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package forms
import (
"regexp"
"github.com/la5nta/pat/internal/debug"
)
// placeholderReplacer returns a function that performs a case-insensitive search and replace.
// The placeholders are expected to be encapsulated with prefix and suffix.
// Any whitespace between prefix/suffix and key is ignored.
func placeholderReplacer(prefix, suffix string, fields map[string]string) func(string) string {
const (
space = `\s*`
caseInsensitiveFlag = `(?i)`
)
// compileRegexp compiles a case insensitive regular expression matching the given key.
prefix, suffix = regexp.QuoteMeta(prefix)+space, space+regexp.QuoteMeta(suffix)
compileRegexp := func(key string) *regexp.Regexp {
return regexp.MustCompile(caseInsensitiveFlag + prefix + regexp.QuoteMeta(key) + suffix)
}
// Build a map from regexp to replacement values for all tags.
regexps := make(map[*regexp.Regexp]string, len(fields))
for key, newValue := range fields {
regexps[compileRegexp(key)] = newValue
}
// Return a function for applying the replacements.
return func(str string) string {
for re, newValue := range regexps {
str = re.ReplaceAllLiteralString(str, newValue)
}
if debug.Enabled() {
// Log remaining insertion tags
re := caseInsensitiveFlag + prefix + `[\w_-]+` + suffix
if matches := regexp.MustCompile(re).FindAllString(str, -1); len(matches) > 0 {
debug.Printf("Unhandled placeholder: %v", matches)
}
}
return str
}
}
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