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From: Christian Surlykke on 20 Mar 2010 14:38
[Note: parts of this message were removed to make it a legal post.]

Kanocc (Kanocc Ain't NO Compiler-Compiler) 0.2.0 is released.

(Actually it was released a few months ago, but it only recently occurred to
me that I could/should announce i here. Sorry...)

What is it: Kanocc is a syntax recognition framework for Ruby. It emphasizes
seamless integration with Ruby, utilizing Ruby's flexible syntax.

Kanocc is available as a gem.

Visit http://kanocc.rubyforge.org to find documentation and downloads.


To get a little taste of Kanocc, here's an example: An interpreter for
simple arithmetic expressions could be done like this:

require "rubygems"
require "kanocc"

class Number < Kanocc::Token
attr_reader :val
pattern(/\d+/) { @val = @m[0].to_i}
end

class Expr < Kanocc::Nonterminal
attr_reader :val

rule(Expr, "+", Expr) { @val = @rhs[0].val + @rhs[2].val}
rule(Expr, "-", Expr) { @val = @rhs[0].val - @rhs[2].val}
rule(Expr, "*", Expr) { @val = @rhs[0].val * @rhs[2].val}; precedence -1
rule(Expr, "/", Expr) { @val = @rhs[0].val / @rhs[2].val}; precedence -1
rule("(", Expr, ")") { @val = @rhs[1].val}
rule(Number) {@val = @rhs[0].val}
end

myParser = Kanocc::Kanocc.new(Expr)

puts myParser.parse('3 + 4 - 2').val
puts myParser.parse('8 - 2 * 3').val
puts myParser.parse('8 - (4 - 2)').val


If this doesn't make any sense at all, you may have to read the
documentation :-)

Feedback is most welcome.


br. Christian Surlykke.

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