[AV-6848] Add date element

CHANGELOG.md

@@ -6,6 +6,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [1.8.0] - 2024-10-15
+### Added
+- Date element
+
 ## [1.7.0] - 2022-12-12
 ### Added
 - Array element

README.md

@@ -65,6 +65,11 @@ Our DSL consists of these components:
       43.56%
       -20%
 
+* **date**, a sequence of [0-9]{1,2}\/[0-9]{1,2}\/[0-9]{4}. Examples:
+
+      9/2/2024
+      31/12/2024
+
 * **array**, a comma separated list of integer, decimal or string elements wrapped by [] (square brackets)
 
       [1,2,3]
@@ -81,7 +86,7 @@ Our DSL consists of these components:
       !Apple_Tree
       !what_i5_YOUR_name?
 
-* **element** is one of a **string**, **percentage**, **decimal**, **integer**, **array** or **attribute**.
+* **element** is one of a **string**, **date**, **percentage**, **decimal**, **integer**, **array** or **attribute**.
 
 * **comparison** consists of an **element**, followed by one of ==, !=, <, >, <=, >=, includes, excludes (the operator)
   followed by another **element**. When a comparison is evaluated, the 2 elements are compared using the operater
@@ -92,6 +97,7 @@ Our DSL consists of these components:
       alpha != delta
       8 >= 1
       [1,2,3] includes 3
+      start_date > 1/9/2024
 
 * **boolean** expression consists of a left side, followed by one of _and_, _or_ (the operator),
   followed by a right side.

lib/boolean_dsl/evaluator.rb

@@ -26,7 +26,7 @@ def evaluate(tree)
       if context.key?(tree[:attribute].to_s)
         context[tree[:attribute].to_s]
       else
-        raise BooleanDsl::EvaluationFailed.new("Context does not have key #{tree[:attribute]}")
+        raise BooleanDsl::EvaluationFailed, "Context does not have key #{tree[:attribute]}"
       end
     elsif tree.key?(:negation)
       !evaluate(tree[:negation])
@@ -40,6 +40,12 @@ def evaluate(tree)
       BigDecimal(tree[:decimal])
     elsif tree.key?(:integer)
       Integer(tree[:integer], 10)
+    elsif tree.key?(:date)
+      begin
+        Date.parse(tree[:date])
+      rescue Date::Error => e
+        raise BooleanDsl::EvaluationFailed, "#{e.message.upcase_first} #{tree[:date]}"
+      end
     end
   end
 
@@ -68,6 +74,8 @@ def evaluate_comparison(left, operator, right)
     when 'excludes'
       !left.include?(right)
     end
+  rescue StandardError
+    raise BooleanDsl::EvaluationFailed, "Invalid comparison"
   end
 
   # Given a left and right expression and an operator, compares left and right using the operator.

lib/boolean_dsl/parser.rb

@@ -5,13 +5,16 @@ class BooleanDsl::Parser < Parslet::Parser
 
   # Literals
   rule(:sign) { match('[+-]') }
-  rule(:digits) { match('[0-9]').repeat(1) }
+  rule(:digit) { match('[0-9]') }
+  rule(:digits) { digit.repeat(1) }
   rule(:decimal_fragment) { digits >> str(".") >> digits }
 
   rule(:integer) { (sign.maybe >> digits).as(:integer) >> space? }
   rule(:decimal) { (sign.maybe >> decimal_fragment).as(:decimal) >> space? }
   rule(:percentage) { (sign.maybe >> (decimal_fragment | digits) >> str("%")).as(:percentage) >> space? }
 
+  rule(:date) { (digit.repeat(1,2) >> str("/") >> digit.repeat(1,2) >> str("/") >> digit.repeat(4,4)).as(:date) }
+
   rule(:string_content) { (str("'").absent? >> any).repeat }
   rule(:string) { str("'") >> string_content.as(:string) >> str("'") >> space? }
 
@@ -27,7 +30,7 @@ class BooleanDsl::Parser < Parslet::Parser
   rule(:negation) { str('!') >> attribute.as(:negation) }
 
   # Elements
-  rule(:element) { negation | percentage | decimal | integer | string | array | attribute }
+  rule(:element) { negation | date | percentage | decimal | integer | string | array | attribute }
 
   # Booleans are rules that will evaluate to a true or false result
   rule(:boolean) { value_comparison | negation | attribute }

spec/evaluator/evaluate_spec.rb

@@ -8,6 +8,34 @@
   specify { expect(evaluator.evaluate(percentage: '89%')).to eq(0.89) }
   specify { expect(evaluator.evaluate(string: 'alpha5')).to eq('alpha5') }
 
+  describe 'dates' do
+    subject { evaluator.evaluate(tree) }
+
+    let(:tree) { { date: date } }
+
+    context 'where date has leading zeros' do
+      let(:date) { '02/03/2024' }
+      specify { expect(subject).to eq(Date.new(2024,3,2)) }
+    end
+
+    context 'where date does not have leading zeros' do
+      let(:date) { '2/3/2024' }
+      specify { expect(subject).to eq(Date.new(2024,3,2)) }
+    end
+
+    context 'where date has mix of leading zeros' do
+      let(:date) { '2/03/2024' }
+      specify { expect(subject).to eq(Date.new(2024,3,2)) }
+    end
+
+    context 'where date is invalid' do
+      let(:date) { '32/6/2024' }
+      specify do
+        expect { subject }.to raise_error(BooleanDsl::EvaluationFailed, 'Invalid date 32/6/2024')
+      end
+    end
+  end
+
   describe 'evaluate array' do
     subject { evaluator.evaluate(tree) }
 

spec/evaluator_spec.rb

@@ -30,6 +30,17 @@
     specify { expect(evaluator.evaluate_comparison([1, 'alpha'], 'excludes', 0)).to be_truthy }
     specify { expect(evaluator.evaluate_comparison([1, 'alpha'], 'excludes', 'alpha')).to be_falsey }
     specify { expect(evaluator.evaluate_comparison([1, 'alpha'], 'excludes', 'beta')).to be_truthy }
+
+    specify { expect(evaluator.evaluate_comparison(Date.new(2024,9,1), '==', Date.new(2024,9,1))).to be_truthy }
+    specify { expect(evaluator.evaluate_comparison(Date.new(2024,9,1), '<', Date.new(2024,9,2))).to be_truthy }
+    specify { expect(evaluator.evaluate_comparison(Date.new(2024,9,1), '>', Date.new(2024,8,31))).to be_truthy }
+    specify { expect(evaluator.evaluate_comparison(Date.new(2024,9,1), '<=', Date.new(2024,9,1))).to be_truthy }
+    specify { expect(evaluator.evaluate_comparison(Date.new(2024,9,1), '>=', Date.new(2024,9,1))).to be_truthy }
+
+    specify do
+      expect { evaluator.evaluate_comparison(Date.new(2024,9,1), '>', 'a string') }
+        .to raise_error(BooleanDsl::EvaluationFailed, 'Invalid comparison')
+    end
   end
 
   context '#evaluate_boolean' do
@@ -71,6 +82,7 @@ def outcome_for(expression, context_hash = {})
     specify { expect(outcome_for("['alpha','beta'] excludes 'beta'")).to be_falsey }
     specify { expect(outcome_for("[] excludes 'beta'")).to be_truthy }
     specify { expect(outcome_for("attribute_array excludes 'beta'", { "attribute_array" => ["alpha", "beta"]})).to be_falsey }
+    specify { expect(outcome_for("start_date > 1/9/2024", { 'start_date' => Date.new(2024,9,2) })).to be_truthy }
   end
 end
 

spec/parser_spec.rb

@@ -44,6 +44,12 @@
     specify { expect(parser.parse_with_debug("'I am, 12345, \"you\" are'   ")).to eq(string: 'I am, 12345, "you" are') }
   end
 
+  context 'date literals' do
+    specify { expect(parser.parse_with_debug("31/12/2024")).to eq(date: "31/12/2024") }
+    specify { expect(parser.parse_with_debug("1/1/2024")).to eq(date: "1/1/2024") }
+    specify { expect(parser.parse_with_debug("02/03/2024")).to eq(date: "02/03/2024") }
+  end
+
   context 'arrays' do
     specify { expect(parser.parse_with_debug("[]")).to eq(array: []) }
     specify { expect(parser.parse_with_debug("[1]")).to eq(array: [{ integer: "1" }]) }