73 lines
1.6 KiB
Rust
73 lines
1.6 KiB
Rust
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use std::io::Write;
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use std::collections::HashSet;
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use crate::parser;
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pub struct LexicalContext<'a> {
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parent: Option<&'a LexicalContext<'a>>,
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local: HashSet<String>
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}
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impl <'a> LexicalContext<'a> {
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pub fn toplevel() -> Self {
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LexicalContext {
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parent: None,
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local: HashSet::new()
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}
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}
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#[allow(dead_code)]
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fn new(parent: &'a LexicalContext<'a>) -> Self {
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LexicalContext {
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parent: Some(parent),
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local: HashSet::new(),
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}
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}
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fn contains(&self, s: &str) -> bool {
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self.local.contains(s) || self.parent.map_or(false, |c| c.contains(s))
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}
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fn insert(&mut self, s: String) -> bool {
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self.local.insert(s)
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}
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}
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pub fn emit_all(w: &mut dyn Write, ast: &Vec<parser::Stmt>, ctx: &mut LexicalContext) -> std::io::Result<()> {
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for stmt in ast {
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emit(w, stmt, ctx)?;
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}
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Ok(())
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}
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pub fn emit(w: &mut dyn Write, stmt: &parser::Stmt, ctx: &mut LexicalContext) -> std::io::Result<()> {
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match &stmt {
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parser::Stmt::ReplPrint(expr) => {
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write!(w, "console.log((")?;
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emit_expr(w, expr, ctx)?;
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writeln!(w, "));")?;
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}
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parser::Stmt::Assignment(id, expr) => {
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if !ctx.contains(id) {
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ctx.insert(id.clone());
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write!(w, "let ")?;
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}
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write!(w, "{} = ", id)?;
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emit_expr(w, expr, ctx)?;
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writeln!(w, ";")?;
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}
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_ => todo!(),
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}
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Ok(())
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}
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pub fn emit_expr(w: &mut dyn Write, expr: &parser::Expr, ctx: &mut LexicalContext) -> std::io::Result<()> {
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match &expr {
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parser::Expr::Id(id) => {
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write!(w, "{}", id)?;
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}
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parser::Expr::Atom(atom) => {
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write!(w, "{}", atom)?;
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}
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_ => todo!(),
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}
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Ok(())
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}
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