bdd0e96d78
A block's value is now its last statement ONLY when that statement is a trailing expression with no `;`. A trailing `;` discards the value, leaving the block void. This makes value-vs-statement explicit and lets the compiler reject "this block was supposed to produce a value". Compiler: - Parser records `Block.produces_value` (last stmt is a no-`;` trailing expression) + `Block.discarded_semi` (the `;` that discarded a value), via `expectSemicolonAfter`. A trailing expression before `}` may now omit its `;` (previously a parse error). Match-arm and else-arm bodies are built value-producing regardless of the arm `;` (arms are exempt — the `;` is an arm terminator). - Lowering: `lowerBlockValue` / the block-expr path / `inferExprType` respect `produces_value`. A value-position block that discards its value is a hard error (`lowerValueBody` for function bodies; the value-context `.block` path for if/else branches, `catch` bodies, value bindings, match arms). Pure-failable `-> !` bodies (value rides the error channel) and a value-if whose branches are void are handled without false errors. - `defer`/`onfail` cleanup bodies lower as statements (void), so a trailing `;` there is fine. Migration (behavior-preserving — output unchanged): - stdlib + ~210 examples: dropped the trailing `;` on value-position last expressions. `format` now ends with an explicit `#insert "return result;"` (it relied on `#insert`-as-block-value, which `;` discards). - Two `main :: () -> s32` examples that relied on the old silent default-return got an explicit trailing `0`. - Rejection snapshots 0412 / 1013 regenerated (their quoted source lines lost a `;`); the diagnostics themselves are unchanged. Docs/tests: specs.md "Block values" section; examples 0040 (rules) + 0041 (rejection); 3 parser unit tests. Filed issue 0066 (pre-existing match-arm negated-literal phi-width quirk, surfaced not caused here). Gates: zig build, zig build test, run_examples.sh -> 343 passed, cross_compile.sh -> 7 passed (also refreshed its stale example names).
121 lines
3.9 KiB
Plaintext
121 lines
3.9 KiB
Plaintext
// iOS-only: bring up UIKitPlatform in Metal mode, clear the screen dark
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// blue each frame, then draw a colored triangle via the GPU protocol —
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// exercises create_shader (MSL compile + pipeline state), create_buffer
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// + update_buffer, set_shader, set_vertex_buffer, and draw_triangles.
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// Step 3b will port the UI renderer to use this same surface.
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//
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// Build for iOS sim:
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// /Users/agra/projects/sx/zig-out/bin/sx build --target ios-sim \
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// examples/63-metal-clear.sx \
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// -o /tmp/MetalClear --bundle /tmp/MetalClear.app \
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// --bundle-id co.swipelab.metalclear -F ~/Library/Frameworks
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// codesign --force --sign - --timestamp=none /tmp/MetalClear.app
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// xcrun simctl install booted /tmp/MetalClear.app
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// xcrun simctl launch --terminate-running-process booted co.swipelab.metalclear
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//
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// This file is iOS-only and not part of the JIT regression suite (no
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// tests/expected/63-metal-clear.txt). The test runner skips it on macOS.
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#import "modules/std.sx";
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#import "modules/std/objc.sx";
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#import "modules/compiler.sx";
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#import "modules/platform/api.sx";
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#import "modules/platform/uikit.sx";
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#import "modules/gpu/api.sx";
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#import "modules/gpu/metal.sx";
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#framework "UIKit";
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#framework "QuartzCore";
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#framework "OpenGLES";
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// Pass-through vertex + fragment shader for a colored triangle. Vertex
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// layout is { packed_float2 pos; packed_float4 color; } = 24 bytes —
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// `packed_*` types have 4-byte alignment so the struct doesn't get
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// padded between fields (a plain `float4` would force 16-byte alignment
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// and pad the struct out to 32 bytes per vertex). Entry-point names
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// (vmain / fmain) match what MetalGPU.create_shader looks up.
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TRI_MSL :: #string MSL
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#include <metal_stdlib>
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using namespace metal;
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struct Vertex {
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packed_float2 pos;
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packed_float4 color;
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};
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struct RasterizerData {
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float4 position [[position]];
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float4 color;
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};
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vertex RasterizerData vmain(uint vid [[vertex_id]],
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constant Vertex* vertices [[buffer(0)]]) {
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RasterizerData out;
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out.position = float4(vertices[vid].pos, 0.0, 1.0);
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out.color = float4(vertices[vid].color);
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return out;
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}
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fragment float4 fmain(RasterizerData in [[stage_in]]) {
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return in.color;
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}
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MSL;
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TRI_VERTS : [18]f32 = .[
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-0.6, -0.4, 1.0, 0.0, 0.0, 1.0,
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0.6, -0.4, 0.0, 1.0, 0.0, 1.0,
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0.0, 0.6, 0.0, 0.0, 1.0, 1.0,
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];
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g_plat : *UIKitPlatform = null;
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g_gpu : *MetalGPU = null;
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g_shader : ShaderHandle = 0;
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g_vbuf : BufferHandle = 0;
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frame :: () {
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if g_plat == null { return; }
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if g_gpu == null { return; }
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// Lazy-init the GPU on the first frame where the layer is available
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// (the layer is created during -[SxAppDelegate didFinishLaunching:]
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// which fires AFTER our main() returns into UIApplicationMain).
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if g_gpu.layer == null {
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if g_plat.gl_layer == null { return; }
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if !g_gpu.init(g_plat.gl_layer, g_plat.pixel_w, g_plat.pixel_h) { return; }
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}
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// Compile shader + upload vertex buffer once.
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if g_shader == 0 {
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g_shader = g_gpu.create_shader(TRI_MSL, "");
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if g_shader == 0 { return; }
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}
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if g_vbuf == 0 {
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g_vbuf = g_gpu.create_buffer(72); // 3 verts × 24 bytes
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if g_vbuf == 0 { return; }
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g_gpu.update_buffer(g_vbuf, xx @TRI_VERTS, 72);
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}
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bg : ClearColor = .{ r = 0.07, g = 0.10, b = 0.18, a = 1.0 };
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if !g_gpu.begin_frame(bg) { return; }
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g_gpu.set_shader(g_shader);
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g_gpu.set_vertex_buffer(g_vbuf);
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g_gpu.draw_triangles(0, 3);
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g_gpu.end_frame(0.0);
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}
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main :: () -> s32 {
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inline if OS != .ios { return 0; }
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plat : *UIKitPlatform = xx context.allocator.alloc(size_of(UIKitPlatform));
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plat.gpu_mode = .metal;
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if !plat.init("Metal Clear", 0, 0) { return 1; }
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g_plat = plat;
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gpu : *MetalGPU = xx context.allocator.alloc(size_of(MetalGPU));
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g_gpu = gpu;
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plat.run_frame_loop(closure(frame));
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plat.shutdown();
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0
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}
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