go/src/go/doc/synopsis.go

// firstSentence returns the first sentence in s.
// The sentence ends after the first period followed by space and
// not preceded by exactly one uppercase letter.
func firstSentence(s string) string { … }

// Synopsis returns a cleaned version of the first sentence in text.
//
// Deprecated: New programs should use [Package.Synopsis] instead,
// which handles links in text properly.
func Synopsis(text string) string { … }

var IllegalPrefixes …

// Synopsis returns a cleaned version of the first sentence in text.
// That sentence ends after the first period followed by space and not
// preceded by exactly one uppercase letter, or at the first paragraph break.
// The result string has no \n, \r, or \t characters and uses only single
// spaces between words. If text starts with any of the [IllegalPrefixes],
// the result is the empty string.
func (p *Package) Synopsis(text string) string { … }