feat(plugin): highlight supported keywords and directives

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

5 files changed, 118 insertions, 6 deletions

diff --git a/plugin/AGENTS/ARCH.md b/plugin/AGENTS/ARCH.md
index a8986d1..31c5974 100644
--- a/plugin/AGENTS/ARCH.md
+++ b/plugin/AGENTS/ARCH.md
@@ -97,10 +97,12 @@ only a subset of its syntax:
 - Highlighted builtins: LENGTH, MID, RIGHT, LEFT, LCASE, UCASE, ASC, CHR, IS_NUM,
   NUM_TO_STR, STR_TO_NUM and EOF. The compiler's complete table is in
   `lib/CodeGen/Builtins.h` and also includes MALLOC, FREE and REALLOC.
-- CASE, CLASS, CONSTANT, OVERLOAD/OPERATOR and #LIB are supported by the compiler
-  but lack corresponding plugin language rules. SET, DATE and random-file
-  operations remain unsupported by the compiler too. Extending editor support
-  requires an explicit scope change.
+- Highlighting covers CASE/ENDCASE/OTHERWISE, CLASS/ENDCLASS/PUBLIC/PRIVATE,
+  CONSTANT, TEMPLATE, OVERLOAD/OPERATOR, EXTERN declarations, INCLUDE_OBJ, #LIB
+  and ellipses using C++ scopes. OVERLOAD borrows a declaration modifier, #LIB
+  borrows #pragma and INCLUDE_OBJ borrows #include. #LIB must occupy its own line.
+  These rules do not add indentation support for the corresponding constructs.
+  SET, DATE and random-file operations remain unsupported by the compiler.
 
 Language defaults use real Tabs, display width 4, disabled indentation detection,
 full automatic indentation, on-type formatting and native bracket pair colors.
diff --git a/plugin/ThirdPartyNotices.md b/plugin/ThirdPartyNotices.md
index 72c3190..581724f 100644
--- a/plugin/ThirdPartyNotices.md
+++ b/plugin/ThirdPartyNotices.md
@@ -3,7 +3,10 @@
 Language configuration and comment/string grammar structures are adapted from
 Microsoft VS Code’s built-in C++ extension. Exception keywords reuse its
 `keyword.control.try.cpp`, `keyword.control.catch.cpp` and
-`keyword.control.throw.cpp` scopes; ENDTRY uses the TRY scope.
+`keyword.control.throw.cpp` scopes; ENDTRY uses the TRY scope. Selection, class,
+access, constant, template, operator and external-declaration highlighting also
+reuse C++ scopes. OVERLOAD borrows a declaration modifier, #LIB borrows #pragma
+and INCLUDE_OBJ borrows #include; ellipses use the C++ variadic scope.
 
 https://github.com/microsoft/vscode/tree/main/extensions/cpp
 
diff --git a/plugin/examples/highlighting.cps b/plugin/examples/highlighting.cps
index 7b30bb7..b5deaee 100644
--- a/plugin/examples/highlighting.cps
+++ b/plugin/examples/highlighting.cps
@@ -6,6 +6,8 @@ TYPE Student
 	DECLARE Initial : CHAR
 ENDTYPE
 
+CONSTANT Limit = 3
+
 DECLARE Values : ARRAY[1:3] OF INTEGER
 DECLARE Index : INTEGER
 DECLARE Total : REAL
@@ -45,3 +47,9 @@ TRY
 CATCH
 	OUTPUT "Caught an exception"
 ENDTRY
+
+CASE OF Index
+	1 : OUTPUT "First"
+	2 TO Limit : OUTPUT "In range"
+	OTHERWISE : OUTPUT "Other"
+ENDCASE
diff --git a/plugin/syntaxes/cie-pseudocode.tmLanguage.json b/plugin/syntaxes/cie-pseudocode.tmLanguage.json
index 0ae08cc..d0830a8 100644
--- a/plugin/syntaxes/cie-pseudocode.tmLanguage.json
+++ b/plugin/syntaxes/cie-pseudocode.tmLanguage.json
@@ -9,6 +9,69 @@
       "include": "#strings"
     },
     {
+      "match": "^\\s*(#)(LIB)\\s*$",
+      "captures": {
+        "1": {
+          "name": "punctuation.definition.directive.cpp"
+        },
+        "2": {
+          "name": "keyword.control.directive.pragma.cpp"
+        }
+      }
+    },
+    {
+      "match": "(?<!\\w)(?:CASE|ENDCASE)(?!\\w)",
+      "name": "keyword.control.switch.cpp"
+    },
+    {
+      "match": "(?<!\\w)(?:OTHERWISE)(?!\\w)",
+      "name": "keyword.control.default.cpp"
+    },
+    {
+      "match": "(?<!\\w)(?:CONSTANT)(?!\\w)",
+      "name": "storage.modifier.const.cpp"
+    },
+    {
+      "match": "(?<!\\w)(?:CLASS|ENDCLASS)(?!\\w)",
+      "name": "storage.type.class.cpp"
+    },
+    {
+      "match": "(?<!\\w)(?:PUBLIC)(?!\\w)",
+      "name": "storage.type.modifier.access.control.public.cpp"
+    },
+    {
+      "match": "(?<!\\w)(?:PRIVATE)(?!\\w)",
+      "name": "storage.type.modifier.access.control.private.cpp"
+    },
+    {
+      "match": "(?<!\\w)(?:TEMPLATE)(?!\\w)",
+      "name": "storage.type.template.cpp"
+    },
+    {
+      "match": "(?<!\\w)(?:OPERATOR)(?!\\w)",
+      "name": "keyword.other.operator.overload.cpp"
+    },
+    {
+      "match": "(?<!\\w)(?:OVERLOAD)(?!\\w)",
+      "name": "storage.modifier.cpp"
+    },
+    {
+      "match": "(?<!\\w)(?:EXTERN)(?!\\w)",
+      "name": "storage.modifier.specifier.extern.cpp"
+    },
+    {
+      "match": "(?<!\\w)(?:EXTERN_FUNCTION|EXTERN_PROCEDURE)(?!\\w)",
+      "name": "storage.modifier.cpp"
+    },
+    {
+      "match": "(?<!\\w)(?:INCLUDE_OBJ)(?!\\w)",
+      "name": "keyword.control.directive.include.cpp"
+    },
+    {
+      "match": "\\.\\.\\.",
+      "name": "punctuation.vararg-ellipses.cpp"
+    },
+    {
       "match": "(?<!\\w)(?:TRY|ENDTRY)(?!\\w)",
       "name": "keyword.control.try.cpp"
     },
diff --git a/plugin/test/highlighting.test.js b/plugin/test/highlighting.test.js
index f7a67db..bfdf0a2 100644
--- a/plugin/test/highlighting.test.js
+++ b/plugin/test/highlighting.test.js
@@ -58,6 +58,42 @@ test('both assignment characters share the C++ assignment scope', () => {
 	assert.ok(!scopesAt('X - 1', '-').includes('keyword.operator.assignment.cpp'));
 });
 
+test('supported keywords reuse C++ scopes without matching identifiers or quoted text', () => {
+	for (const [words, scope] of [
+		[['CASE', 'ENDCASE'], 'keyword.control.switch.cpp'],
+		[['OTHERWISE'], 'keyword.control.default.cpp'],
+		[['CONSTANT'], 'storage.modifier.const.cpp'],
+		[['CLASS', 'ENDCLASS'], 'storage.type.class.cpp'],
+		[['PUBLIC'], 'storage.type.modifier.access.control.public.cpp'],
+		[['PRIVATE'], 'storage.type.modifier.access.control.private.cpp'],
+		[['TEMPLATE'], 'storage.type.template.cpp'],
+		[['OPERATOR'], 'keyword.other.operator.overload.cpp'],
+		[['OVERLOAD', 'EXTERN_FUNCTION', 'EXTERN_PROCEDURE'], 'storage.modifier.cpp'],
+		[['EXTERN'], 'storage.modifier.specifier.extern.cpp'],
+		[['INCLUDE_OBJ'], 'keyword.control.directive.include.cpp']
+	]) for (const word of words) {
+		assert.ok(scopesAt(word, word).includes(scope), word);
+		for (const text of [word.toLowerCase(), `${word}Value`, `_${word}`, `${word}_1`]) {
+			assert.ok(!scopesAt(text, text).includes(scope), text);
+		}
+		assert.ok(scopesAt(`// ${word}`, word).some(s => s.startsWith('comment.')));
+		assert.ok(scopesAt(`OUTPUT "${word}"`, word).some(s => s.startsWith('string.')));
+	}
+});
+
+test('library directives require their own line and ellipses use the C++ variadic scope', () => {
+	assert.ok(scopesAt('\t#LIB  ', '#').includes('punctuation.definition.directive.cpp'));
+	assert.ok(scopesAt('\t#LIB  ', 'LIB').includes('keyword.control.directive.pragma.cpp'));
+	for (const text of ['#lib', '#LIBRARY', '#LIB // comment', 'X #LIB', '// #LIB', 'OUTPUT "#LIB"']) {
+		assert.ok(!scopesAt(text, '#')
+			.includes('punctuation.definition.directive.cpp'), text);
+	}
+	for (const text of ['TEMPLATE <Types...>', 'EXTERN "C" EXTERN_PROCEDURE print(C_INT, ...)', 'CALL print(Values...)']) {
+		assert.ok(scopesAt(text, '...').includes('punctuation.vararg-ellipses.cpp'), text);
+	}
+	assert.ok(!scopesAt('Value.Field', '.').includes('punctuation.vararg-ellipses.cpp'));
+});
+
 test('exception keywords reuse C++ scopes and ignore non-keyword occurrences', () => {
 	for (const [word, scope] of [
 		['TRY', 'keyword.control.try.cpp'],
@@ -82,7 +118,7 @@ test('comments, strings, lowercase and keyword prefixes cannot become keywords',
 	for (const text of ['c_int', 'C_INTValue', 'MyC_INT', 'C_TYPE_1']) {
 		assert.ok(!scopesAt(text, text).some(s => s.startsWith('storage.')), text);
 	}
-	for (const text of ['if X then', 'IFValue <- 1', 'CASE OF X', 'CLASS Example']) {
+	for (const text of ['if X then', 'IFValue <- 1', 'SET OF X', 'DEFINE X', 'RANDOM']) {
 		assert.ok(!scopesAt(text, text.split(' ')[0]).some(
 			s => /^(keyword|storage)\./.test(s)), text);
 	}