oxc-project__oxc/crates/oxc_regular_expression/examples/parse_literal.rs

#![expect(clippy::print_stdout)]
//! # Regular Expression Literal Parsing Example
//!
//! This example demonstrates parsing regular expression literals with various
//! patterns and flags to validate and analyze regex syntax.
//!
//! ## Usage
//!
//! ```bash
//! cargo run -p oxc_regular_expression --example parse_literal
//! ```

use oxc_allocator::Allocator;
use oxc_regular_expression::{LiteralParser, Options};

/// Test various regular expression patterns and demonstrate parsing results
fn main() {
    let allocator = Allocator::default();

    for (pattern_text, flags_text) in [
        (r"ab", ""),
        (r"abc", "i"),
        (r"abcd", "igv"),
        (r"emo👈🏻ji", "u"),
        (r"ab|c", "i"),
        (r"a|b+|c", "i"),
        (r"a{0}|b{1,2}|c{3,}", "i"),
        (r"(?=a)|(?<=b)|(?!c)|(?<!d)", "i"),
        (r"\n\cM\0\x41\.", ""),
        (r"\n\cM\0\x41\u1234\.", "u"),
        (r"\n\cM\0\x41\u{1f600}\.", "u"),
        (r"a\k<f>x\1c", "u"),
        (r"(cg)(?<n>cg)(?:g)", ""),
        (r"{3}", ""), // Error
        (r"Em🥹j", ""),
        (r"^(?=ab)\b(?!cd)(?<=ef)\B(?<!gh)$", ""),
        (r"^(?<!ab)$", ""),
        (r"a)", ""), // Error
        (r"c]", ""),
        (r"[abc]", ""),
        (r"[|\]]", ""),
        (r"[a&&b]", "v"),
        (r"[a--b]", "v"),
        (r"[a&&&]", "v"), // Error
        (r"[a---]", "v"), // Error
        (r"[^a--b--c]", "v"),
        (r"[a[b[c[d[e[f[g[h[i[j[k[l]]]]]]]]]]]]", "v"),
        (r"[\q{abc|d|e|}]", "v"),
        (r"\p{Basic_Emoji}", "v"),
        (r"\p{Basic_Emoji}", "u"), // Error
        (r"[[^\q{}]]", "v"),       // Error
        (r"(?<a>)(?<a>)", ""),     // Error
        (r"(?noname)", "v"),       // Error
        (r"[\bb]", ""),
        (r"a{2,1}", "v"), // Error
    ] {
        let parser = LiteralParser::new(
            &allocator,
            pattern_text,
            Some(flags_text),
            // +1 for added `/` in error reports
            Options { pattern_span_offset: 1, ..Options::default() },
        );
        let ret = parser.parse();

        let literal = format!("/{pattern_text}/{flags_text}");
        println!("Parse: {literal}");
        match ret {
            Ok(pattern) => {
                println!("✨ {pattern:#?}");
            }
            Err(error) => {
                println!("💥 {}", error.render_with_source_code(literal));
            }
        }
        println!();
    }
}