CLI: accept --log option

lib/imbecile.rb

@@ -22,10 +22,10 @@ module Imbecile
 
   class << self
 
-    def run(input_file, output_file)
+    def run(input_file, output_file, log_file)
       begin
         grammar = Grammar.new(File.read(input_file))
-        generator = Generator.new(grammar)
+        generator = Generator.new(grammar, log_file)
         generator.generate(output_file)
       rescue Error => e
         $stderr.puts e.message

lib/imbecile/cli.rb

@@ -4,6 +4,7 @@ module Imbecile
     USAGE = <<EOF
 Usage: #{$0} [options] <input-file> <output-file>
 Options:
+  --log LOG   Write log file
   --version   Show program version and exit
   -h, --help  Show this usage and exit
 EOF
@@ -11,9 +12,17 @@ EOF
     class << self
 
       def run(args)
-        extra_args = []
-        args.each do |arg|
+        params = []
+        log_file = nil
+        i = 0
+        while i < args.size
+          arg = args[i]
           case arg
+          when "--log"
+            if i + 1 < args.size
+              i += 1
+              log_file = args[i]
+            end
           when "--version"
             puts "imbecile v#{VERSION}"
             return 0
@@ -24,18 +33,19 @@ EOF
             $stderr.puts "Error: unknown option #{arg}"
             return 1
           else
-            extra_args << arg
+            params << arg
           end
+          i += 1
         end
-        if extra_args.size != 2
+        if params.size != 2
           $stderr.puts "Error: specify input and output files"
           return 1
         end
-        unless File.readable?(args[0])
-          $stderr.puts "Error: cannot read #{args[0]}"
+        unless File.readable?(params[0])
+          $stderr.puts "Error: cannot read #{params[0]}"
           return 2
         end
-        Imbecile.run(*args)
+        Imbecile.run(*params, log_file)
       end
 
     end

lib/imbecile/generator.rb

@@ -3,8 +3,9 @@ module Imbecile
   # Class to generate the parser generator source.
   class Generator
 
-    def initialize(grammar)
+    def initialize(grammar, log_file)
       @grammar = grammar
+      @log_file = log_file
     end
 
     def generate(output_file)