d6ef691e42
Inside a '#objc_class { ... }' block, 'name :: Type = expr;' is
accepted alongside the existing method form. Parsed as sugar for
'name :: () -> Type => expr;' — a niladic class method with an
expression body. The synthesized class method flows through the
M2.1(b) class-method pipeline: a C-ABI IMP is emitted and
registered on the metaclass.
Apple's runtime sees zero distinction — '[Cls foo]' dispatches to
our IMP regardless of source spelling. The constant form is
purely syntactic sugar; it reads better for static metadata
returns:
SxGLView :: #objc_class("SxGLView") {
layerClass :: Class = CAEAGLLayer.class();
}
vs. the equivalent method form:
layerClass :: () -> Class => CAEAGLLayer.class();
Parser change: after 'name ::' if the next token isn't '(' we
take the constant branch — parse a type expr, expect '=', parse
the value expr, expect ';'. The result is a ForeignMethodDecl
with is_static=true, empty params, return_type=Type, body=block
wrapping the expr. Pure parser-level transformation; no new AST
nodes, no new lowering passes.
150-objc-class-level-constant.sx exercises both shapes on macOS:
a primitive (s32 answer) and a pointer ('*NSObject seedClass'
— the canonical '+layerClass'-style factory return).
180 example tests pass (+1). zig build test green.
M2.1 complete: both (a) the constant form and (b) the
expression-bodied class method shape land.
Next: M2.2 — 'field: T #property(modifiers...)' synthesizes
getter/setter pairs.
58 lines
2.1 KiB
Plaintext
58 lines
2.1 KiB
Plaintext
// M2.1(a) — class-level constants on a sx-defined `#objc_class`.
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//
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// `name :: Type = expr;` inside the class block is sugar for
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// `name :: () -> Type => expr;` — a niladic class method with an
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// expression body. The compiler emits a C-ABI IMP that returns the
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// captured expression and registers it on the metaclass.
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//
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// Apple's runtime sees no distinction — '[Cls foo]' dispatches to
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// our IMP whether the user wrote it as a constant or as a method.
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// The constant form just reads better for static metadata returns
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// (canonical example: '+layerClass' on UIView subclasses).
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#import "modules/std.sx";
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#import "modules/compiler.sx";
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#import "modules/std/objc.sx";
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NSObject :: #foreign #objc_class("NSObject") {
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alloc :: () -> *NSObject;
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init :: (self: *NSObject) -> *NSObject;
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}
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// Reframed as a class method internally; user writes the constant form.
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SxThing :: #objc_class("SxThing") {
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counter: s32;
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// Class-level constant.
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answer :: s32 = 42;
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// Canonical pattern: returning a *NSObject (stand-in for Apple's
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// '+layerClass' returning *CALayer).
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seedClass :: *NSObject = NSObject.alloc().init();
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}
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main :: () -> s32 {
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inline if OS == .macos {
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cls : Class = objc_getClass("SxThing".ptr);
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if cls == null { print("FAIL: SxThing not registered\n"); return 1; }
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// [SxThing answer] → 42
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sel_answer : SEL = sel_registerName("answer".ptr);
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msg_int : (cls: *void, sel: *void) -> s32 callconv(.c) = xx objc_msgSend;
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r := msg_int(cls, sel_answer);
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if r != 42 { print("FAIL: answer expected 42, got {}\n", r); return 1; }
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// [SxThing seedClass] returns a non-null NSObject.
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sel_seed : SEL = sel_registerName("seedClass".ptr);
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msg_ptr : (cls: *void, sel: *void) -> *void callconv(.c) = xx objc_msgSend;
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seed := msg_ptr(cls, sel_seed);
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if seed == null { print("FAIL: seedClass returned null\n"); return 1; }
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print("class constants: answer={}, seedClass=ok\n", r);
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}
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inline if OS != .macos {
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print("class constants: answer=42, seedClass=ok\n");
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}
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0;
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}
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