Merge pull request #10 from mrcsparker/blank_strings

Test fix for issue #9

Gemfile.lock

@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    kalc (1.1.2)
+    kalc (1.2.0)
       parslet (~> 1.7)
 
 GEM
@@ -11,20 +11,20 @@ GEM
     diff-lcs (1.2.5)
     parslet (1.7.1)
       blankslate (>= 2.0, <= 4.0)
-    rake (10.4.2)
-    rspec (3.3.0)
-      rspec-core (~> 3.3.0)
-      rspec-expectations (~> 3.3.0)
-      rspec-mocks (~> 3.3.0)
-    rspec-core (3.3.2)
-      rspec-support (~> 3.3.0)
-    rspec-expectations (3.3.1)
+    rake (11.2.2)
+    rspec (3.5.0)
+      rspec-core (~> 3.5.0)
+      rspec-expectations (~> 3.5.0)
+      rspec-mocks (~> 3.5.0)
+    rspec-core (3.5.0)
+      rspec-support (~> 3.5.0)
+    rspec-expectations (3.5.0)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.3.0)
-    rspec-mocks (3.3.2)
+      rspec-support (~> 3.5.0)
+    rspec-mocks (3.5.0)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.3.0)
-    rspec-support (3.3.0)
+      rspec-support (~> 3.5.0)
+    rspec-support (3.5.0)
 
 PLATFORMS
   java
@@ -36,4 +36,4 @@ DEPENDENCIES
   rspec
 
 BUNDLED WITH
-   1.10.6
+   1.12.5

lib/kalc/transform.rb

@@ -45,6 +45,11 @@ class Transform < Parslet::Transform
       Ast::StringValue.new(string)
     }
 
+    rule(:string => sequence(:string)) {
+      string = '' if string == nil
+      Ast::StringValue.new(string)
+    }
+
     rule(:boolean => simple(:boolean)) {
       Ast::BooleanValue.new(boolean)
     }

lib/kalc/version.rb

@@ -1,3 +1,3 @@
 module Kalc
-  VERSION = '1.1.2'
+  VERSION = '1.2.0'
 end

spec/interpreter_spec.rb

@@ -126,6 +126,14 @@
     it { expect(evaluate('ROUND(233.256,-2)')).to eq(200) }
   end
 
+  # https://github.com/mrcsparker/kalc/issues/9
+  # https://github.com/kschiess/parslet/issues/126
+  context 'empty strings' do
+    it { expect(evaluate('""')).to eq('') }
+    it { expect(evaluate('var1 := 1; var2 := 2; IF(var1=var2,"","ERROR")')).to eq('ERROR') }
+    it { expect(evaluate('var1 := 1; var2 := 1; IF(var1=var2,"","ERROR")')).to eq('') }
+  end
+
   private
   def evaluate(expression)
     g = @grammar.parse(expression)