Merge pull request #9 from jobready/add-decimal-component

Add decimal component and negative integers

README.md

@@ -49,9 +49,15 @@ Our DSL consists of these components:
       'alpha'
       'What is your name?'
 
-* **integer**, a sequence of 0-9. Examples:
+* **decimal**, a sequence of [+-]?[0-9]\*.[0-9]\*. Examples:
+
+      0.123
+      -45.78
+
+* **integer**, a sequence of [+-]?[0-9]\*. Examples:
 
       0
+      -654
       458457474
 
 * **attribute** reference, a sequence of [A-z\_][A-z0-9\_]\*[?]. When an attribute reference is evaluated,
@@ -66,7 +72,7 @@ Our DSL consists of these components:
       !Apple_Tree
       !what_i5_YOUR_name?
 
-* **element** is one of a **string**, **integer**, or **attribute**.
+* **element** is one of a **string**, **decimal**, **integer**, or **attribute**.
 
 * **comparison** consists of an **element**, followed by one of ==, !=, <, >, <=, >=, (the operator)
   followed by another **element**. When a comparison is evaluated, the 2 elements are compared using the operater

lib/boolean_dsl/evaluator.rb

@@ -1,3 +1,5 @@
+require 'bigdecimal'
+
 class BooleanDsl::Evaluator
   attr_reader :parser, :expression, :context
 
@@ -30,6 +32,8 @@ def evaluate(tree)
       !evaluate(tree[:negation])
     elsif tree.key?(:string)
       tree[:string]
+    elsif tree.key?(:decimal)
+      BigDecimal(tree[:decimal])
     elsif tree.key?(:integer)
       Integer(tree[:integer], 10)
     end

lib/boolean_dsl/parser.rb

@@ -4,7 +4,11 @@ class BooleanDsl::Parser < Parslet::Parser
   rule(:space?) { space.maybe }
 
   # Literals
-  rule(:integer) { match('[0-9]').repeat(1).as(:integer) >> space? }
+  rule(:decimal) do
+    (match('[+-]').maybe >> match('[0-9]').repeat(1) >> str(".") >> match('[0-9]').repeat(1)).as(:decimal) >> space?
+  end
+
+  rule(:integer) { (match('[+-]').maybe >> match('[0-9]').repeat(1)).as(:integer) >> space? }
 
   rule(:string_content) { (str("'").absent? >> any).repeat }
   rule(:string) { str("'") >> string_content.as(:string) >> str("'") >> space? }
@@ -17,7 +21,7 @@ class BooleanDsl::Parser < Parslet::Parser
   rule(:negation) { str('!') >> attribute.as(:negation) }
 
   # Elements
-  rule(:element) { negation | integer | string | attribute }
+  rule(:element) { negation | decimal | integer | string | attribute }
 
   # Booleans are rules that will evaluate to a true or false result
   rule(:boolean) { value_comparison | negation | attribute }

spec/evaluator/evaluate_spec.rb

@@ -8,12 +8,20 @@
 
   specify do
     expect(evaluator.evaluate(
-      left: { integer: '1' },
+      left: { integer: '+1' },
       comparison_operator: '==',
       right: { integer: '1' },
     )).to be_truthy
   end
 
+  specify do
+    expect(evaluator.evaluate(
+      left: { decimal: '-2.1' },
+      comparison_operator: '<',
+      right: { decimal: '+1.2' },
+    )).to be_truthy
+  end
+
   specify do
     expect(evaluator.evaluate(
       left: { integer: '1' },
@@ -43,7 +51,7 @@
       left: {
         left: { integer: '1' },
         comparison_operator: '==',
-        right: { integer: '7' },
+        right: { integer: '-1' },
       },
       boolean_operator: 'and',
       right: {

spec/parser_spec.rb

@@ -9,6 +9,16 @@
     specify { expect(parser.parse_with_debug('12')).to eq(integer: "12") }
     specify { expect(parser.parse_with_debug('0 ')).to eq(integer: "0") }
     specify { expect(parser.parse_with_debug('12   ')).to eq(integer: "12") }
+    specify { expect(parser.parse_with_debug('-12')).to eq(integer: "-12") }
+    specify { expect(parser.parse_with_debug('+12')).to eq(integer: "+12") }
+  end
+
+  context 'decimal literals' do
+    specify { expect(parser.parse_with_debug('0.00')).to eq(decimal: "0.00") }
+    specify { expect(parser.parse_with_debug('1.23')).to eq(decimal: "1.23") }
+    specify { expect(parser.parse_with_debug('1.23  ')).to eq(decimal: "1.23") }
+    specify { expect(parser.parse_with_debug('-1.23')).to eq(decimal: "-1.23") }
+    specify { expect(parser.parse_with_debug('+1.23')).to eq(decimal: "+1.23") }
   end
 
   context 'string literals' do
@@ -128,10 +138,10 @@
       end
 
       specify do
-        expect(parser.parse_with_debug('16 < 9565  ')).to eq(
-          left: { integer: "16" },
+        expect(parser.parse_with_debug('16.5 < 9565.8  ')).to eq(
+          left: { decimal: "16.5" },
           comparison_operator: "<",
-          right: { integer: "9565" }
+          right: { decimal: "9565.8" }
         )
       end