hash, Hasher},
mem,
ops::DerefMut,
};
#[cfg(not(feature = "no_closure"))]
@ -267,7 +268,9 @@ fn optimize_stmt_block(
loop {
match statements[..] {
// { return; } -> {}
[Stmt::Return(crate::ast::ReturnType::Return, None, _)] if reduce_return => {
[Stmt::Return(options, None, _)]
if reduce_return && !options.contains(AST_OPTION_BREAK_OUT) =>
{
state.set_dirty();
statements.clear();
}
@ -276,8 +279,10 @@ fn optimize_stmt_block(
statements.clear();
}
// { ...; return; } -> { ... }
[.., ref last_stmt, Stmt::Return(crate::ast::ReturnType::Return, None, _)]
if reduce_return && !last_stmt.returns_value() =>
[.., ref last_stmt, Stmt::Return(options, None, _)]
if reduce_return
&& !options.contains(AST_OPTION_BREAK_OUT)
&& !last_stmt.returns_value() =>
{
state.set_dirty();
statements
@ -285,8 +290,8 @@ fn optimize_stmt_block(
.expect("`statements` contains at least two elements");
}
// { ...; return val; } -> { ...; val }
[.., Stmt::Return(crate::ast::ReturnType::Return, ref mut expr, pos)]
if reduce_return =>
[.., Stmt::Return(options, ref mut expr, pos)]
if reduce_return && !options.contains(AST_OPTION_BREAK_OUT) =>
{
state.set_dirty();
*statements
@ -332,8 +337,8 @@ fn optimize_stmt_block(
statements.clear();
}
// { ...; return; } -> { ... }
[.., Stmt::Return(crate::ast::ReturnType::Return, None, _)]
if reduce_return =>
[.., Stmt::Return(options, None, _)]
if reduce_return && !options.contains(AST_OPTION_BREAK_OUT) =>
{
state.set_dirty();
statements
@ -341,8 +346,10 @@ fn optimize_stmt_block(
.expect("`statements` contains at least two elements");
}
// { ...; return pure_val; } -> { ... }
[.., Stmt::Return(crate::ast::ReturnType::Return, Some(ref expr), _)]
if reduce_return && expr.is_pure() =>
[.., Stmt::Return(options, Some(ref expr), _)]
if reduce_return
&& !options.contains(AST_OPTION_BREAK_OUT)
&& expr.is_pure() =>
{
state.set_dirty();
statements
@ -467,12 +474,10 @@ fn optimize_stmt(stmt: &mut Stmt, state: &mut OptimizerState, preserve_result: b
// if expr { if_block } else { else_block }
Stmt::If(condition, x, _) => {
optimize_expr(condition, state, false);
let if_block = mem::take(x.0.statements_mut()).into_vec();
*x.0.statements_mut() =
optimize_stmt_block(if_block, state, preserve_result, true, false).into();
let else_block = mem::take(x.1.statements_mut()).into_vec();
*x.1.statements_mut() =
optimize_stmt_block(else_block, state, preserve_result, true, false).into();
let if_block = mem::take(x.0.deref_mut()).into_vec();
*x.0 = optimize_stmt_block(if_block, state, preserve_result, true, false).into();
let else_block = mem::take(x.1.deref_mut()).into_vec();
*x.1 = optimize_stmt_block(else_block, state, preserve_result, true, false).into();
}
// switch const { ... }
@ -545,8 +550,8 @@ fn optimize_stmt(stmt: &mut Stmt, state: &mut OptimizerState, preserve_result: b
_ => {
block.0 = Some(condition);
*block.1.statements_mut() = optimize_stmt_block(
mem::take(block.1.statements_mut()).into_vec(),
*block.1 = optimize_stmt_block(
mem::take(block.1.deref_mut()).into_vec(),
state,
preserve_result,
true,
@ -566,9 +571,8 @@ fn optimize_stmt(stmt: &mut Stmt, state: &mut OptimizerState, preserve_result: b
x.0.remove(&key);
}
let def_block = mem::take(x.1.statements_mut()).into_vec();
*x.1.statements_mut() =
optimize_stmt_block(def_block, state, preserve_result, true, false).into();
let def_block = mem::take(x.1.deref_mut()).into_vec();
*x.1 = optimize_stmt_block(def_block, state, preserve_result, true, false).into();
}
// while false { block } -> Noop
@ -582,13 +586,14 @@ fn optimize_stmt(stmt: &mut Stmt, state: &mut OptimizerState, preserve_result: b
if let Expr::BoolConstant(true, pos) = condition {
*condition = Expr::Unit(*pos);
}
let block = mem::take(body.statements_mut()).into_vec();
*body.statements_mut() = optimize_stmt_block(block, state, false, true, false).into();
let block = mem::take(body.as_mut().deref_mut()).into_vec();
*body.as_mut().deref_mut() =
optimize_stmt_block(block, state, false, true, false).into();
if body.len() == 1 {
match body[0] {
// while expr { break; } -> { expr; }
Stmt::Break(pos) => {
Stmt::BreakLoop(options, pos) if options.contains(AST_OPTION_BREAK_OUT) => {
// Only a single break statement - turn into running the guard expression once
state.set_dirty();
if !condition.is_unit() {
@ -611,7 +616,7 @@ fn optimize_stmt(stmt: &mut Stmt, state: &mut OptimizerState, preserve_result: b
{
state.set_dirty();
let block_pos = body.position();
let block = mem::take(body.statements_mut()).into_vec();
let block = mem::take(body.as_mut().deref_mut()).into_vec();
*stmt = Stmt::Block(
optimize_stmt_block(block, state, false, true, false).into_boxed_slice(),
block_pos,
@ -620,14 +625,15 @@ fn optimize_stmt(stmt: &mut Stmt, state: &mut OptimizerState, preserve_result: b
// do { block } while|until expr
Stmt::Do(body, condition, _, _) => {
optimize_expr(condition, state, false);
let block = mem::take(body.statements_mut()).into_vec();
*body.statements_mut() = optimize_stmt_block(block, state, false, true, false).into();
let block = mem::take(body.as_mut().deref_mut()).into_vec();
*body.as_mut().deref_mut() =
optimize_stmt_block(block, state, false, true, false).into();
}
// for id in expr { block }
Stmt::For(iterable, x, _) => {
optimize_expr(iterable, state, false);
let body = mem::take(x.2.statements_mut()).into_vec();
*x.2.statements_mut() = optimize_stmt_block(body, state, false, true, false).into();
let body = mem::take(x.2.deref_mut()).into_vec();
*x.2 = optimize_stmt_block(body, state, false, true, false).into();
}
// let id = expr;
Stmt::Var(expr, _, options, _) if !options.contains(AST_OPTION_CONSTANT) => {
@ -667,12 +673,10 @@ fn optimize_stmt(stmt: &mut Stmt, state: &mut OptimizerState, preserve_result: b
}
// try { try_block } catch ( var ) { catch_block }
Stmt::TryCatch(x, _) => {
let try_block = mem::take(x.0.statements_mut()).into_vec();
*x.0.statements_mut() =
optimize_stmt_block(try_block, state, false, true, false).into();
let catch_block = mem::take(x.2.statements_mut()).into_vec();
*x.2.statements_mut() =
optimize_stmt_block(catch_block, state, false, true, false).into();
let try_block = mem::take(x.0.deref_mut()).into_vec();
*x.0 = optimize_stmt_block(try_block, state, false, true, false).into();
let catch_block = mem::take(x.2.deref_mut()).into_vec();
*x.2 = optimize_stmt_block(catch_block, state, false, true, false).into();
}
// func(...)
Stmt::Expr(expr @ Expr::FnCall(_, _)) => {
@ -721,7 +725,8 @@ fn optimize_expr(expr: &mut Expr, state: &mut OptimizerState, chaining: bool) {
Expr::Stmt(x) if x.is_empty() => { state.set_dirty(); *expr = Expr::Unit(x.position()) }
// { stmt; ... } - do not count promotion as dirty because it gets turned back into an array
Expr::Stmt(x) => {
*x.statements_mut() = optimize_stmt_block(mem::take(x.statements_mut()).into_vec(), state, true, true, false).into();
*x.as_mut().deref_mut() =
optimize_stmt_block(mem::take(x.as_mut().deref_mut()).into_vec(), state, true, true, false).into();
// { Stmt(Expr) } - promote
match x.as_mut().as_mut() {
@ -1171,10 +1176,9 @@ pub fn optimize_into_ast(
// Optimize the function body
let state = &mut OptimizerState::new(engine, lib2, level);
let body = mem::take(fn_def.body.statements_mut()).into_vec();
let body = mem::take(fn_def.body.deref_mut()).into_vec();
*fn_def.body.statements_mut() =
optimize_stmt_block(body, state, true, true, true).into();
*fn_def.body = optimize_stmt_block(body, state, true, true, true).into();
fn_def
})

14
src/parse.rs
View File

@ -1,8 +1,8 @@
//! Main module defining the lexer and parser.
use crate::ast::{
BinaryExpr, CustomExpr, Expr, FnCallExpr, FnCallHashes, Ident, OpAssignment, ReturnType,
ScriptFnDef, Stmt, StmtBlock, AST_OPTION_FLAGS::*,
BinaryExpr, CustomExpr, Expr, FnCallExpr, FnCallHashes, Ident, OpAssignment, ScriptFnDef, Stmt,
StmtBlock, AST_OPTION_FLAGS::*,
};
use crate::custom_syntax::{markers::*, CustomSyntax};
use crate::dynamic::AccessMode;
@ -2428,7 +2428,7 @@ fn parse_let(
state.stack.push((name, var_type));
let export = if is_export {
AST_OPTION_EXPORTED
AST_OPTION_PUBLIC
} else {
AST_OPTION_NONE
};
@ -2829,11 +2829,11 @@ fn parse_stmt(
Token::Continue if settings.is_breakable => {
let pos = eat_token(input, Token::Continue);
Ok(Stmt::Continue(pos))
Ok(Stmt::BreakLoop(AST_OPTION_NONE, pos))
}
Token::Break if settings.is_breakable => {
let pos = eat_token(input, Token::Break);
Ok(Stmt::Break(pos))
Ok(Stmt::BreakLoop(AST_OPTION_BREAK_OUT, pos))
}
Token::Continue | Token::Break => Err(PERR::LoopBreak.into_err(settings.pos)),
@ -2843,8 +2843,8 @@ fn parse_stmt(
.map(|(token, pos)| {
(
match token {
Token::Return => ReturnType::Return,
Token::Throw => ReturnType::Exception,
Token::Return => AST_OPTION_NONE,
Token::Throw => AST_OPTION_BREAK_OUT,
_ => unreachable!(),
},
pos,