53 lines
2.3 KiB
Rust
53 lines
2.3 KiB
Rust
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use crate::{compile::Compile, obj::prelude::*, syn::{ast::*, visit::*}};
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/// Collects local names from the given tree.
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///
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/// This will *not* attempt to recursively collect locals, and will only stay on the base statement
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/// level.
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pub struct CollectLocals<'c, 't> {
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compile: &'c mut Compile<'t>,
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}
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// - Python's LEGB methodology seems to be good. Look up variables in this order:
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// - Local
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// - Enclosing functions (i.e. inner functions)
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// - Global
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// - Builtin
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// - Resolving names:
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// - Scan assignments first. If anything is assigned (even before usage), it's local.
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// - Everything else should just do a lookup
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impl<'c, 't> CollectLocals<'c, 't> {
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pub fn new(compile: &'c mut Compile<'t>) -> Self {
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Self { compile }
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}
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pub fn collect(&mut self, body: &Body) {
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self.visit_body(body)
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}
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}
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impl Visit for CollectLocals<'_, '_> {
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type Out = ();
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fn visit_body(&mut self, body: &Body) -> Self::Out { DefaultAccept::default_accept(body, self); }
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fn visit_stmt(&mut self, stmt: &Stmt) -> Self::Out { DefaultAccept::default_accept(stmt, self); }
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fn visit_assign_stmt(&mut self, assign: &AssignStmt) -> Self::Out { DefaultAccept::default_accept(assign, self); }
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fn visit_lhs_expr(&mut self, lhs_expr: &LhsExpr) -> Self::Out {
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match lhs_expr {
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LhsExpr::Local(name) => {
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let sym = global_sym(name.to_string());
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self.compile.create_local(sym);
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}
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_ => { /* no op */ }
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}
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}
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fn visit_expr(&mut self, expr: &Expr) -> Self::Out { DefaultAccept::default_accept(expr, self); }
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fn visit_bin_expr(&mut self, expr: &BinExpr) -> Self::Out { DefaultAccept::default_accept(expr, self); }
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fn visit_un_expr(&mut self, expr: &UnExpr) -> Self::Out { DefaultAccept::default_accept(expr, self); }
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fn visit_call_expr(&mut self, expr: &CallExpr) -> Self::Out { DefaultAccept::default_accept(expr, self); }
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fn visit_index_expr(&mut self, expr: &IndexExpr) -> Self::Out { DefaultAccept::default_accept(expr, self); }
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fn visit_access_expr(&mut self, expr: &AccessExpr) -> Self::Out { DefaultAccept::default_accept(expr, self); }
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fn visit_atom(&mut self, atom: &Atom) -> Self::Out { DefaultAccept::default_accept(atom, self); }
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}
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