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Note: This document is rather terse, for the complete NPeg manual please refer to the README.md or the git project page at https://github.com/zevv/npeg

NPeg is a pure Nim pattern matching library. It provides macros to compile patterns and grammars (PEGs) to Nim procedures which will parse a string and collect selected parts of the input. PEGs are not unlike regular expressions, but offer more power and flexibility, and have less ambiguities.

Here is a simple example showing the power of NPeg: The macro peg compiles a grammar definition into a parser object, which is used to match a string and place the key-value pairs into the Nim table words:

Example:

import npeg

import npeg, strutils, tables

var words: Table[string, int]

let parser = peg "pairs":
  pairs <- pair * *(',' * pair) * !1
  word <- +Alpha
  number <- +Digit
  pair <- >word * '=' * >number:
    words[$1] = parseInt($2)

doAssert parser.match("one=1,two=2,three=3,four=4").ok