Merge pull request #278 from heyvito/feat/validate-types

Add support to optional type validation

7 files changed, 121 insertions, 8 deletions

diff --git a/README.md b/README.md
index 3876428..f15fbc3 100644
--- a/README.md
+++ b/README.md
@@ -204,6 +204,8 @@ Slop will raise errors for the following:
 * An option used without an argument when it expects one: `Slop::MissingArgument`
 * An option used that Slop doesn't know about: `Slop::UnknownOption`
 * An option marked as `required` when not provided: `Slop::MissingRequiredOption`
+* An option marked as `validate_types`, with an argument that does not match its
+type (i.e. `bla` for `integer`): `Slop::InvalidOptionValue`
 
 These errors inherit from `Slop::Error`, so you can rescue them all.
 Alternatively you can suppress these errors with the `suppress_errors` config
@@ -222,6 +224,33 @@ opts = Slop.parse do
 end
 ```
 
+Validating Types
+----------------
+
+By default, Slop does not validate whether an argument is a valid value for a
+given option; instead, if the option has a default value, it will be used over
+the invalid argument provided.
+In order to have types (such as `integer` and `float`) validate and indicate
+that the provided value is invalid, an extra option can be either provided to
+the argument itself, or its option set:
+
+```ruby
+opts = Slop::Options.new
+opts.int "-p", "--port", "a port", default: 80, validate_types: true
+
+parser = Slop::Parser.new(opts)
+result = parser.parse(["--port", "bla"])
+# invalid value for -p, --port (Slop::InvalidOptionValue)
+
+# Or to the option set...
+opts = Slop::Options.new(validate_types: true)
+opts.int "-p", "--port", "a port", default: 80
+
+parser = Slop::Parser.new(opts)
+result = parser.parse(["--port", "bla"])
+# invalid value for -p, --port (Slop::InvalidOptionValue)
+```
+
 Printing help
 -------------
 
@@ -279,4 +308,4 @@ end
 Commands
 --------
 
-Slop not longer has built in support for git-style subcommands.
+Slop no longer has built in support for git-style subcommands.
diff --git a/lib/slop/error.rb b/lib/slop/error.rb
index ddfa1a7..b83cab3 100644
--- a/lib/slop/error.rb
+++ b/lib/slop/error.rb
@@ -38,4 +38,16 @@ module Slop
   # Suppress with the `suppress_errors` config option.
   class MissingRequiredOption < Error
   end
+
+  # Raised when a given option is provided by the user and does not
+  # match the expected format for that type. This is only raised if
+  # validate_types is set to true.
+  class InvalidOptionValue < Error
+    attr_reader :flag
+
+    def initialize(msg, flag)
+      super(msg)
+      @flag = flag
+    end
+  end
 end
diff --git a/lib/slop/option.rb b/lib/slop/option.rb
index 093b37f..655b283 100644
--- a/lib/slop/option.rb
+++ b/lib/slop/option.rb
@@ -56,7 +56,11 @@ module Slop
           raise Slop::MissingArgument.new("missing argument for #{flag}", flags)
         end
       else
-        @value = call(value)
+        if validate_type? && !valid?(value) && !suppress_errors?
+          raise Slop::InvalidOptionValue.new("invalid value for #{flag}", flags)
+        end
+
+        @value = valid?(value) && call(value)
       end
 
       block.call(@value) if block.respond_to?(:call)
@@ -107,6 +111,13 @@ module Slop
       config[:required]
     end
 
+    # Returns true if an exception should be raised when this option value can't
+    # be parsed into the desired type or does not conform to the expected type's
+    # format
+    def validate_type?
+      config[:validate_type] || config[:validate_types]
+    end
+
     # Returns all flags joined by a comma. Used by the help string.
     def flag
       flags.join(", ")
@@ -119,6 +130,13 @@ module Slop
       key.to_sym
     end
 
+    # Override this if you want to provide a custom validator for a type. This
+    # method must return whether the provided value is valid for the current
+    # argument's type
+    def valid?(value)
+      true
+    end
+
     # Returns true if this option should be displayed with dashes transformed into underscores.
     def underscore_flags?
       config[:underscore_flags]
diff --git a/lib/slop/options.rb b/lib/slop/options.rb
index 17e9501..5e71eac 100755
--- a/lib/slop/options.rb
+++ b/lib/slop/options.rb
@@ -7,6 +7,7 @@ module Slop
       type:             "null",
       banner:           true,
       underscore_flags: true,
+      validate_types:   false,
     }
 
     # The Array of Option instances we've created.
@@ -24,6 +25,9 @@ module Slop
     # The String banner prefixed to the help string.
     attr_accessor :banner
 
+    # Whether we should validate types of values provided by the user
+    attr_accessor :validate_types
+
     def initialize(**config, &block)
       @options    = []
       @separators = []
diff --git a/lib/slop/types.rb b/lib/slop/types.rb
index 83e4a0b..a08537d 100644
--- a/lib/slop/types.rb
+++ b/lib/slop/types.rb
@@ -22,6 +22,13 @@ module Slop
     attr_accessor :explicit_value
 
     FALSE_VALUES = [false, 'false', 'no', 'off', '0'].freeze
+    TRUE_VALUES = [true, 'true', 'yes', 'on', '1'].freeze
+    VALID_VALUES = (FALSE_VALUES + TRUE_VALUES).freeze
+
+    def valid?(value)
+      return true if value.is_a?(String) && value.start_with?("--")
+      value.nil? || VALID_VALUES.include?(value)
+    end
 
     def call(value)
       self.explicit_value = value
@@ -52,8 +59,14 @@ module Slop
 
   # Cast the option argument to an Integer.
   class IntegerOption < Option
+    INT_STRING_REGEXP = /\A[+-]?\d+\z/.freeze
+
+    def valid?(value)
+      value =~ INT_STRING_REGEXP
+    end
+
     def call(value)
-      value =~ /\A[+-]?\d+\z/ && value.to_i
+      value.to_i
     end
   end
   IntOption = IntegerOption
@@ -62,8 +75,12 @@ module Slop
   class FloatOption < Option
     FLOAT_STRING_REGEXP = /\A[+-]?(?:0|[1-9]\d*)(?:\.\d*)?(?:[eE][+-]?\d+)?\z/.freeze
 
+    def valid?(value)
+      value =~ FLOAT_STRING_REGEXP
+    end
+
     def call(value)
-      value =~ FLOAT_STRING_REGEXP && value.to_f
+      value.to_f
     end
   end
 
diff --git a/test/error_test.rb b/test/error_test.rb
index d9c71ab..8ea9069 100644
--- a/test/error_test.rb
+++ b/test/error_test.rb
@@ -63,3 +63,18 @@ describe Slop::MissingRequiredOption do
     opts.parse []
   end
 end
+
+describe Slop::InvalidOptionValue do
+  it "raises when an option has an invalid value" do
+    opts = Slop::Options.new(validate_types: true)
+    opts.integer "-n", "--number", default: 10
+    assert_raises(Slop::InvalidOptionValue) { opts.parse %w(-n foo) }
+  end
+
+  it "does not raise when errors are suppressed" do
+    opts = Slop::Options.new(suppress_errors: true)
+    opts.integer "-n", "--number", default: 10, validate_type: true
+    r = opts.parse %w(-n foo)
+    assert_equal(10, r[:n])
+  end
+end
diff --git a/test/types_test.rb b/test/types_test.rb
index ea2ba8d..c6f0864 100644
--- a/test/types_test.rb
+++ b/test/types_test.rb
@@ -31,10 +31,10 @@ end
 describe Slop::BoolOption do
   before do
     @options  = Slop::Options.new
-    @verbose  = @options.bool "--verbose"
+    @verbose  = @options.bool "--verbose", validate_type: true
     @quiet    = @options.bool "--quiet"
     @inversed = @options.bool "--inversed", default: true
-    @explicit = @options.bool "--explicit"
+    @explicit = @options.bool "--explicit", validate_type: true
     @bloc     = @options.bool("--bloc"){|val| (@bloc_val ||= []) << val}
     @result   = @options.parse %w(--verbose --no-inversed
                                   --bloc --no-bloc
@@ -60,13 +60,19 @@ describe Slop::BoolOption do
   it "returns false when explicitly false" do
     assert_equal false, @result[:explicit]
   end
+
+  it "raises with invalid types" do
+    assert_raises(Slop::InvalidOptionValue) do
+      @result.parser.parse %w(--verbose foo)
+    end
+  end
 end
 
 describe Slop::IntegerOption do
   before do
     @options = Slop::Options.new
     @age     = @options.integer "--age"
-    @minus   = @options.integer "--minus"
+    @minus   = @options.integer "--minus", validate_type: true
     @plus    = @options.integer "--plus"
     @result  = @options.parse %w(--age 20 --minus -10 --plus +30)
   end
@@ -81,6 +87,12 @@ describe Slop::IntegerOption do
     @result.parser.parse %w(--age hello)
     assert_nil @result[:age]
   end
+
+  it "raises with invalid types" do
+    assert_raises(Slop::InvalidOptionValue) do
+      @result.parser.parse %w(--minus foo)
+    end
+  end
 end
 
 describe Slop::FloatOption do
@@ -88,7 +100,7 @@ describe Slop::FloatOption do
     @options = Slop::Options.new
     @apr     = @options.float "--apr"
     @apr_value = 2.9
-    @minus = @options.float "--minus"
+    @minus = @options.float "--minus", validate_type: true
     @plus = @options.float "--plus"
     @scientific_notation = @options.float "--scientific-notation"
     @scientific_notation_value = 4e21
@@ -125,6 +137,12 @@ describe Slop::FloatOption do
     @result.parser.parse %w(--apr hello)
     assert_nil @result[:apr]
   end
+
+  it "raises with invalid types" do
+    assert_raises(Slop::InvalidOptionValue) do
+      @result.parser.parse %w(--minus foo)
+    end
+  end
 end
 
 describe Slop::ArrayOption do