feat: use ere (compile-time regex compilation)

nix-js/Cargo.toml

@@ -62,6 +62,7 @@ rnix = "0.12"
 rowan = "0.15"
 
 nix-js-macros = { path = "../nix-js-macros" }
+ere = "0.2.4"
 
 [dev-dependencies]
 criterion = { version = "0.5", features = ["html_reports"] }

nix-js/src/bin/repl.rs

@@ -1,7 +1,6 @@
 use anyhow::Result;
 use nix_js::context::Context;
 use nix_js::error::Source;
-use regex::Regex;
 use rustyline::DefaultEditor;
 use rustyline::error::ReadlineError;
 
@@ -10,7 +9,7 @@ fn main() -> Result<()> {
 
     let mut rl = DefaultEditor::new()?;
     let mut context = Context::new()?;
-    let re = Regex::new(r"^\s*([a-zA-Z_][a-zA-Z0-9_'-]*)\s*=(.*)$").unwrap();
+    const RE: ere::Regex<3> = ere::compile_regex!("^[ \t]*([a-zA-Z_][a-zA-Z0-9_'-]*)[ \t]*(.*)$");
     loop {
         let readline = rl.readline("nix-js-repl> ");
         match readline {
@@ -19,18 +18,16 @@ fn main() -> Result<()> {
                     continue;
                 }
                 let _ = rl.add_history_entry(line.as_str());
-                if let Some(_caps) = re.captures(&line) {
+                if let Some([Some(_), Some(_ident), Some(_expr)]) = RE.exec(&line) {
                     eprintln!("Error: binding not implemented yet");
                     continue;
-                    /* let ident = caps.get(1).unwrap().as_str();
-                    let expr = caps.get(2).unwrap().as_str().trim();
-                    if expr.is_empty() {
-                        eprintln!("Error: missing expression after '='");
-                        continue;
-                    }
-                    if let Err(err) = context.add_binding(ident, expr) {
-                        eprintln!("Error: {}", err);
-                    } */
+                    // if expr.is_empty() {
+                    //     eprintln!("Error: missing expression after '='");
+                    //     continue;
+                    // }
+                    // if let Err(err) = context.add_binding(ident, expr) {
+                    //     eprintln!("Error: {}", err);
+                    // }
                 } else {
                     let src = Source::new_repl(line)?;
                     match context.eval_shallow(src) {

nix-js/src/value.rs

@@ -5,10 +5,8 @@ use core::ops::Deref;
 use std::borrow::Cow;
 use std::collections::BTreeMap;
 use std::ops::DerefMut;
-use std::sync::LazyLock;
 
 use derive_more::{Constructor, IsVariant, Unwrap};
-use regex::Regex;
 
 /// Represents a Nix symbol, which is used as a key in attribute sets.
 #[derive(Debug, Clone, Hash, PartialEq, Eq, PartialOrd, Ord, Constructor)]
@@ -23,10 +21,10 @@ impl<T: Into<String>> From<T> for Symbol {
 /// Formats a string slice as a Nix symbol, quoting it if necessary.
 pub fn format_symbol<'a>(sym: impl Into<Cow<'a, str>>) -> Cow<'a, str> {
     let sym = sym.into();
-    if REGEX.is_match(&sym) {
+    if Symbol::NORMAL_REGEX.test(&sym) {
         sym
     } else {
-        Cow::Owned(format!(r#""{sym}""#))
+        Cow::Owned(escape_quote_string(&sym))
     }
 }
 
@@ -40,13 +38,11 @@ impl Display for Symbol {
     }
 }
 
-static REGEX: LazyLock<Regex> = LazyLock::new(|| {
-    Regex::new(r"^[a-zA-Z_][a-zA-Z0-9_'-]*$").expect("hardcoded regex is always valid")
-});
 impl Symbol {
+    const NORMAL_REGEX: ere::Regex<1> = ere::compile_regex!("^[a-zA-Z_][a-zA-Z0-9_'-]*$");
     /// Checks if the symbol is a "normal" identifier that doesn't require quotes.
     fn normal(&self) -> bool {
-        REGEX.is_match(self)
+        Self::NORMAL_REGEX.test(self)
     }
 }