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Peggi : A Parsing framework for Parsing Expression Grammar

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created by
Daniel Schemala
script type
Peggi is a parsing framework. On it's own, it's of not much use, but it can serve you when you write a Vim script that has to struggle with data too complicated to parse with regular expressions alone.

It's home is here: https://github.com/EinfachToll/peggi/

Basic Usage

1. In your Vim script, first specify the formal grammar of your data as Parsing Expression Grammar (PEG)
2. Then start Peggi: `let result = peggi#peggi#parse(grammar, data, start-nonterminal)`

See the Readme for details.


As an example, let's look at a script that uses Peggi for processing arithmetic expressions:

let s:grammar = '
            \ Expression = ( Term , /\s*[+-]/.strip() , Expression ).g:compute()  |  Term
            \ Term = ( Factor , /\s*[*\/]/.strip() , Term ).g:compute()  |  Factor
            \ Factor = ( /\s*(/ , Expression , /\s*)/ ).take("1")  |  /\s*[-0-9.]\+/.str2float()
            \ '

function! g:compute(list)
    if a:list[1] == '*'
        return a:list[0] * a:list[2]
    elseif a:list[1] == '/'
        return a:list[0] / a:list[2]
    elseif a:list[1] == '+'
        return a:list[0] + a:list[2]
    elseif a:list[1] == '-'
        return a:list[0] - a:list[2]

let s:example = '-10 * (2* 2)/(0.6 +2)'

echo peggi#peggi#parse(s:grammar, s:example, 'Expression')

The output is -15.384615
install details
Use one of the many plugin managers for Vim, or install it manually by putting the folder `peggi/` into any `autoload/` directory in your runtimepath.

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package script version date Vim version user release notes
peggi.tar.gz 1.0 2014-04-01 7.0 Daniel Schemala Initial upload
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