feat(regexlexer): compile in RE2 compatibility mode

scop · alecthomas · commit b5d03c0079f6 · 2021-05-17T14:09:19.000+10:00
To better match vanilla Go regexps and support some additional constructs that might be present in Pygments rules. https://github.com/dlclark/regexp2#re2-compatibility-mode
diff --git a/regexp.go b/regexp.go
@@ -404,7 +404,7 @@ func (r *RegexLexer) maybeCompile() (err error) {
 					pattern = "(?" + rule.flags + ")" + pattern
 				}
 				pattern = `\G` + pattern
-				rule.Regexp, err = regexp2.Compile(pattern, 0)
+				rule.Regexp, err = regexp2.Compile(pattern, regexp2.RE2)
 				if err != nil {
 					return fmt.Errorf("failed to compile rule %s.%d: %s", state, i, err)
 				}

Original file line number	Diff line number	Diff line change
`@@ -404,7 +404,7 @@ func (r *RegexLexer) maybeCompile() (err error) {`
`404`	`404`	`pattern = "(?" + rule.flags + ")" + pattern`
`405`	`405`	`}`
`406`	`406`	pattern = `\G` + pattern
`407`		`- rule.Regexp, err = regexp2.Compile(pattern, 0)`
	`407`	`+ rule.Regexp, err = regexp2.Compile(pattern, regexp2.RE2)`
`408`	`408`	`if err != nil {`
`409`	`409`	`return fmt.Errorf("failed to compile rule %s.%d: %s", state, i, err)`
`410`	`410`	`}`