Add support for C23/GNU C23 standard flags

CHANGELOG.md

@@ -23,6 +23,7 @@ Bug Fixes:
 - Fix incorrect parsing of environment variables with quoted values containing spaces. [#729](https://github.com/microsoft/vscode-makefile-tools/issues/729)
 - Fix build task failure where task definition was missing command property. [#748](https://github.com/microsoft/vscode-makefile-tools/issues/748)
 - Added support for C++23 and C++26 standard flags. [#752](https://github.com/microsoft/vscode-makefile-tools/issues/752)
+- Add support for C23 and GNU C23 standard flags (`c23`, `gnu23`, `c2x`, `gnu2x`) and fix `iso9899:*` year-based standard flags not being recognized across all C standard branches. [#803](https://github.com/microsoft/vscode-makefile-tools/issues/803)
 - Fix path link detection in output panel for non-English locales. [#723](https://github.com/microsoft/vscode-makefile-tools/issues/723)
 - Fix script path links not being clickable in localized output for CHS/CHT/DEU/FRA/PLK. [#724](https://github.com/microsoft/vscode-makefile-tools/issues/724)
 - Fix file path links not being clickable in output panel for certain locales. [#725](https://github.com/microsoft/vscode-makefile-tools/issues/725)

src/parser.ts

@@ -2244,19 +2244,26 @@ function parseCStandard(
 ): util.StandardVersion | undefined {
   // GNU options from: https://gcc.gnu.org/onlinedocs/gcc/C-Dialect-Options.html#C-Dialect-Options
   const isGnu: boolean = canUseGnu && std.startsWith("gnu");
-  if (/(c|gnu)(90|89|iso9899:(1990|199409))/.test(std)) {
+  if (/(c|gnu)(90|89)/.test(std) || /iso9899:(1990|199409)/.test(std)) {
     return isGnu ? "gnu89" : "c89";
-  } else if (/(c|gnu)(99|9x|iso9899:(1999|199x))/.test(std)) {
+  } else if (/(c|gnu)(99|9x)/.test(std) || /iso9899:(1999|199x)/.test(std)) {
     return isGnu ? "gnu99" : "c99";
-  } else if (/(c|gnu)(11|1x|iso9899:2011)/.test(std)) {
+  } else if (/(c|gnu)(11|1x)/.test(std) || /iso9899:2011/.test(std)) {
     return isGnu ? "gnu11" : "c11";
-  } else if (/(c|gnu)(17|18|23|2x|iso9899:(2017|2018|2024))/.test(std)) {
+  } else if (/(c|gnu)(17|18)/.test(std) || /iso9899:(2017|2018)/.test(std)) {
     if (canUseGnu) {
-      // cpptools supports 'c17' in same version it supports GNU std.
+      // cpptools v4+ supports 'c17'/'gnu17'; older versions fall back to 'c11'.
       return isGnu ? "gnu17" : "c17";
     } else {
       return "c11";
     }
+  } else if (/(c|gnu)(23|2x)/.test(std) || /iso9899:2024/.test(std)) {
+    if (canUseGnu) {
+      // cpptools v4+ supports 'c23'/'gnu23'; older versions fall back to 'c11'.
+      return isGnu ? "gnu23" : "c23";
+    } else {
+      return "c11";
+    }
   } else {
     return undefined;
   }

src/test/fakeSuite/extension.test.ts

@@ -1008,3 +1008,97 @@ suite("Unit testing parseStandard for C++ standards", () => {
     );
   });
 });
+
+suite("Unit testing parseStandard for C standards", () => {
+  suiteSetup(async function (this: Mocha.Context) {
+    this.timeout(100000);
+  });
+
+  test("Test C23 standard parsing", () => {
+    // Test c23 flag
+    expect(parser.parseStandard(cpp.Version.v6, "c23", "c")).to.be.equal(
+      "c23"
+    );
+    // Test c2x flag (draft name for C23)
+    expect(parser.parseStandard(cpp.Version.v6, "c2x", "c")).to.be.equal(
+      "c23"
+    );
+    // Test gnu23 flag
+    expect(parser.parseStandard(cpp.Version.v6, "gnu23", "c")).to.be.equal(
+      "gnu23"
+    );
+    // Test gnu2x flag
+    expect(parser.parseStandard(cpp.Version.v6, "gnu2x", "c")).to.be.equal(
+      "gnu23"
+    );
+    // Test iso9899:2024 flag
+    expect(
+      parser.parseStandard(cpp.Version.v6, "iso9899:2024", "c")
+    ).to.be.equal("c23");
+    // Test c23 falls back to c11 on cpptools < v4
+    expect(parser.parseStandard(cpp.Version.v3, "c23", "c")).to.be.equal(
+      "c11"
+    );
+    expect(parser.parseStandard(cpp.Version.v3, "gnu23", "c")).to.be.equal(
+      "c11"
+    );
+  });
+
+  test("Test C17 standard parsing", () => {
+    // Test c17 flag
+    expect(parser.parseStandard(cpp.Version.v6, "c17", "c")).to.be.equal(
+      "c17"
+    );
+    // Test c18 flag
+    expect(parser.parseStandard(cpp.Version.v6, "c18", "c")).to.be.equal(
+      "c17"
+    );
+    // Test gnu17 flag
+    expect(parser.parseStandard(cpp.Version.v6, "gnu17", "c")).to.be.equal(
+      "gnu17"
+    );
+    // Test gnu18 flag
+    expect(parser.parseStandard(cpp.Version.v6, "gnu18", "c")).to.be.equal(
+      "gnu17"
+    );
+    // Test iso9899:2017 flag
+    expect(
+      parser.parseStandard(cpp.Version.v6, "iso9899:2017", "c")
+    ).to.be.equal("c17");
+    // Test iso9899:2018 flag
+    expect(
+      parser.parseStandard(cpp.Version.v6, "iso9899:2018", "c")
+    ).to.be.equal("c17");
+  });
+
+  test("Test older C standard parsing", () => {
+    // Test c11 flag
+    expect(parser.parseStandard(cpp.Version.v6, "c11", "c")).to.be.equal(
+      "c11"
+    );
+    // Test iso9899:2011 flag
+    expect(
+      parser.parseStandard(cpp.Version.v6, "iso9899:2011", "c")
+    ).to.be.equal("c11");
+    // Test c99 flag
+    expect(parser.parseStandard(cpp.Version.v6, "c99", "c")).to.be.equal(
+      "c99"
+    );
+    // Test iso9899:1999 flag
+    expect(
+      parser.parseStandard(cpp.Version.v6, "iso9899:1999", "c")
+    ).to.be.equal("c99");
+    // Test c89 flag
+    expect(parser.parseStandard(cpp.Version.v6, "c89", "c")).to.be.equal(
+      "c89"
+    );
+    // Test iso9899:1990 flag
+    expect(
+      parser.parseStandard(cpp.Version.v6, "iso9899:1990", "c")
+    ).to.be.equal("c89");
+    // Test iso9899:199409 flag
+    expect(
+      parser.parseStandard(cpp.Version.v6, "iso9899:199409", "c")
+    ).to.be.equal("c89");
+  });
+});

src/util.ts

@@ -26,6 +26,7 @@ export type StandardVersion =
   | "c99"
   | "c11"
   | "c17"
+  | "c23"
   | "c++98"
   | "c++03"
   | "c++11"
@@ -38,6 +39,7 @@ export type StandardVersion =
   | "gnu99"
   | "gnu11"
   | "gnu17"
+  | "gnu23"
   | "gnu++98"
   | "gnu++03"
   | "gnu++11"