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Optimize chain structure.

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Stephen Chung 2023-04-22 12:42:50 +08:00
parent f49ce33a88
commit a0869004a3
1 changed files with 67 additions and 0 deletions
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67
src/optimizer.rs
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@ -857,6 +857,63 @@ fn optimize_stmt(stmt: &mut Stmt, state: &mut OptimizerState, preserve_result: b
}
}
/// Optimize the structure of a chained expression.
#[cfg(any(not(feature = "no_index"), not(feature = "no_object")))]
fn optimize_chain_structure(expr: &mut Expr, state: &mut OptimizerState) {
let (mut x, options, pos, mut lhs_x, mut lhs_options, lhs_pos, sub, root): (
_,
_,
_,
_,
_,
_,
fn(_, _, _) -> Expr,
fn(_, _, _) -> Expr,
) = match expr.take() {
#[cfg(not(feature = "no_index"))]
Expr::Index(mut x, opt, pos) => match x.lhs.take() {
Expr::Index(x2, opt2, pos2) => (x, opt, pos, x2, opt2, pos2, Expr::Index, Expr::Index),
#[cfg(not(feature = "no_object"))]
Expr::Dot(x2, opt2, pos2) => (x, opt, pos, x2, opt2, pos2, Expr::Index, Expr::Dot),
_ => return,
},
#[cfg(not(feature = "no_object"))]
Expr::Dot(mut x, opt, pos) => match x.lhs.take() {
#[cfg(not(feature = "no_index"))]
Expr::Index(x2, opt2, pos2) => (x, opt, pos, x2, opt2, pos2, Expr::Dot, Expr::Index),
Expr::Dot(x2, opt2, pos2) => (x, opt, pos, x2, opt2, pos2, Expr::Dot, Expr::Index),
_ => return,
},
_ => return,
};
// Find the end of the chain
let mut last_node = lhs_x.as_mut();
let mut last_options = &mut lhs_options;
while !last_options.contains(ASTFlags::BREAK) {
match last_node.rhs {
Expr::Index(ref mut x, ref mut options2, ..) => {
last_node = x.as_mut();
last_options = options2;
}
#[cfg(not(feature = "no_object"))]
Expr::Dot(ref mut x, ref mut options2, ..) => {
last_node = x.as_mut();
last_options = options2;
}
_ => break,
}
}
last_options.remove(ASTFlags::BREAK);
x.lhs = last_node.rhs.take();
last_node.rhs = sub(x, options, pos);
*expr = root(lhs_x, lhs_options, lhs_pos);
state.set_dirty();
}
/// Optimize an [expression][Expr].
fn optimize_expr(expr: &mut Expr, state: &mut OptimizerState, _chaining: bool) {
// These keywords are handled specially
@ -922,6 +979,11 @@ fn optimize_expr(expr: &mut Expr, state: &mut OptimizerState, _chaining: bool) {
*expr = Expr::from_dynamic(Dynamic::FALSE, *pos);
}
}
#[cfg(not(feature = "no_index"))]
// (lhs_lhs[lhs_rhs])[rhs]
(Expr::Index(..), ..) => optimize_chain_structure(expr, state),
// (lhs_lhs[lhs_rhs]).rhs
(Expr::Dot(..), ..) => optimize_chain_structure(expr, state),
// lhs.rhs
(lhs, rhs) => { optimize_expr(lhs, state, false); optimize_expr(rhs, state, true); }
}
@ -992,6 +1054,11 @@ fn optimize_expr(expr: &mut Expr, state: &mut OptimizerState, _chaining: bool) {
}
// var[rhs]
(Expr::Variable(..), rhs) => optimize_expr(rhs, state, true),
// (lhs_lhs[lhs_rhs])[rhs]
(Expr::Index(..), ..) => optimize_chain_structure(expr, state),
// (lhs_lhs[lhs_rhs]).rhs
#[cfg(not(feature = "no_object"))]
(Expr::Dot(..), ..) => optimize_chain_structure(expr, state),
// lhs[rhs]
(lhs, rhs) => { optimize_expr(lhs, state, false); optimize_expr(rhs, state, true); }
},