[WIP] Support for nested boolean expressions in parentheses

- Added unit tests for range syntax
- Added logical expression unit tests
- parser respects parentheses during expression traversal

lib/liquid/parser.rb

@@ -60,12 +60,7 @@ module Liquid
       when :string, :number
         consume
       when :open_round
-        consume
+        consume_round_parentheses(token)
-        first = expression
-        consume(:dotdot)
-        last = expression
-        consume(:close_round)
-        "(#{first}..#{last})"
       else
         raise SyntaxError, "#{token} is not a valid expression"
       end
@@ -79,13 +74,32 @@ module Liquid
         operator = consume(:boolean_operator)
         left     = expr
         right    = expression
-
+        if look(:close_round)
-        "#{left} #{operator} #{right}"
+          "(#{left} #{operator} #{right})"
+        else
+          "#{left} #{operator} #{right}"
+        end
       else
         expr
       end
     end
 
+    def consume_round_parentheses(token)
+      consume
+      first = expression
+      dotdot_token = consume?(:dotdot)
+      if dotdot_token
+        last = expression
+        consume(:close_round)
+        "(#{first}..#{last})"
+      elsif look(:close_round)
+        consume(:close_round)
+        first
+      else
+        raise SyntaxError, "#{token} is not a valid expression"
+      end
+    end
+
     def argument
       str = +""
       # might be a keyword argument (identifier: expression)

test/unit/expression/logical_expression_test.rb

@@ -0,0 +1,219 @@
+# frozen_string_literal: true
+
+require 'test_helper'
+require 'test_boolean_helper'
+
+class LogicalExpressionTest < Minitest::Test
+  include Liquid
+
+  def setup
+    @ss = StringScanner.new("")
+    @cache = {}
+  end
+
+  def test_logical_detection
+    assert(Expression::LogicalExpression.logical?("foo and bar"))
+    assert(Expression::LogicalExpression.logical?("foo or bar"))
+    assert(Expression::LogicalExpression.logical?("true and false"))
+    assert(Expression::LogicalExpression.logical?("1 or 0"))
+
+    refute(Expression::LogicalExpression.logical?("foo"))
+    refute(Expression::LogicalExpression.logical?("1 == 1"))
+    refute(Expression::LogicalExpression.logical?("a contains b"))
+    refute(Expression::LogicalExpression.logical?("not foo"))
+  end
+
+  def test_parenthesized_logical_detection
+    assert(Expression::LogicalExpression.logical?("a and (b or c)"))
+    assert(Expression::LogicalExpression.logical?("(a or b) and c"))
+  end
+
+  def test_boolean_operator_detection
+    assert(Expression::LogicalExpression.boolean_operator?("and"))
+    assert(Expression::LogicalExpression.boolean_operator?("or"))
+
+    refute(Expression::LogicalExpression.boolean_operator?("not"))
+    refute(Expression::LogicalExpression.boolean_operator?("=="))
+    refute(Expression::LogicalExpression.boolean_operator?("contains"))
+    refute(Expression::LogicalExpression.boolean_operator?("foo"))
+  end
+
+  def test_basic_parsing
+    result = Expression::LogicalExpression.parse("true and false", @ss, @cache)
+    assert_instance_of(Condition, result)
+
+    result = Expression::LogicalExpression.parse("a or b", @ss, @cache)
+    assert_instance_of(Condition, result)
+  end
+
+  def test_parsing_with_different_expressions
+    # Test with simple variable expressions
+    result = Expression::LogicalExpression.parse("var1 and var2", @ss, @cache)
+    assert_instance_of(Condition, result)
+
+    # Test with comparison expressions
+    result = Expression::LogicalExpression.parse("a == 1 and b != 2", @ss, @cache)
+    assert_instance_of(Condition, result)
+  end
+
+  def test_parsing_complex_expressions
+    # Test with nested logical expressions
+    result = Expression::LogicalExpression.parse("a and b or c", @ss, @cache)
+    assert_instance_of(Condition, result)
+
+    result = Expression::LogicalExpression.parse("a or b and c", @ss, @cache)
+    assert_instance_of(Condition, result)
+  end
+
+  def test_parsing_parenthesized_expressions
+    result = Expression::LogicalExpression.parse("(a and b) or c", @ss, @cache)
+    assert_instance_of(Condition, result)
+
+    result = Expression::LogicalExpression.parse("a and (b or c)", @ss, @cache)
+    assert_instance_of(Condition, result)
+
+    # Test with complex expressions
+    result = Expression::LogicalExpression.parse("(a or b) and (c or d)", @ss, @cache)
+    assert_instance_of(Condition, result)
+  end
+
+  def test_evaluation_of_parsed_expressions
+    context = Liquid::Context.new(
+      "a" => true,
+      "b" => false,
+      "c" => true,
+      "d" => false,
+    )
+
+    # Test simple logical expressions
+    expr = Expression::LogicalExpression.parse("a and c", @ss, @cache)
+    assert_equal(true, expr.evaluate(context))
+
+    expr = Expression::LogicalExpression.parse("a and b", @ss, @cache)
+    assert_equal(false, expr.evaluate(context))
+
+    expr = Expression::LogicalExpression.parse("b or c", @ss, @cache)
+    assert_equal(true, expr.evaluate(context))
+
+    expr = Expression::LogicalExpression.parse("b or d", @ss, @cache)
+    assert_equal(false, expr.evaluate(context))
+  end
+
+  def test_evaluation_of_complex_expressions
+    context = Liquid::Context.new(
+      "a" => true,
+      "b" => false,
+      "c" => true,
+      "d" => false,
+    )
+
+    # Test complex logical expressions
+    expr = Expression::LogicalExpression.parse("a and b or c", @ss, @cache)
+    assert_equal(true, expr.evaluate(context))
+  end
+
+  def test_evaluation_of_parenthesized_expressions
+    context = Liquid::Context.new(
+      "a" => true,
+      "b" => false,
+      "c" => true,
+      "d" => false,
+    )
+
+    expr = Expression::LogicalExpression.parse("a and (b or d)", @ss, @cache)
+    assert_equal(false, expr.evaluate(context))
+
+    expr = Expression::LogicalExpression.parse("(a or b) and (c or d)", @ss, @cache)
+    assert_equal(true, expr.evaluate(context))
+
+    expr = Expression::LogicalExpression.parse("(a or b) and (b or d)", @ss, @cache)
+    assert_equal(false, expr.evaluate(context))
+  end
+
+  def test_precedence_rules
+    context = Liquid::Context.new(
+      "a" => true,
+      "b" => false,
+      "c" => true,
+    )
+
+    # Test precedence rules (AND has higher precedence than OR)
+    # This should be interpreted as: a and (b or c)
+    expr1 = Expression::LogicalExpression.parse("a and b or c", @ss, @cache)
+    assert_equal(true, expr1.evaluate(context))
+
+    # Change context to make the expressions evaluate differently
+    context = Liquid::Context.new(
+      "a" => false,
+      "b" => false,
+      "c" => true,
+    )
+
+    # With these values, "a and (b or c)" would be false
+    expr1 = Expression::LogicalExpression.parse("a and b or c", @ss, @cache)
+    assert_equal(false, expr1.evaluate(context))
+  end
+
+  def test_precedence_with_parentheses
+    context = Liquid::Context.new(
+      "a" => true,
+      "b" => false,
+      "c" => true,
+    )
+
+    # This should be interpreted as: (a and b) or c
+    expr2 = Expression::LogicalExpression.parse("(a and b) or c", @ss, @cache)
+    assert_equal(true, expr2.evaluate(context))
+
+    # Change context to make the expressions evaluate differently
+    context = Liquid::Context.new(
+      "a" => false,
+      "b" => false,
+      "c" => true,
+    )
+
+    # But "(a and b) or c" would be true
+    expr2 = Expression::LogicalExpression.parse("(a and b) or c", @ss, @cache)
+    assert_equal(true, expr2.evaluate(context))
+  end
+
+  def test_integration_with_if_tag
+    # Test that our expressions work properly in actual templates
+    assert_template_result("true", "{% if true and true %}true{% else %}false{% endif %}")
+    assert_template_result("false", "{% if true and false %}true{% else %}false{% endif %}")
+    assert_template_result("true", "{% if false or true %}true{% else %}false{% endif %}")
+    assert_template_result("false", "{% if false or false %}true{% else %}false{% endif %}")
+  end
+
+  def test_integration_with_parenthesized_if_tag
+    # Test with parenthesized expressions
+    assert_template_result("true", "{% if (true and false) or true %}true{% else %}false{% endif %}")
+    assert_template_result("false", "{% if true and (false or false) %}true{% else %}false{% endif %}")
+    assert_template_result("true", "{% if true and (false or true) %}true{% else %}false{% endif %}")
+  end
+
+  def test_integration_with_variables
+    # Test with variables
+    template = "{% if a and b %}true{% else %}false{% endif %}"
+    assert_template_result("true", template, { "a" => true, "b" => true })
+    assert_template_result("false", template, { "a" => true, "b" => false })
+
+    template = "{% if a or b %}true{% else %}false{% endif %}"
+    assert_template_result("true", template, { "a" => true, "b" => false })
+    assert_template_result("false", template, { "a" => false, "b" => false })
+  end
+
+  def test_integration_with_parenthesized_variables
+    # Test with parenthesized expressions
+    template = "{% if (a and b) or c %}true{% else %}false{% endif %}"
+    assert_template_result("true", template, { "a" => true, "b" => true, "c" => false })
+    assert_template_result("true", template, { "a" => false, "b" => false, "c" => true })
+    assert_template_result("false", template, { "a" => false, "b" => false, "c" => false })
+
+    template = "{% if a and (b or c) %}true{% else %}false{% endif %}"
+    assert_template_result("true", template, { "a" => true, "b" => true, "c" => false })
+    assert_template_result("true", template, { "a" => true, "b" => false, "c" => true })
+    assert_template_result("false", template, { "a" => true, "b" => false, "c" => false })
+    assert_template_result("false", template, { "a" => false, "b" => true, "c" => true })
+  end
+end

test/unit/range_unit_test.rb

@@ -0,0 +1,135 @@
+# frozen_string_literal: true
+
+require 'test_helper'
+
+class RangeUnitTest < Minitest::Test
+  include Liquid
+
+  def test_basic_range_creation
+    assert_template_result("1 2 3 4 5", "{% for i in (1..5) %}{{ i }} {% endfor %}")
+  end
+
+  def test_range_with_variables
+    assert_template_result("3 4 5", "{% assign start = 3 %}{% for i in (start..5) %}{{ i }} {% endfor %}")
+    assert_template_result("1 2 3", "{% assign end = 3 %}{% for i in (1..end) %}{{ i }} {% endfor %}")
+    assert_template_result("2 3 4", "{% assign start = 2 %}{% assign end = 4 %}{% for i in (start..end) %}{{ i }} {% endfor %}")
+  end
+
+  def test_range_with_whitespace
+    assert_template_result("1 2 3", "{% for i in ( 1 .. 3 ) %}{{ i }} {% endfor %}")
+    assert_template_result("1 2 3", "{% for i in (1 .. 3) %}{{ i }} {% endfor %}")
+  end
+
+  def test_range_with_expressions
+    assert_template_result("3 4 5", "{% assign x = 1 %}{% assign start = x | plus: 2 %}{% for i in (start..5) %}{{ i }} {% endfor %}")
+    assert_template_result("1 2 3", "{% assign x = 2 %}{% assign end = x | plus: 1 %}{% for i in (1..end) %}{{ i }} {% endfor %}")
+  end
+
+  def test_range_with_literals_in_iteration
+    assert_template_result("1 2 3 4 5", "{% for i in (1..5) %}{{ i }} {% endfor %}")
+  end
+
+  def test_range_size_and_first_last
+    assert_template_result("5", "{{ (1..5) | size }}")
+    assert_template_result("1", "{{ (1..5) | first }}")
+    assert_template_result("5", "{{ (1..5) | last }}")
+  end
+
+  def test_empty_ranges
+    assert_template_result("", "{% for i in (5..1) %}{{ i }}{% endfor %}")
+  end
+
+  def test_ranges_in_conditionals
+    assert_template_result("yes", "{% if 3 >= (1..5) %}no{% else %}yes{% endif %}")
+    assert_template_result("yes", "{% if (1..5) contains 3 %}yes{% else %}no{% endif %}")
+    assert_template_result("no", "{% if (1..5) contains 6 %}yes{% else %}no{% endif %}")
+  end
+
+  def test_range_with_negative_numbers
+    assert_template_result("-3 -2 -1 0", "{% for i in (-3..0) %}{{ i }} {% endfor %}")
+  end
+
+  def test_range_with_floats
+    # Liquid doesn't support float ranges, should either error or not iterate
+    template = "{% for i in (1.5..3.5) %}{{ i }} {% endfor %}"
+    # Floats are rounded down to the nearest integer
+    assert_template_result("1 2 3", template)
+  end
+
+  # def test_ranges_with_calculated_endpoints
+  #   assert_template_result(
+  #     "3 4 5",
+  #     "{% assign start = 1 %}{% assign end = 7 %}{% for i in (start | plus: 2 .. end | minus: 2) %}{{ i }} {% endfor %}",
+  #   )
+  # end
+
+  def test_malformed_ranges
+    # Missing start value
+    assert_raises(Liquid::SyntaxError) { Liquid::Template.parse("{% for i in (..5) %}{{ i }}{% endfor %}") }
+    # Missing end value
+    assert_raises(Liquid::SyntaxError) { Liquid::Template.parse("{% for i in (1..) %}{{ i }}{% endfor %}") }
+    # Missing both values
+    assert_raises(Liquid::SyntaxError) { Liquid::Template.parse("{% for i in (..) %}{{ i }}{% endfor %}") }
+    # Wrong syntax (no parentheses)
+    assert_raises(Liquid::SyntaxError) { Liquid::Template.parse("{% for i in 1..5 %}{{ i }}{% endfor %}") }
+    # Unbalanced parentheses
+    assert_raises(Liquid::SyntaxError) { Liquid::Template.parse("{% for i in (1..5 %}{{ i }}{% endfor %}") }
+    # Invalid characters in range
+    assert_raises(Liquid::SyntaxError) { Liquid::Template.parse("{% for i in (#..@) %}{{ i }}{% endfor %}") }
+    # Invalid range
+    assert_raises(Liquid::SyntaxError) { Liquid::Template.parse("{% assign start = 1 %}{% assign end = 7 %}{% for i in (start | plus: 2 .. end | minus: 2) %}{{ i }} {% endfor %}") }
+  end
+
+  def test_ranges_with_strings_and_variables
+    assert_template_result(
+      "3 4 5",
+      "{% assign range = (3..5) %}{% for i in range %}{{ i }} {% endfor %}",
+    )
+    assert_template_result(
+      "4 5 6",
+      "{% assign start = 4 %}{% assign range = (start..6) %}{% for i in range %}{{ i }} {% endfor %}",
+    )
+  end
+
+  def test_ranges_with_limit_and_offset
+    assert_template_result(
+      "2 3",
+      "{% for i in (1..5) limit:2 offset:1 %}{{ i }} {% endfor %}",
+    )
+    assert_template_result(
+      "3 4 5",
+      "{% for i in (1..5) offset:2 %}{{ i }} {% endfor %}",
+    )
+    assert_template_result(
+      "1 2",
+      "{% for i in (1..5) limit:2 %}{{ i }} {% endfor %}",
+    )
+  end
+
+  def test_reversed_ranges
+    assert_template_result(
+      "5 4 3 2 1",
+      "{% for i in (1..5) reversed %}{{ i }} {% endfor %}",
+    )
+  end
+
+  def test_variable_ranges_with_reversed
+    assert_template_result(
+      "4 3 2 1",
+      "{% assign num = 4 %}{% for i in (1..num) reversed %}{{ i }} {% endfor %}",
+    )
+  end
+
+  def test_assigned_ranges_with_reversed
+    assert_template_result(
+      "5 4 3 2 1",
+      "{% assign range = (1..5) %}{% for i in range reversed %}{{ i }} {% endfor %}",
+    )
+  end
+
+  private
+
+  def assert_template_result(expected, template, assigns = {})
+    assert_equal(expected, Liquid::Template.parse(template).render!(assigns).strip)
+  end
+end