minor changes to Masao's String patch: mirror Ruby 1.9 in that it thr…

…ows a KeyError when named interpolation placeholder is missing, rename/reformat a few things

lib/i18n/string.rb

@@ -7,23 +7,25 @@
   license terms as Ruby.
 =end
 
+class KeyError < Exception
+  def initialize(message = nil)
+    super(message || "key not found")
+  end
+end
+
 # Extension for String class. This feature is included in Ruby 1.9 or later but not occur TypeError.
 #
 # String#% method which accept "named argument". The translator can know 
 # the meaning of the msgids using "named argument" instead of %s/%d style.
 class String
+  # For older ruby versions (such as ruby-1.8.5)
+  alias :bytesize :size unless instance_methods.find {|m| m.to_s == 'bytesize'}
+  alias :interpolate_without_ruby_19_syntax :% # :nodoc:
 
-  unless instance_methods.find {|m| m.to_s == 'bytesize'} 
-    # For older ruby (such as ruby-1.8.5)
-    alias :bytesize :size
-  end
-
-  alias :_old_format_m :% # :nodoc:
-
-  PERCENT_MATCH_RE = Regexp.union(
-      /%%/,
-      /%\{(\w+)\}/,
-      /%<(\w+)>(.*?\d*\.?\d*[bBdiouxXeEfgGcps])/
+  INTERPOLATION_PATTERNS = Regexp.union(
+    /%%/,
+    /%\{(\w+)\}/,
+    /%<(\w+)>(.*?\d*\.?\d*[bBdiouxXeEfgGcps])/
   )
 
   # call-seq:
@@ -52,23 +54,19 @@ class String
   #         "%<age>d, %<weight>.1f" % {:age => 10, :weight => 43.4}
   def %(args)
     if args.kind_of?(Hash)
-      ret = dup
-      ret.gsub!(PERCENT_MATCH_RE) {|match|
+      dup.gsub(INTERPOLATION_PATTERNS) do |match|
         if match == '%%'
           '%'
-        elsif $1
-          key = $1.to_sym
-          args.has_key?(key) ? args[key] : match
-        elsif $2
-          key = $2.to_sym
-          args.has_key?(key) ? sprintf("%#{$3}", args[key]) : match
+        else
+          key = ($1 || $2).to_sym
+          raise KeyError unless args.has_key?(key)
+          $3 ? sprintf("%#{$3}", args[key]) : args[key]
         end
-      }
-      ret
+      end
     else
       ret = gsub(/%([{<])/, '%%\1')
       begin
-        ret._old_format_m(args)
+        ret.send :'interpolate_without_ruby_19_syntax', args
       rescue ArgumentError => e
         if $DEBUG
           $stderr.puts "  The string:#{ret}"

test/string_test.rb

@@ -0,0 +1,50 @@
+require File.expand_path(File.dirname(__FILE__) + '/test_helper')
+
+# thanks to Masao's String extensions these should work the same in
+# Ruby 1.8 (patched) and Ruby 1.9 (native)
+
+class I18nStringTest < Test::Unit::TestCase
+  define_method :"test: String interpolates a single argument" do
+    assert_equal "Masao", "%s" % "Masao"
+  end
+
+  define_method :"test: String interpolates an array argument" do
+    assert_equal "Masao Mutoh", "%s %s" % %w(Masao Mutoh)
+  end
+
+  define_method :"test: String interpolates a hash argument w/ named placeholders" do
+    assert_equal "Masao Mutoh", "%{first} %{last}" % { :first => 'Masao', :last => 'Mutoh' }
+  end
+
+  define_method :"test: String interpolates named placeholders with sprintf syntax" do
+    assert_equal "10, 43.4", "%<integer>d, %<float>.1f" % {:integer => 10, :float => 43.4}
+  end
+
+  define_method :"test: String interpolation raises an ArgumentError when the string has extra placeholders (Array)" do
+    assert_raises(ArgumentError) do # Ruby 1.9 msg: "too few arguments"
+      "%s %s" % %w(Masao) 
+    end
+  end
+
+  define_method :"test: String interpolation raises a KeyError when the string has extra placeholders (Hash)" do
+    assert_raises(KeyError) do # Ruby 1.9 msg: "key not found"
+      "%{first} %{last}" % { :first => 'Masao' }
+    end
+  end
+
+  define_method :"test: String interpolation does not raise when passed extra values (Array)" do
+    assert_nothing_raised do 
+      assert_equal "Masao", "%s" % %w(Masao Mutoh)
+    end
+  end
+
+  define_method :"test: String interpolation does not raise when passed extra values (Hash)" do
+    assert_nothing_raised do
+      assert_equal "Masao Mutoh", "%{first} %{last}" % { :first => 'Masao', :last => 'Mutoh', :salutation => 'Mr.' }
+    end
+  end
+
+  define_method :"test: % acts as escape character in String interpolation" do
+    assert_equal "%{first}", "%%{first}" % { :first => 'Masao' }
+  end
+end