[command] Add informative error example that optionally shows backtraces.

lib/motion/error.rb

@@ -0,0 +1,29 @@
+# Copyright (c) 2012, HipByte SPRL and contributors
+# All rights reserved.
+# 
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+# 
+# 1. Redistributions of source code must retain the above copyright notice, this
+#    list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright notice,
+#    this list of conditions and the following disclaimer in the documentation
+#    and/or other materials provided with the distribution.
+# 
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+# ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+module Motion
+  # This class is extended, when using the commands, with the
+  # `CLAide::InformativeError` module. This will cause these errors to only
+  # show their message when raised, unless the `--verbose` option is specified.
+  class InformativeError < StandardError; end
+end

lib/motion/project/command.rb

@@ -22,10 +22,19 @@
 # SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 require 'motion/version'
+require 'motion/error'
 
 $:.unshift File.expand_path('../../../../vendor/CLAide/lib', __FILE__)
 require 'claide'
 
+module Motion
+  # This will cause these errors to only show their message when raised, unless
+  # the `--verbose` option is specified.
+  class InformativeError
+    include CLAide::InformativeError
+  end
+end
+
 module Motion; module Project
   class Command < CLAide::Command
 
@@ -120,10 +129,6 @@ module Motion; module Project
       #end
     #end
 
-    class InformativeError < StandardError
-      include CLAide::InformativeError
-    end
-
     protected
 
     def die(message)

lib/motion/project/template.rb

@@ -21,6 +21,8 @@
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 # SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
+require 'motion/error'
+
 require 'erb'
 require 'fileutils'
 
@@ -58,19 +60,17 @@ module Motion; module Project
 
       @template_directory = self.class.all_templates[@template_name]
       unless @template_directory
-        $stderr.puts "Cannot find template `#{@template_name}' in #{Paths.join(' or ')}"
-        $stderr.puts "Available templates: " + self.class.all_templates.keys.join(', ')
-        exit 1
+        raise InformativeError, "Cannot find template `#{@template_name}' in " \
+                                "#{Paths.join(' or ')}. Available templates: " \
+                                "#{self.class.all_templates.keys.join(', ')}"
       end
 
       unless app_name.match(/^[\w\s-]+$/)
-        $stderr.puts "Invalid app name"
-        exit 1
+        raise InformativeError, "Invalid project name."
       end
 
       if File.exist?(app_name)
-        $stderr.puts "Directory `#{app_name}' already exists"
-        exit 1
+        raise InformativeError, "Directory `#{app_name}' already exists"
       end
     end