feat(extract): index Metal (.metal) shader files (#1480)

Metal Shading Language is C++14, so .metal files are classified as code and routed
through the existing C++ extractor, mirroring the CUDA .cu/.cuh reuse. Also adds
.cu/.cuh/.metal to build.py's _LANG_FAMILY map (they were all missing), so the
cross-language phantom-`calls`-edge filter treats them as C++. README language
table updated.

Ported from PR #1480 by @jiangyq9. This supersedes the earlier #1450 by
@GoodOlClint (same .metal -> C++ approach and fixture) — credit to @GoodOlClint
for the original; #1480 additionally closes the CUDA family-map gap and updates
the docs, and merges clean against current v8.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

README.md

@@ -242,7 +242,7 @@ To remove graphify from all platforms at once: `graphify uninstall` (add `--purg
 
 | Type | Extensions |
 |------|-----------|
-| Code (36 tree-sitter grammars) | `.py .ts .js .jsx .tsx .mjs .go .rs .java .c .cpp .h .hpp .cu .cuh .rb .cs .kt .scala .php .swift .lua .luau .zig .ps1 .psm1 .ex .exs .m .mm .jl .vue .svelte .astro .groovy .gradle .dart .v .sv .svh .sql .f .f90 .f95 .f03 .f08 .pas .pp .dpr .dpk .lpr .inc .dfm .lfm .lpk .sh .bash .json .dm .dme .dmi .dmm .dmf .sln .slnx .csproj .fsproj .vbproj .xaml .razor .cshtml` (`.dm`/`.dme` requires `uv tool install graphifyy[dm]`; CUDA `.cu`/`.cuh` reuse the C++ grammar) |
+| Code (36 tree-sitter grammars) | `.py .ts .js .jsx .tsx .mjs .go .rs .java .c .cpp .h .hpp .cu .cuh .metal .rb .cs .kt .scala .php .swift .lua .luau .zig .ps1 .psm1 .ex .exs .m .mm .jl .vue .svelte .astro .groovy .gradle .dart .v .sv .svh .sql .f .f90 .f95 .f03 .f08 .pas .pp .dpr .dpk .lpr .inc .dfm .lfm .lpk .sh .bash .json .dm .dme .dmi .dmm .dmf .sln .slnx .csproj .fsproj .vbproj .xaml .razor .cshtml` (`.dm`/`.dme` requires `uv tool install graphifyy[dm]`; CUDA `.cu`/`.cuh` and Metal `.metal` reuse the C++ grammar) |
 | Salesforce Apex | `.cls .trigger` (regex-based; classes, interfaces, enums, methods, triggers, SOQL/DML edges) |
 | Terraform / HCL | `.tf .tfvars .hcl` (requires `uv tool install graphifyy[terraform]`) |
 | MCP configs | `.mcp.json` `mcp.json` `mcp_servers.json` `claude_desktop_config.json` — extracts server nodes, package refs, env var requirements |

graphify/build.py

@@ -336,6 +336,7 @@ def build_from_json(extraction: dict, *, directed: bool = False, root: str | Pat
                 ".go": "go", ".rs": "rs",
                 ".java": "jvm", ".kt": "jvm", ".scala": "jvm", ".groovy": "jvm",
                 ".c": "c", ".h": "c", ".cc": "cpp", ".cpp": "cpp", ".hpp": "cpp",
+                ".cu": "cpp", ".cuh": "cpp", ".metal": "cpp",
                 ".rb": "rb", ".php": "php", ".cs": "cs", ".swift": "swift", ".lua": "lua",
             }
             src_ext = Path(G.nodes[src].get("source_file") or "").suffix.lower()

graphify/detect.py

@@ -27,7 +27,7 @@ class FileType(str, Enum):
 
 _MANIFEST_PATH = str(out_path("manifest.json"))
 
-CODE_EXTENSIONS = {'.py', '.ts', '.tsx', '.js', '.jsx', '.mjs', '.ejs', '.ets', '.go', '.rs', '.java', '.groovy', '.gradle', '.cpp', '.cc', '.cxx', '.c', '.h', '.hpp', '.cu', '.cuh', '.rb', '.swift', '.kt', '.kts', '.cs', '.scala', '.php', '.lua', '.luau', '.toc', '.zig', '.ps1', '.psm1', '.psd1', '.ex', '.exs', '.m', '.mm', '.jl', '.vue', '.svelte', '.astro', '.dart', '.v', '.sv', '.svh', '.sql', '.r', '.f', '.F', '.f90', '.F90', '.f95', '.F95', '.f03', '.F03', '.f08', '.F08', '.pas', '.pp', '.dpr', '.dpk', '.lpr', '.inc', '.dfm', '.lfm', '.lpk', '.sh', '.bash', '.json', '.tf', '.tfvars', '.hcl', '.dm', '.dme', '.dmi', '.dmm', '.dmf', '.sln', '.slnx', '.csproj', '.fsproj', '.vbproj', '.xaml', '.razor', '.cshtml', '.cls', '.trigger'}
+CODE_EXTENSIONS = {'.py', '.ts', '.tsx', '.js', '.jsx', '.mjs', '.ejs', '.ets', '.go', '.rs', '.java', '.groovy', '.gradle', '.cpp', '.cc', '.cxx', '.c', '.h', '.hpp', '.cu', '.cuh', '.metal', '.rb', '.swift', '.kt', '.kts', '.cs', '.scala', '.php', '.lua', '.luau', '.toc', '.zig', '.ps1', '.psm1', '.psd1', '.ex', '.exs', '.m', '.mm', '.jl', '.vue', '.svelte', '.astro', '.dart', '.v', '.sv', '.svh', '.sql', '.r', '.f', '.F', '.f90', '.F90', '.f95', '.F95', '.f03', '.F03', '.f08', '.F08', '.pas', '.pp', '.dpr', '.dpk', '.lpr', '.inc', '.dfm', '.lfm', '.lpk', '.sh', '.bash', '.json', '.tf', '.tfvars', '.hcl', '.dm', '.dme', '.dmi', '.dmm', '.dmf', '.sln', '.slnx', '.csproj', '.fsproj', '.vbproj', '.xaml', '.razor', '.cshtml', '.cls', '.trigger'}
 DOC_EXTENSIONS = {'.md', '.mdx', '.qmd', '.txt', '.rst', '.html', '.yaml', '.yml'}
 PAPER_EXTENSIONS = {'.pdf'}
 IMAGE_EXTENSIONS = {'.png', '.jpg', '.jpeg', '.gif', '.webp', '.svg'}

graphify/extract.py

@@ -12750,6 +12750,7 @@ _DISPATCH: dict[str, Any] = {
     ".hpp": extract_cpp,
     ".cu": extract_cpp,
     ".cuh": extract_cpp,
+    ".metal": extract_cpp,
     ".rb": extract_ruby,
     ".cs": extract_csharp,
     ".kt": extract_kotlin,

tests/fixtures/sample.metal

@@ -0,0 +1,21 @@
+#include <metal_stdlib>
+using namespace metal;
+
+struct Vec3 {
+    float x;
+    float y;
+    float z;
+};
+
+float dot3(Vec3 a, Vec3 b) {
+    return a.x * b.x + a.y * b.y + a.z * b.z;
+}
+
+kernel void saxpy(
+    device const float* x [[buffer(0)]],
+    device float* y [[buffer(1)]],
+    constant float& a [[buffer(2)]],
+    uint id [[thread_position_in_grid]]
+) {
+    y[id] = a * x[id] + y[id];
+}

tests/test_languages.py

@@ -257,6 +257,27 @@ def test_cuda_host_call_edges():
     assert ("main()", "host_norm()") in calls
 
 
+# Metal Shading Language is a C++14-derived language, so .metal files route
+# through the C++ extractor just like CUDA does.
+
+def test_metal_is_code_extension():
+    from graphify.detect import CODE_EXTENSIONS
+    assert ".metal" in CODE_EXTENSIONS
+
+
+def test_metal_no_error():
+    r = extract_cpp(FIXTURES / "sample.metal")
+    assert "error" not in r
+
+
+def test_metal_finds_kernel_function_and_struct():
+    r = extract_cpp(FIXTURES / "sample.metal")
+    labels = _labels(r)
+    assert any("Vec3" in l for l in labels)
+    assert any("dot3" in l for l in labels)
+    assert any("saxpy" in l for l in labels)
+
+
 # ── Ruby ─────────────────────────────────────────────────────────────────────
 
 def test_ruby_no_error():