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| -rw-r--r-- | readme.md | 13 |
1 files changed, 4 insertions, 9 deletions
@@ -1,10 +1,9 @@ -goparsify [](https://circleci.com/gh/Vektah/goparsify/tree/master) [](https://godoc.org/github.com/Vektah/goparsify) +goparsify [](https://circleci.com/gh/Vektah/goparsify/tree/master) [](https://godoc.org/github.com/Vektah/goparsify) ========= A parser-combinator library for building easy to test, read and maintain parsers using functional composition. ### todo - - godoc: I've been slack and the interfaces have been changing rapidly. - fatal errors: Some way for a parser to say "Ive found a good match, the input is broken, stop here with an error" - better errors: currently only the longest error is returned, but it would be nice to show all expected tokens that could follow. @@ -76,18 +75,14 @@ var number = Map(NumberLit(), func(n Node) Node { }) func Calc(input string) (float64, error) { - result, remaining, err := ParseString(number, input) - + result, err := Run(y, input) if err != nil { return 0, err } - if remaining != "" { - return result.(float64), errors.New("left unparsed: " + remaining) - } - return result.(float64), nil } + ``` This parser will return numbers either as float64 or int depending on the literal, for this calculator we only want floats so we Map the results and type cast. @@ -121,7 +116,7 @@ sum = Map(Seq(number, Some(And(sumOp, number))), func(n Node) Node { return Node{Result: i} }) -// and update Calc to point to the new root parser -> `result, remaining, err := ParseString(sum, input)` +// and update Calc to point to the new root parser -> `result, err := ParseString(sum, input)` ``` This parser will match number ([+-] number)+, then map its to be the sum. See how the Child map directly to the positions in the parsers? n is the result of the and, `n.Child[0]` is its first argument, `n.Child[1]` is the result of the Some parser, `n.Child[1].Child[0]` is the result of the first And and so fourth. Given how closely tied the parser and the Map are it is good to keep the two together. |