Add shared syntax highlighting for source text fields

src/Theming/SourceSyntax.cs

@@ -0,0 +1,72 @@
+using System.Collections.Generic;
+using Cthangover.Core.UI.Theming;
+using Godot;
+
+namespace Cthangover.Mods.Interface.Theming
+{
+    /// <summary>
+    /// Shared source palettes for editable fields and read-only previews.
+    /// Each call returns a new highlighter: Godot binds it to one TextEdit and
+    /// keeps a per-document cache, so sharing a resource between editors would
+    /// mix their text. Scenario commands are supplied by the caller to keep
+    /// the UI toolkit independent of the dialog engine.
+    /// </summary>
+    public static class SourceSyntax
+    {
+        /// <summary>Colours JSON strings, numbers, punctuation and literal values, including unfinished input.</summary>
+        public static CodeHighlighter CreateJsonHighlighter()
+        {
+            var highlighter = CreateBase();
+            highlighter.AddColorRegion("\"", "\"", UiTokens.AccentBright);
+            return highlighter;
+        }
+
+        /// <summary>Colours Godot text scene/resource sections, strings, constructors, numbers and comments.</summary>
+        public static CodeHighlighter CreateTscnHighlighter()
+        {
+            var highlighter = CreateBase();
+            highlighter.FunctionColor = UiTokens.TypeTarget;
+            highlighter.AddColorRegion("\"", "\"", UiTokens.AccentBright);
+            highlighter.AddColorRegion(";", "", UiTokens.Faint, true);
+            foreach (var section in new[] { "gd_scene", "gd_resource", "ext_resource", "sub_resource", "resource", "node", "connection", "editable" })
+                highlighter.AddKeywordColor(section, UiTokens.TypeTarget);
+            return highlighter;
+        }
+
+        /// <summary>Colours scenario commands, named arguments, quoted dialogue, labels and comments.</summary>
+        public static CodeHighlighter CreateScenarioHighlighter(IEnumerable<string> commands)
+        {
+            var highlighter = CreateBase();
+            if (commands != null)
+            {
+                foreach (var command in commands)
+                    highlighter.AddKeywordColor(command, UiTokens.Info);
+            }
+            highlighter.AddKeywordColor("select", UiTokens.Info);
+            highlighter.AddKeywordColor("option", UiTokens.Info);
+            foreach (var argument in new[] {
+                "key", "first", "second", "hide_color", "wait", "speed", "hidden",
+                "sprites", "loop", "target", "quest_id", "show", "hide", "duration"
+            })
+                highlighter.AddKeywordColor(argument, UiTokens.Accent);
+            highlighter.AddColorRegion("\"", "\"", UiTokens.AccentBright);
+            highlighter.AddColorRegion("#", "", UiTokens.Faint, true);
+            highlighter.AddColorRegion(":", " ", UiTokens.TypeTarget, true);
+            return highlighter;
+        }
+
+        private static CodeHighlighter CreateBase()
+        {
+            var highlighter = new CodeHighlighter
+            {
+                NumberColor = UiTokens.Info,
+                SymbolColor = UiTokens.Muted,
+                FunctionColor = UiTokens.Body,
+                MemberVariableColor = UiTokens.Body,
+            };
+            foreach (var literal in new[] { "true", "false", "null" })
+                highlighter.AddKeywordColor(literal, UiTokens.TypeTarget);
+            return highlighter;
+        }
+    }
+}