https://github.com/vektah/goparsify

golang parser-combinator library
https://github.com/vektah/goparsify

ast golang lexer parse parser-combinators

Last synced: about 2 months ago
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golang parser-combinator library

• Host: GitHub
• URL: https://github.com/vektah/goparsify
• Owner: vektah
• License: mit
• Created: 2017-08-08T13:12:50.000Z (almost 7 years ago)
• Default Branch: master
• Last Pushed: 2022-10-14T01:04:55.000Z (over 1 year ago)
• Last Synced: 2024-02-04T13:12:00.123Z (5 months ago)
• Topics: ast, golang, lexer, parse, parser-combinators
• Language: Go
• Homepage:
• Size: 91.8 KB
• Stars: 71
• Watchers: 5
• Forks: 16
• Open Issues: 4
• Metadata Files:
  • Readme: readme.md

Lists

• awesome-list - goparsify - combinator library | vektah | 56 | (Go)

README

        
goparsify [![CircleCI](https://circleci.com/gh/Vektah/goparsify/tree/master.svg?style=shield)](https://circleci.com/gh/Vektah/goparsify/tree/master) [![godoc](http://b.repl.ca/v1/godoc-reference-blue.png)](https://godoc.org/github.com/Vektah/goparsify) [![Go Report Card](https://goreportcard.com/badge/github.com/vektah/goparsify)](https://goreportcard.com/report/github.com/vektah/goparsify)

=========

A parser-combinator library for building easy to test, read and maintain parsers using functional composition.

Everything should be unicode safe by default, but you can opt out of unicode whitespace for a decent ~20% performance boost.

```go

Run(parser, input, ASCIIWhitespace)

```

### benchmarks

I dont have many benchmarks set up yet, its pretty quick:

```

$ go test -benchmem -bench=. ./json

BenchmarkUnmarshalParsec-8         20000             74880 ns/op           50846 B/op       1318 allocs/op

BenchmarkUnmarshalParsify-8        30000             50631 ns/op           45055 B/op        233 allocs/op

BenchmarkUnmarshalStdlib-8         30000             46989 ns/op           14210 B/op        260 allocs/op

PASS

ok      github.com/vektah/goparsify/json        6.124s

```

Most of the remaining small allocs are from putting things in `interface{}` and are pretty unavoidable. https://www.darkcoding.net/software/go-the-price-of-interface/ is a good read.

### debugging parsers

When a parser isnt working as you intended you can build with debugging and enable logging to get a detailed log of exactly what the parser is doing.

1. First build with debug using `-tags debug`

2. enable logging by calling `EnableLogging(os.Stdout)` in your code

This works great with tests, eg in the goparsify source tree

```

adam:goparsify(master)$ go test -tags debug ./html -v

=== RUN   TestParse

html.go:48 | hello 
hello 
hello 
hello 
hello 
hello 
hello 
hello 
hello 
 found >

html.go:43 | hello 
]

html.go:24 | hello 


html.go:48 | 
 |           < found <

html.go:20 |  color="blue">w |           identifier found p

html.go:33 |  color="blue">w |           attrs {

html.go:32 |  color="blue">w |             attr {

html.go:20 | ="blue">world |               identifier found color

html.go:32 | "blue">world
worldworldworldworldworldworld found >

html.go:43 | world