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).
129 lines
3.7 KiB
Plaintext
Executable File
129 lines
3.7 KiB
Plaintext
Executable File
#import "modules/std.sx";
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#import "modules/math";
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#import "modules/ui/types.sx";
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#import "modules/ui/events.sx";
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GesturePhase :: enum {
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possible;
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began;
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changed;
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ended;
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cancelled;
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failed;
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}
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// --- TapGesture ---
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TapValue :: struct {
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location: Point;
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count: s32;
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}
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TapGesture :: struct {
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count: s32;
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on_tap: ?Closure();
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phase: GesturePhase;
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tap_count: s32;
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start_position: Point;
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TAP_THRESHOLD :f32: 10.0;
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handle_event :: (self: *TapGesture, event: *Event, frame: Frame) -> bool {
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if event.* == {
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case .mouse_down: (d) {
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if frame.contains(d.position) {
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self.phase = .began;
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self.start_position = d.position;
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return true;
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}
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}
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case .mouse_moved: (d) {
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if self.phase == .began {
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if self.start_position.distance(d.position) > TapGesture.TAP_THRESHOLD {
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self.phase = .failed;
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}
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}
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}
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case .mouse_up: (d) {
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if self.phase == .began {
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if frame.contains(d.position) {
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self.tap_count += 1;
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if self.tap_count >= self.count {
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if handler := self.on_tap { handler(); }
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self.tap_count = 0;
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}
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}
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}
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self.phase = .possible;
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return true;
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}
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}
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false
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}
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}
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// --- DragGesture ---
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DragValue :: struct {
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location: Point;
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start_location: Point;
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translation: Point;
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}
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DragGesture :: struct {
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min_distance: f32;
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on_changed: ?Closure(DragValue);
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on_ended: ?Closure(DragValue);
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phase: GesturePhase;
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start_location: Point;
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current_location: Point;
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make_value :: (self: *DragGesture) -> DragValue {
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DragValue.{
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location = self.current_location,
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start_location = self.start_location,
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translation = self.current_location.sub(self.start_location)
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}
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}
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handle_event :: (self: *DragGesture, event: *Event, frame: Frame) -> bool {
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if event.* == {
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case .mouse_down: (d) {
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if frame.contains(d.position) {
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self.phase = .possible;
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self.start_location = d.position;
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self.current_location = d.position;
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return true;
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}
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}
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case .mouse_moved: (d) {
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if self.phase == .possible {
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self.current_location = d.position;
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if self.start_location.distance(d.position) >= self.min_distance {
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self.phase = .began;
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if handler := self.on_changed { handler(self.make_value()); }
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}
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return true;
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}
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if self.phase == .began or self.phase == .changed {
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self.current_location = d.position;
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self.phase = .changed;
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if handler := self.on_changed { handler(self.make_value()); }
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return true;
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}
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}
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case .mouse_up: (d) {
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if self.phase == .began or self.phase == .changed {
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self.current_location = d.position;
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self.phase = .ended;
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if handler := self.on_ended { handler(self.make_value()); }
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self.phase = .possible;
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return true;
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}
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self.phase = .possible;
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}
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}
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false
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}
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}
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