setup files for lexer part

.gitignore

@@ -0,0 +1,3 @@
+.idea
+
+lexer.rb

README.md

@@ -1,3 +1,15 @@
 # parser
 
-parser ba
+###Prerequisites
+
+* Rexical (rex) 
+
+###Available commands
+
+* `rake lexer` - generates `lexer.rb` file based on `specification.rex` file
+
+###Testing
+
+To run only `lexer` tests, execute : `rspec spec/query_lexer_spec.rb`
+
+To run all tests, execute : `rake spec`

Rakefile

@@ -0,0 +1,12 @@
+require 'rspec/core/rake_task'
+
+RSpec::Core::RakeTask.new do |c|
+  options = ['--color']
+  options += ["--format", "documentation"]
+  c.rspec_opts = options
+end
+
+desc "Generate Lexer"
+task :lexer do
+  `rex specification.rex -o lexer.rb`
+end

spec/query_lexer_spec.rb

@@ -0,0 +1,10 @@
+require './lexer'
+
+class QueryLexerTester
+  describe 'Testing the Lexer' do
+    before do
+      @evaluator = Query.new
+    end
+
+  end
+end

specification.rex

@@ -0,0 +1,17 @@
+class Query
+macro
+
+
+rule
+    .
+
+inner
+  def tokenize(code)
+    scan_setup(code)
+    tokens = []
+    while token = next_token
+      tokens << token
+    end
+    tokens
+  end
+end