From 1b826430f0e2771eccbf458bf6312776f54c84fb Mon Sep 17 00:00:00 2001
From: Nick Krichevsky <nick@ollien.com>
Date: Wed, 22 May 2024 17:45:29 -0400
Subject: [PATCH] Change all script strings to Rc<str>

---
 build.rs                |  5 +++--
 src/eval/environment.rs |  1 +
 src/lex.rs              | 26 ++++++++++++++------------
 src/parse.rs            | 16 ++++------------
 4 files changed, 22 insertions(+), 26 deletions(-)

diff --git a/build.rs b/build.rs
index 2f9e4e4..46ee1e4 100644
--- a/build.rs
+++ b/build.rs
@@ -22,7 +22,8 @@ fn do_ast_codegen<W: Write>(mut output: W) {
     )
     .unwrap();
 
-    define_imports(&mut output, &["crate::lex::Token"]).expect("failed to define imports");
+    define_imports(&mut output, &["crate::lex::Token", "std::rc::Rc"])
+        .expect("failed to define imports");
     writeln!(output).unwrap();
 
     define_literals(
@@ -30,7 +31,7 @@ fn do_ast_codegen<W: Write>(mut output: W) {
         "LiteralValue",
         &BTreeMap::from([
             ("Number", Some("f64")),
-            ("String", Some("String")),
+            ("String", Some("Rc<str>")),
             ("True", None),
             ("False", None),
             ("Nil", None),
diff --git a/src/eval/environment.rs b/src/eval/environment.rs
index e2f3f9e..d61d125 100644
--- a/src/eval/environment.rs
+++ b/src/eval/environment.rs
@@ -25,6 +25,7 @@ impl Environment {
     const ROOT_KEY: u32 = 0;
 
     #[must_use]
+    #[allow(dead_code)]
     pub fn new() -> Self {
         Self::default()
     }
diff --git a/src/lex.rs b/src/lex.rs
index 6f3de44..0e7fa19 100644
--- a/src/lex.rs
+++ b/src/lex.rs
@@ -1,5 +1,8 @@
 use itertools::{FoldWhile, Itertools};
-use std::iter::{self, Peekable};
+use std::{
+    iter::{self, Peekable},
+    rc::Rc,
+};
 use thiserror::Error;
 
 use crate::ScriptError;
@@ -28,8 +31,8 @@ pub enum TokenKind {
     LessEqual,
 
     // Literals
-    Identifier(String),
-    String(String),
+    Identifier(Rc<str>),
+    String(Rc<str>),
     Number(f64),
 
     // Keywords
@@ -92,10 +95,6 @@ impl Token {
         &self.kind
     }
 
-    pub fn into_kind(self) -> TokenKind {
-        self.kind
-    }
-
     pub fn lexeme(&self) -> &str {
         &self.lexeme
     }
@@ -326,16 +325,19 @@ fn lex_remaining_string_literal<I: Iterator<Item = char>>(
         .into_inner();
 
     if end_found {
+        let lexeme = format!("\"{contents}\"");
+        // must include quotes
+        let length = contents.len() + 2;
+
         Ok(Consumed {
             token: Some(Token {
-                kind: TokenKind::String(contents.clone()),
-                lexeme: format!("\"{contents}\""),
+                kind: TokenKind::String(contents.into()),
+                lexeme,
                 line: start_line + newlines,
             }),
             span: Span {
                 lines: newlines,
-                // must include the quotes
-                chars: contents.len() + 2,
+                chars: length,
             },
         })
     } else {
@@ -401,6 +403,6 @@ fn tokenize_word(word: String) -> TokenKind {
         "true" => TokenKind::True,
         "var" => TokenKind::Var,
         "while" => TokenKind::While,
-        _other => TokenKind::Identifier(word),
+        _other => TokenKind::Identifier(word.into()),
     }
 }
diff --git a/src/parse.rs b/src/parse.rs
index b1eb400..7b60011 100644
--- a/src/parse.rs
+++ b/src/parse.rs
@@ -81,7 +81,6 @@ fn parse<I: Iterator<Item = Token>, F: FnMut(ScriptError)>(
                     line: error.line.unwrap_or_default(),
                     location: String::new(),
                 });
-                todo!("{}", error.message);
             }
         }
     }
@@ -329,17 +328,10 @@ fn parse_primary<I: Iterator<Item = Token>>(iter: &mut Peekable<I>) -> Result<Ex
             value: LiteralValue::Number(*number),
             token,
         }),
-        TokenKind::String(_) => {
-            // TODO: we used to do this with into_kind, but we need to change Token to Rc<str> to fix cloning issues
-            // special case to avoid cloning
-            match token.kind() {
-                TokenKind::String(string) => Ok(Expr::Literal {
-                    value: LiteralValue::String(string.clone()),
-                    token,
-                }),
-                _ => unreachable!(),
-            }
-        }
+        TokenKind::String(value) => Ok(Expr::Literal {
+            value: LiteralValue::String(value.clone()),
+            token,
+        }),
         TokenKind::LeftParen => {
             let expr = parse_expression(iter)?;
             match_token_kind!(iter, TokenKind::RightParen)