+ A few ways of making parlset parsers modular.

example/modularity.rb

@@ -0,0 +1,47 @@
+$:.unshift File.dirname(__FILE__) + "/../lib"
+
+require 'pp'
+require "parslet"
+
+# Demonstrates modular parsers, split out over many classes. Please look at
+# ip_address.rb as well.
+
+module ALanguage
+  include Parslet
+
+  # Parslet rules are really a special kind of method. Mix them into your
+  # classes!
+  rule(:a_language) { str('aaa') }
+end
+
+# Parslet parsers are parslet atoms as well. Create an instance and chain them
+# to your other rules. 
+#
+class BLanguage < Parslet::Parser
+  root :blang
+
+  rule(:blang) { str('bbb') }
+end
+
+# Parslet atoms are really Ruby values, pass them around. 
+c_language = Parslet.str('ccc')
+
+class Language < Parslet::Parser
+  def initialize(c_language)
+    @c_language = c_language
+    super()
+  end
+
+  root :root
+
+  include ALanguage
+
+  rule(:root) { str('a(') >> a_language >> str(')') >> space |
+                str('b(') >> BLanguage.new >> str(')') >> space | 
+                str('c(') >> @c_language >> str(')') >> space }
+  rule(:space) { str(' ').maybe }
+end
+
+Language.new(c_language).parse('a(aaa)')
+Language.new(c_language).parse('b(bbb)')
+Language.new(c_language).parse('c(ccc)')