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Now I understand how Try works

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This commit is contained in:
Brandon Dyck 2024-09-02 12:48:48 -06:00
parent ffe949b97b
commit 0a1fe0821a
1 changed files with 5 additions and 0 deletions
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5
gigaparsec.go
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@ -85,6 +85,11 @@ func Choose[In, Out any](p, q Parser[In, Out]) Parser[In, Out] {
} }
} }
// Try behaves identically to p, except that if p returns an error,
// Try will pretend that no input was consumed. This allows infinite
// lookahead: Since Choose only calls another parser when the previous
// parser consumed nothing, Try will allow backing out of a complex
// parser that did partially succeeded.
func Try[In, Out any](p Parser[In, Out]) Parser[In, Out] { func Try[In, Out any](p Parser[In, Out]) Parser[In, Out] {
return func(input State[In]) (bool, Result[In, Out], error) { return func(input State[In]) (bool, Result[In, Out], error) {
consumed, reply, err := p(input) consumed, reply, err := p(input)