support scientific nations for float options

- reference: https://stackoverflow.com/questions/638565/parsing-scientific-notation-sensibly
- remove the todo comment(no idea for etc)

Signed-off-by: Hansuk <flavono123@gmail.com>

2 files changed, 20 insertions, 3 deletions

diff --git a/lib/slop/types.rb b/lib/slop/types.rb
index 07d7e62..c1055ea 100644
--- a/lib/slop/types.rb
+++ b/lib/slop/types.rb
@@ -52,8 +52,7 @@ module Slop
   # Cast the option argument to a Float.
   class FloatOption < Option
     def call(value)
-      # TODO: scientific notation, etc.
-      value =~ /\A[+-]?\d*\.*\d+\z/ && value.to_f
+      value =~ /\A[+-]?(?:0|[1-9]\d*)(?:\.\d*)?(?:[eE][+-]?\d+)?\z/ && value.to_f
     end
   end
 
diff --git a/test/types_test.rb b/test/types_test.rb
index 171c4d9..728b969 100644
--- a/test/types_test.rb
+++ b/test/types_test.rb
@@ -56,7 +56,9 @@ describe Slop::FloatOption do
     @apr_value = 2.9
     @minus = @options.float "--minus"
     @plus = @options.float "--plus"
-    @result  = @options.parse %W(--apr #{@apr_value} --minus -6.1 --plus +9.4)
+    @scientific_notation = @options.float "--scientific-notation"
+    @scientific_notation_value = 4e21
+    @result  = @options.parse %W(--apr #{@apr_value} --minus -6.1 --plus +9.4 --scientific-notation #{@scientific_notation_value})
   end
 
   it "returns the value as a float" do
@@ -65,6 +67,22 @@ describe Slop::FloatOption do
     assert_equal 9.4, @result[:plus]
   end
 
+  it "parses scientific notations" do
+    assert_equal @scientific_notation_value, @result[:scientific_notation]
+    @scientific_notation_value = 4E21
+    @result  = @options.parse %W(--scientific-notation #{@scientific_notation_value})
+    assert_equal @scientific_notation_value, @result[:scientific_notation]
+    @scientific_notation_value = 4.0e21
+    @result  = @options.parse %W(--scientific-notation #{@scientific_notation_value})
+    assert_equal @scientific_notation_value, @result[:scientific_notation]
+    @scientific_notation_value = -4e21
+    @result  = @options.parse %W(--scientific-notation #{@scientific_notation_value})
+    assert_equal @scientific_notation_value, @result[:scientific_notation]
+    @scientific_notation_value = 4e-21
+    @result  = @options.parse %W(--scientific-notation #{@scientific_notation_value})
+    assert_equal @scientific_notation_value, @result[:scientific_notation]
+  end
+
   it "returns nil for non-numbers by default" do
     @result.parser.parse %w(--apr hello)
     assert_nil @result[:apr]