= Syntax

A syntax highlighting a library for Ruby.

== About

This is a simple syntax highlighting library for Ruby. It is a naive syntax analysis tool, meaning that it does not "understand" the syntaxes of the languages it processes, but merely does some semi-intelligent pattern matching.

== Usage

There are primarily two uses for the Syntax library:

# Convert text from a supported syntax to a supported highlight format (like HTML).
# Tokenize text in a supported syntax and process the tokens directly.

=== Highlighting a supported syntax

  require 'syntax/convertors/html'

  convertor = Syntax::Convertors::HTML.for_syntax "ruby"
  puts convertor.convert( File.read( "file.rb" ) )

The above snippet will emit HTML, using spans and CSS to indicate the different highlight "groups". (Sample CSS files are included in the "data" directory.)

=== Tokenize text

  require 'syntax'

  tokenizer = Syntax.load "ruby"
  tokenizer.tokenize( File.read( "file.rb" ) ) do |token|
    puts "group(#{token.group}, #{token.instruction}) lexeme(#{token})"
  end

Tokenizing is straightforward process. Each time a new token is discovered by the tokenizer, it is yielded to the given block.

* <tt>token.group</tt> is the lexical group to which the token belongs. Each supported syntax may have it's own set of lexical groups.
* <tt>token.instruction</tt> is an instruction used to determine how this token should be treated. It will be <tt>:none</tt> for normal tokens, <tt>:region_open</tt> if the token starts a nested region, and <tt>:region_close</tt> if it closes the last opened region.
* <tt>token</tt> is itself a subclass of String, so you can use it just as you would a string. It represents the lexeme that was actually parsed.