koi-reference-parser¶ ↑

This is the reference parser implementation for the programming language Koi. The parser is implemented using a Parsing Expression Grammar (PEG) that is run by a PEG engine called Treetop.

Example¶ ↑

The parser takes a text string containing a program like:

test = 1 + 2

And turns it into an Abstract Syntax Tree (AST) that unambiguously represents the program’s structure and meaning. The AST is represented as a series of Ruby objects that subclass a generic SyntaxNode class. The code above transformed into AST would look like:

<Block "test = 1 + 2">
  <Statement "test = 1 + 2">
    <Assignment "test = 1 + 2">
      <Identifier "test">
      <AssignmentOperator "=">
      <Expression "1 + 2">
        <AdditiveExpression "1 + 2">
          <IntegerLiteral "1">
          <AdditionOperator "+">
          <IntegerLiteral "2">

The AST is also available in a far more portable format based on nested hashes by calling the to_hash method on the root AST node.

Installation¶ ↑

This parser is normally installed as part of Koi’s default toolchain. However if you would like to install it on it’s own you can do so by installing the gem like so:

gem install koi-reference-parser

Usage¶ ↑

require 'rubygems'
require 'koi-reference-parser'

include KoiReferenceParser

ast = Parser.parse( program_text )

# Get the AST as a portable nested hash
ast_hash = ast.to_hash

Author & Credits¶ ↑

Author: Aaron Gough