From 133d2e18277e32b21fb0a3c20588e546e68f5001 Mon Sep 17 00:00:00 2001
From: J Smith <dark.panda@gmail.com>
Date: Fri, 16 Apr 2021 14:36:29 -0300
Subject: [PATCH] Allow CSS functions to be used when expanding dimensions
 shorthand

---
 CHANGELOG.md                              |  2 +-
 lib/css_parser/regexps.rb                 | 16 ++++++++++++++++
 lib/css_parser/rule_set.rb                |  8 +++++++-
 test/test_rule_set_expanding_shorthand.rb | 12 ++++++++++++
 4 files changed, 36 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index de60100..be37493 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,7 +2,7 @@
 
 ### Unreleased
 
- * Put diff here
+ * Allow CSS functions to be used in CssParser::RuleSet#expand_dimensions_shorthand! [#126](https://github.com/premailer/css_parser/pull/126)
 
 ### Version 1.9.0
 
diff --git a/lib/css_parser/regexps.rb b/lib/css_parser/regexps.rb
index 9b3bcf6..a76ffda 100644
--- a/lib/css_parser/regexps.rb
+++ b/lib/css_parser/regexps.rb
@@ -58,6 +58,22 @@ def self.regex_possible_values(*values)
   RE_BORDER_STYLE = /(\s*^)?(none|hidden|dotted|dashed|solid|double|dot-dash|dot-dot-dash|wave|groove|ridge|inset|outset)(\s*$)?/imx.freeze
   RE_BORDER_UNITS = Regexp.union(BOX_MODEL_UNITS_RX, /(thin|medium|thick)/i)
 
+  # Functions like calc, var, clamp, etc.
+  RE_FUNCTIONS = /
+    (
+      [a-z0-9-]+        # function name
+    )
+    (?>
+      \(                # opening parenthesis
+        (?:
+          ([^()]+)
+          |             # recursion via subexpression
+          \g<0>
+        )*
+      \)                # closing parenthesis
+    )
+  /imx.freeze
+
   # Patterns for specificity calculations
   NON_ID_ATTRIBUTES_AND_PSEUDO_CLASSES_RX_NC = /
     (?:\.\w+)                     # classes
diff --git a/lib/css_parser/rule_set.rb b/lib/css_parser/rule_set.rb
index 793e80f..dcd6126 100644
--- a/lib/css_parser/rule_set.rb
+++ b/lib/css_parser/rule_set.rb
@@ -24,6 +24,8 @@ class RuleSet
       ['border-width', %w[border-top-width border-right-width border-bottom-width border-left-width]]
     ].freeze
 
+    WHITESPACE_REPLACEMENT = '___SPACE___'
+
     class Declarations
       class Value
         attr_reader :value
@@ -357,6 +359,7 @@ def expand_dimensions_shorthand! # :nodoc:
         #
         # TODO: rgba, hsl, hsla
         value.gsub!(RE_COLOUR) { |c| c.gsub(/(\s*,\s*)/, ',') }
+        value.gsub!(RE_FUNCTIONS) { |c| c.gsub(/\s+/, WHITESPACE_REPLACEMENT) }
 
         matches = value.strip.split(/\s+/)
 
@@ -375,7 +378,10 @@ def expand_dimensions_shorthand! # :nodoc:
         end
 
         t, r, b, l = values
-        replacement = {top => t, right => r, bottom => b, left => l}
+
+        replacement = {top => t, right => r, bottom => b, left => l}.each_with_object({}) do |(key, replacement_value), memo|
+          memo[key] = replacement_value.gsub(WHITESPACE_REPLACEMENT, ' ')
+        end
 
         declarations.replace_declaration!(property, replacement, preserve_importance: true)
       end
diff --git a/test/test_rule_set_expanding_shorthand.rb b/test/test_rule_set_expanding_shorthand.rb
index 2d41018..7caee4b 100644
--- a/test/test_rule_set_expanding_shorthand.rb
+++ b/test/test_rule_set_expanding_shorthand.rb
@@ -296,6 +296,18 @@ def test_expanding_important_shorthand_with_replaced_properties
     assert_equal expected_declarations, declarations
   end
 
+  def test_functions
+    shorthand = 'margin: calc(1em / 4 * var(--foo)); margin-left: auto; margin-right: auto;'
+    declarations = expand_declarations(shorthand)
+    expected_declarations = {
+      'margin-top' => 'calc(1em / 4 * var(--foo))',
+      'margin-bottom' => 'calc(1em / 4 * var(--foo))',
+      'margin-left' => 'auto',
+      'margin-right' => 'auto'
+    }
+    assert_equal expected_declarations, declarations
+  end
+
 protected
 
   def expand_declarations(declarations)