fix(grep): match GNU grep 3.11 output, options and POSIX regex dialects

crates/bashkit/docs/compatibility.md

@@ -70,7 +70,7 @@ for sandbox security reasons. See the compliance spec for details.
 | `eval` | `command...` | POSIX construct and execute command |
 | `readonly` | `VAR[=value]`, `-p` | POSIX mark variable read-only |
 | `times` | - | POSIX display process times |
-| `grep` | `-i`, `-v`, `-c`, `-n`, `-E`, `-q` | Pattern matching |
+| `grep` | `-G/-E/-F/-P`, `-e`, `-f`, `-i/-y`, `--no-ignore-case`, `-v`, `-w`, `-x`, `-c`, `-l`, `-L`, `-o`, `-q`, `-s`, `-m`, `-n`, `-b`, `-H/-h`, `--label`, `-T`, `-Z`, `-z`, `-a`, `-I`, `--binary-files`, `-A/-B/-C/-NUM`, `--group-separator`, `--no-group-separator`, `-r/-R`, `-d`, `-D`, `--include/--exclude/--exclude-from/--exclude-dir`; long-option prefixes | GNU grep 3.11 output; BRE/ERE leftmost-longest, back-references |
 | `rg` | `-i/-S/-s`, `-n/-N`, `--column`, `-b/--byte-offset`, `--vimgrep`, basic `--json`, `--stats`, `--null`, `-c`, `--count-matches`, `--include-zero`, `-l`, `--files-with-matches`, `--files-without-match`, `--files`, `-F`, `-w`, `-x`, `-a/--text`, `--binary`, `-m`, `-M/--max-columns`, `--max-columns-preview`, `--max-depth`, `-A`, `-B`, `-C`, separator flags, `--heading/--no-heading`, `--sort/--sortr`, `--path-separator`, `-g/--glob`, `--ignore-file`, `.ignore`/`.gitignore`, `--no-ignore*`, `--require-git/--no-require-git`, `-u/--unrestricted`, `--messages/--no-messages`, `-t/--type`, `-T/--type-not`, `--type-add`, `--type-clear`, `--type-list`, `--hidden/--no-hidden`, `-o`, `-q`, `-e`, `-f`, `-E/--encoding` (`auto`, `none`, UTF-8, UTF-16LE/BE), `-r`, `--passthru`, `--trim`, `-H/-I`, `--no-config`, `--line-buffered`, `--block-buffered`, `--mmap/--no-mmap`, `-P/--pcre2`, `--no-pcre2`, `--engine`, `--auto-hybrid-regex`, `--no-auto-hybrid-regex`, `--help`, `--version` | Recursive ripgrep-style search |
 | `sed` | `s///[gpiImMN w]`, `y`, `d`, `D`, `p`, `P`, `n`, `N`, `q[N]`, `Q[N]`, `=`, `l[N]`, `z`, `F`, `a`, `i`, `c`, `r`, `R`, `w`, `W`, `h/H/g/G/x`, `b`/`t`/`T`/`:label`, `{}`, `#`/`#n`; addresses `N`, `$`, `/re/[IM]`, `\cREc`, `first~step`, `a,b`, `a,+N`, `a,~N`, `0,/re/`, `!`; options `-n -e -f -i[SUF] -E/-r -s -z -l N -u --` and long forms | Stream editing; one stream across operands unless `-s`/`-i` |
 | `awk` (also `gawk`, `mawk`, `nawk`) | `'{print}'`, `-F`, `-v`, loops, arrays, increment, ternary | Text processing |

crates/bashkit/src/builtins/awk/mod.rs

@@ -32,7 +32,7 @@ mod io;
 mod lexer;
 mod order;
 mod parser;
-mod regex;
+pub(crate) mod regex;
 mod value;
 
 use std::future::Future;

crates/bashkit/src/builtins/awk/regex.rs

@@ -50,12 +50,22 @@ impl AwkRegex {
         let mut pat = String::with_capacity(t.pattern.len() + 8);
         pat.push_str(if icase { "(?si)" } else { "(?s)" });
         pat.push_str(&t.pattern);
+        Self::from_translated(pat, t.needs_longest)
+    }
+
+    /// Build from a pattern already in `regex` crate syntax (flags
+    /// included). Other POSIX dialects (grep's BRE/ERE) translate with
+    /// their own rules and reuse the leftmost-longest machinery here.
+    pub(crate) fn from_translated(
+        pat: String,
+        needs_longest: bool,
+    ) -> Result<AwkRegex, RegexError> {
         let re = regex::RegexBuilder::new(&pat)
             .size_limit(REGEX_SIZE_LIMIT)
             .dfa_size_limit(REGEX_DFA_SIZE_LIMIT)
             .build()
             .map_err(|e| RegexError(short_error(&e)))?;
-        let longest = if t.needs_longest {
+        let longest = if needs_longest {
             DFA::builder()
                 .configure(
                     DFA::config()