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grep: honor GNU buffer anchors #56

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Merged
lhecker merged 2 commits into from
Jun 5, 2026
+19 −0
Merged

grep: honor GNU buffer anchors #56

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2a5610b
grep: honor GNU buffer anchors
wondr-wclabs Jun 5, 2026
0ec43c8
grep: compact buffer anchor tests
wondr-wclabs Jun 5, 2026
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4 changes: 4 additions & 0 deletions src/matcher.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -269,6 +269,10 @@ impl CompiledPattern {
// GNU grep supports `{,n}` as an alias for `{0,n}`.
syntax.enable_behavior(SyntaxBehavior::SYNTAX_BEHAVIOR_ALLOW_INTERVAL_LOW_ABBREV);
}
if matches!(config.regex_mode, RegexMode::Basic | RegexMode::Extended) {
// GNU grep supports \` and \' as buffer anchors in BRE and ERE.
syntax.enable_operators(SyntaxOperator::SYNTAX_OPERATOR_ESC_GNU_BUF_ANCHOR);
}
if config.regex_mode == RegexMode::Perl {
// GNU grep supports `(?P<name>...)`.
// Unfortunately, the onig crate defines the OP2 flag without the
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15 changes: 15 additions & 0 deletions tests/test_grep.rs
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Expand Up @@ -85,6 +85,21 @@ fn bre_gnu_extensions() {
.stdout_only("*foo\n**foo\n");
}

#[test]
fn gnu_buffer_anchors() {
let (_s, mut c) = ucmd();
c.args(&[r"\`c\|r\'"])
.pipe_in("cat\nscat\ntar\ndog\n")
.succeeds()
.stdout_only("cat\ntar\n");

let (_s, mut c) = ucmd();
c.args(&["-E", r"\`c|r\'"])
.pipe_in("cat\nscat\ntar\ndog\n")
.succeeds()
.stdout_only("cat\ntar\n");
}
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@lhecker lhecker Jun 5, 2026

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This seems like it could be expressed in just two tests, no?

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@wondr-wclabs wondr-wclabs Jun 5, 2026 •
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Agreed. I collapsed this to two command invocations: one BRE case and one ERE case. Each pattern now covers both GNU buffer anchors in one command:

BRE: \`c\|r\'
ERE: \`c|r\'

That keeps the mode distinction explicit while avoiding four near-identical command setups. Focused validation after the change: cargo test --test test_grep gnu_buffer_anchors.


#[test]
fn ere_metacharacters() {
let cases: &[(&[&str], &str, &str)] = &[
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