Ragel

Ragel is an open source programming language created in 2007.

Source code:

git clone https://github.com/bnoordhuis/ragel

#454on PLDB

17Years Old

66Repos

Ragel is a finite-state machine compiler and a parser generator. Initially Ragel supported output for C, C++ and Assembly source code,. Although subsequently extended to support several other languages (said to be Objective C, D, Go, Ruby, and Java) this support of other languages was withdrawn . Read more on Wikipedia...

Ragel website
Ragel Wikipedia page
Ragel is developed on GitHub and has 152 stars
There are at least 66 Ragel repos on GitHub
Ragel first developed in https://github.com/bnoordhuis/ragel/issues
file extensions for Ragel include rl
The Google BigQuery Public Dataset GitHub snapshot shows 295 users using Ragel in 317 repos on GitHub
Pygments supports syntax highlighting for Ragel
See also: (9 related languages)C, D, Go, Ruby, Java, Regular Expressions, ASCII, XUML, Umple

Example from the web:

=begin
%%{
  machine simple_scanner;

  action Emit {
    emit data[(ts+8)..(te-7)].pack('c*')
  }

  foo = 'STARTFOO' any+ :>> 'ENDFOO';
  
  main := |*
    foo => Emit;
    any;
  *|;
}%%
=end


# Scans a file for "STARTFOO[...]ENDFOO" blocks and outputs their contents.
#
# ENV['CHUNK_SIZE'] determines how much of the file to read in at a time, allowing you to control memory usage.
#
# Uses ragel's scanner functionality even though it's not strictly necessary.
class SimpleScanner
  attr_reader :path

  def initialize(path)
    @path = path
    %% write data;
    # % (this fixes syntax highlighting)
  end

  def emit(foo)
    $stdout.puts foo
  end
  
  def perform
    # So that ragel doesn't try to get it from data.length
    pe = :ignored
    eof = :ignored

    %% write init;
    # % (this fixes syntax highlighting)

    leftover = []
    
    File.open(path) do |f|
      while chunk = f.read(ENV['CHUNK_SIZE'].to_i)
        data = leftover + chunk.unpack('c*')
        p ||= 0
        pe = data.length

        %% write exec;
        # % (this fixes syntax highlighting)
        if ts
          leftover = data[ts..pe]
          p = p - ts
          ts = 0
        else
          leftover = []
          p = 0
        end
      end
    end
  end
end

s = SimpleScanner.new ARGV[0]
s.perform

Feature	Supported	Token	Example
Integers	✓		# [+-]?[0-9]+
Hexadecimals	✓		# 0x[0-9A-Fa-f]+
Comments	✓		# A comment
Line Comments	✓	#	# A comment
Semantic Indentation	X

Ragel - Programming language

Language features