https://github.com/lalloni/seared

Lightweight PEG-based text parsing in Golang without code generation.
https://github.com/lalloni/seared

go golang parser parser-library parsing parsing-expression-grammar peg text

Last synced: 4 days ago
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Lightweight PEG-based text parsing in Golang without code generation.

• Host: GitHub
• URL: https://github.com/lalloni/seared
• Owner: lalloni
• License: bsd-2-clause
• Created: 2017-02-14T22:42:18.000Z (over 7 years ago)
• Default Branch: master
• Last Pushed: 2017-03-21T11:00:21.000Z (over 7 years ago)
• Last Synced: 2024-06-21T19:54:14.761Z (5 months ago)
• Topics: go, golang, parser, parser-library, parsing, parsing-expression-grammar, peg, text
• Language: Go
• Size: 43 KB
• Stars: 4
• Watchers: 5
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
Seared

======

*Seared* is a Go library targeted at allowing easy implementation of text parsers based on powerful [Parsing Expression Grammars](https://en.wikipedia.org/wiki/Parsing_expression_grammar) without the hassle of parser generation steps, while trying to be easy to use, lightweight and appropriate for high-performance parsing needs.

So, how does a grammar definition look in practice? The well-known example "calculator" grammar can be defined like this:

```go

func Number(r *seared.Rules) seared.Rule {

    return r.Rule(func() seared.Rule {

        return r.OneOrMore(r.Range('0', '9'))

    })

}

func Factor(r *seared.Rules) seared.Rule {

    return r.Rule(func() seared.Rule {

        return r.Choice(Number(r), r.Sequence(r.Rune('('), Sum(r), r.Rune(')')))

    })

}

func Term(r *seared.Rules) seared.Rule {

    return r.Rule(func() seared.Rule {

        return r.Sequence(Factor(r), r.ZeroOrMore(r.Any("*/"), Factor(r)))

    })

}

func Sum(r *seared.Rules) seared.Rule {

    return r.Rule(func() seared.Rule {

        return r.Sequence(Term(r), r.ZeroOrMore(r.Any("+-"), Term(r)))

    })

}

func Operation(r *seared.Rules) seared.Rule {

    return r.Rule(func() seared.Rule {

        return r.Sequence(Sum(r), r.End())

    })

}

func Calculator() *seared.Parser {

    return seared.NewParser(Operation)

}

```

And this is how that parser could be directly used for syntax recognizing:

```go

parser := Calculator()

success := parser.Recognize("2+1*3+4*(2-1)")

```

License

=======

*Seared* is released under the [Simplified BSD License](./LICENSE) which can be found at the root of this project.