LibWeb: Implement <step-position> as an enum

This simplifies parsing and serialization by using the generated
functions

Libraries/LibWeb/CSS/Enums.json

@@ -715,6 +715,14 @@
     "crispedges",
     "geometricprecision"
   ],
+  "step-position": [
+    "jump-start",
+    "jump-end",
+    "jump-none",
+    "jump-both",
+    "start",
+    "end"
+  ],
   "stroke-linecap": [
     "butt",
     "square",

Libraries/LibWeb/CSS/Parser/ValueParsing.cpp

@@ -2997,32 +2997,25 @@ RefPtr<StyleValue const> Parser::parse_easing_value(TokenStream<ComponentValue>&
             return nullptr;
 
         if (comma_separated_arguments.size() == 2) {
-            TokenStream identifier_stream { comma_separated_arguments[1] };
-            auto keyword_value = parse_keyword_value(identifier_stream);
-            if (!keyword_value)
+            if (comma_separated_arguments[1].size() != 1)
                 return nullptr;
-            switch (keyword_value->to_keyword()) {
-            case Keyword::JumpStart:
-                steps.position = EasingStyleValue::Steps::Position::JumpStart;
-                break;
-            case Keyword::JumpEnd:
-                steps.position = EasingStyleValue::Steps::Position::JumpEnd;
-                break;
-            case Keyword::JumpBoth:
-                steps.position = EasingStyleValue::Steps::Position::JumpBoth;
-                break;
-            case Keyword::JumpNone:
-                steps.position = EasingStyleValue::Steps::Position::JumpNone;
-                break;
-            case Keyword::Start:
-                steps.position = EasingStyleValue::Steps::Position::Start;
-                break;
-            case Keyword::End:
-                steps.position = EasingStyleValue::Steps::Position::End;
-                break;
-            default:
+
+            auto token = comma_separated_arguments[1][0];
+
+            if (!token.is(Token::Type::Ident))
                 return nullptr;
-            }
+
+            auto keyword = keyword_from_string(token.token().ident());
+
+            if (!keyword.has_value())
+                return nullptr;
+
+            auto step_position = keyword_to_step_position(keyword.value());
+
+            if (!step_position.has_value())
+                return nullptr;
+
+            steps.position = step_position.value();
         }
 
         // Perform extra validation
@@ -3030,7 +3023,7 @@ RefPtr<StyleValue const> Parser::parse_easing_value(TokenStream<ComponentValue>&
         // If the <step-position> is jump-none, the <integer> must be at least 2, or the function is invalid.
         // Otherwise, the <integer> must be at least 1, or the function is invalid.
         if (!intervals->is_calculated()) {
-            if (steps.position == EasingStyleValue::Steps::Position::JumpNone) {
+            if (steps.position == StepPosition::JumpNone) {
                 if (intervals->value() <= 1)
                     return nullptr;
             } else if (intervals->value() <= 0) {

Libraries/LibWeb/CSS/StyleValues/EasingStyleValue.cpp

@@ -50,13 +50,13 @@ EasingStyleValue::CubicBezier EasingStyleValue::CubicBezier::ease_in_out()
 
 EasingStyleValue::Steps EasingStyleValue::Steps::step_start()
 {
-    static Steps steps { 1, Steps::Position::Start };
+    static Steps steps { 1, StepPosition::Start };
     return steps;
 }
 
 EasingStyleValue::Steps EasingStyleValue::Steps::step_end()
 {
-    static Steps steps { 1, Steps::Position::End };
+    static Steps steps { 1, StepPosition::End };
     return steps;
 }
 
@@ -350,7 +350,7 @@ double EasingStyleValue::Steps::evaluate_at(double input_progress, bool before_f
     // https://www.w3.org/TR/css-easing-1/#step-easing-algo
     // 1. Calculate the current step as floor(input progress value × steps).
     auto resolved_number_of_intervals = number_of_intervals.resolved({}).value_or(1);
-    resolved_number_of_intervals = max(resolved_number_of_intervals, position == Steps::Position::JumpNone ? 2 : 1);
+    resolved_number_of_intervals = max(resolved_number_of_intervals, position == StepPosition::JumpNone ? 2 : 1);
 
     auto current_step = floor(input_progress * resolved_number_of_intervals);
 
@@ -358,7 +358,7 @@ double EasingStyleValue::Steps::evaluate_at(double input_progress, bool before_f
     //    - jump-start,
     //    - jump-both,
     //    increment current step by one.
-    if (position == Steps::Position::JumpStart || position == Steps::Position::Start || position == Steps::Position::JumpBoth)
+    if (position == StepPosition::JumpStart || position == StepPosition::Start || position == StepPosition::JumpBoth)
         current_step += 1;
 
     // 3. If both of the following conditions are true:
@@ -379,9 +379,9 @@ double EasingStyleValue::Steps::evaluate_at(double input_progress, bool before_f
     //    jump-none -> steps - 1
     //    jump-both -> steps + 1
     auto jumps = resolved_number_of_intervals;
-    if (position == Steps::Position::JumpNone) {
+    if (position == StepPosition::JumpNone) {
         jumps--;
-    } else if (position == Steps::Position::JumpBoth) {
+    } else if (position == StepPosition::JumpBoth) {
         jumps++;
     }
 
@@ -405,23 +405,14 @@ String EasingStyleValue::Steps::to_string(SerializationMode mode) const
         builder.append("steps(1)"sv);
     } else {
         auto position = [&] -> Optional<StringView> {
-            switch (this->position) {
-            case Steps::Position::JumpStart:
-                return "jump-start"sv;
-            case Steps::Position::JumpNone:
-                return "jump-none"sv;
-            case Steps::Position::JumpBoth:
-                return "jump-both"sv;
-            case Steps::Position::Start:
-                return "start"sv;
-            default:
+            if (first_is_one_of(this->position, StepPosition::JumpEnd, StepPosition::End))
                 return {};
-            }
+            return CSS::to_string(this->position);
         }();
         auto intervals = number_of_intervals;
         if (mode == SerializationMode::ResolvedValue) {
             auto resolved_value = number_of_intervals.resolved({}).value_or(1);
-            intervals = max(resolved_value, this->position == Steps::Position::JumpNone ? 2 : 1);
+            intervals = max(resolved_value, this->position == StepPosition::JumpNone ? 2 : 1);
         }
         if (position.has_value()) {
             builder.appendff("steps({}, {})", intervals.to_string(mode), position.value());

Libraries/LibWeb/CSS/StyleValues/EasingStyleValue.h

@@ -71,20 +71,11 @@ public:
     };
 
     struct Steps {
-        enum class Position {
-            JumpStart,
-            JumpEnd,
-            JumpNone,
-            JumpBoth,
-            Start,
-            End,
-        };
-
         static Steps step_start();
         static Steps step_end();
 
         IntegerOrCalculated number_of_intervals { 1 };
-        Position position { Position::End };
+        StepPosition position { StepPosition::End };
 
         bool operator==(Steps const&) const = default;