condtional multi-unwrap and guard clauses

2026-06-22 20:37:37 +02:00
parent 27f42dd253
commit 663f4dc658
9 changed files with 567 additions and 96 deletions
@@ -669,57 +669,117 @@ lower_statements :: proc(state: ^State, statements: []hir.Stmt_Id) {
 				diagnostic=statement.diagnostic,
 			})
 		case .If:
-			// A conditional unwrap (`if opt |v| { ... }`) carries the binding local id in
-			// `statement.local`; `expr` is then the optional, not a bool condition. Test it
-			// for presence, and inside the then-block bind the unwrapped value to the local.
-			is_unwrap := statement.local != hir.INVALID_LOCAL
-			opt := ir.INVALID_INSTRUCTION
-			cond: ir.Instruction_Id
-			if is_unwrap {
-				opt = lower_expr(state, statement.expr)
-				cond = append_instruction(state, ir.Instruction{
-					op=.Optional_Is_Some, span=statement.span, type=types.BOOL,
-					target=ir.INVALID_REF, a=opt, b=ir.INVALID_INSTRUCTION,
-					diagnostic=source.INVALID_DIAGNOSTIC,
-				})
-			} else {
-				cond = lower_expr(state, statement.expr)
-			}
 			has_else := statement.else_body != nil
 			then_lbl := fresh_label(state)
 			else_lbl := fresh_label(state) if has_else else then_lbl
 			merge_lbl := fresh_label(state)
 			false_target := else_lbl if has_else else merge_lbl
-			append_instruction(state, ir.Instruction{
-				op=.Cond_Br, span=statement.span, type=types.VOID,
-				a=cond, integer=then_lbl, target=ir.Ref(u32(false_target)),
-				b=ir.INVALID_INSTRUCTION, diagnostic=source.INVALID_DIAGNOSTIC,
-			})
+
+			if len(statement.unwraps) > 0 {
+				// Evaluate each optional exactly once, entering the next operand only
+				// after the previous one is present. Capture storage is initialized in
+				// these success blocks so the optional guard can use every binding.
+				for unwrap in statement.unwraps {
+					optional := lower_expr(state, unwrap.expr)
+					present := append_instruction(state, ir.Instruction{
+						op=.Optional_Is_Some,
+						span=statement.span,
+						type=types.BOOL,
+						target=ir.INVALID_REF,
+						a=optional,
+						b=ir.INVALID_INSTRUCTION,
+						diagnostic=source.INVALID_DIAGNOSTIC,
+					})
+					success_lbl := fresh_label(state)
+					append_instruction(state, ir.Instruction{
+						op=.Cond_Br,
+						span=statement.span,
+						type=types.VOID,
+						a=present,
+						integer=success_lbl,
+						target=ir.Ref(u32(false_target)),
+						b=ir.INVALID_INSTRUCTION,
+						diagnostic=source.INVALID_DIAGNOSTIC,
+					})
+					append_instruction(state, ir.Instruction{
+						op=.Label,
+						span=statement.span,
+						type=types.VOID,
+						integer=success_lbl,
+						target=ir.INVALID_REF,
+						a=ir.INVALID_INSTRUCTION,
+						b=ir.INVALID_INSTRUCTION,
+						diagnostic=source.INVALID_DIAGNOSTIC,
+					})
+					if unwrap.local != hir.INVALID_LOCAL && int(unwrap.local) < len(state.func_locals) {
+						local := state.func_locals[unwrap.local]
+						slot := append_instruction(state, ir.Instruction{
+							op=.Alloca,
+							span=statement.span,
+							type=local.type,
+							target=ir.local_ref(ir.Local_Id(unwrap.local)),
+							a=ir.INVALID_INSTRUCTION,
+							b=ir.INVALID_INSTRUCTION,
+							diagnostic=source.INVALID_DIAGNOSTIC,
+						})
+						state.local_slots[unwrap.local] = slot
+						inner := append_instruction(state, ir.Instruction{
+							op=.Optional_Value,
+							span=statement.span,
+							type=local.type,
+							target=ir.INVALID_REF,
+							a=optional,
+							b=ir.INVALID_INSTRUCTION,
+							diagnostic=source.INVALID_DIAGNOSTIC,
+						})
+						append_instruction(state, ir.Instruction{
+							op=.Store,
+							span=statement.span,
+							type=local.type,
+							target=ir.INVALID_REF,
+							a=slot,
+							b=inner,
+							diagnostic=source.INVALID_DIAGNOSTIC,
+						})
+					}
+				}
+				if statement.guard != hir.INVALID_EXPR {
+					guard := lower_expr(state, statement.guard)
+					append_instruction(state, ir.Instruction{
+						op=.Cond_Br,
+						span=statement.span,
+						type=types.VOID,
+						a=guard,
+						integer=then_lbl,
+						target=ir.Ref(u32(false_target)),
+						b=ir.INVALID_INSTRUCTION,
+						diagnostic=source.INVALID_DIAGNOSTIC,
+					})
+				} else {
+					append_instruction(state, ir.Instruction{
+						op=.Br,
+						span=statement.span,
+						type=types.VOID,
+						integer=then_lbl,
+						target=ir.INVALID_REF,
+						a=ir.INVALID_INSTRUCTION,
+						b=ir.INVALID_INSTRUCTION,
+						diagnostic=source.INVALID_DIAGNOSTIC,
+					})
+				}
+			} else {
+				cond := lower_expr(state, statement.expr)
+				append_instruction(state, ir.Instruction{
+					op=.Cond_Br, span=statement.span, type=types.VOID,
+					a=cond, integer=then_lbl, target=ir.Ref(u32(false_target)),
+					b=ir.INVALID_INSTRUCTION, diagnostic=source.INVALID_DIAGNOSTIC,
+				})
+			}
 			append_instruction(state, ir.Instruction{
 				op=.Label, span=statement.span, type=types.VOID, integer=then_lbl,
 				target=ir.INVALID_REF, a=ir.INVALID_INSTRUCTION, b=ir.INVALID_INSTRUCTION,
 				diagnostic=source.INVALID_DIAGNOSTIC,
 			})
-			if is_unwrap && int(statement.local) < len(state.func_locals) {
-				local := state.func_locals[statement.local]
-				slot := append_instruction(state, ir.Instruction{
-					op=.Alloca, span=statement.span, type=local.type,
-					target=ir.local_ref(ir.Local_Id(statement.local)),
-					a=ir.INVALID_INSTRUCTION, b=ir.INVALID_INSTRUCTION,
-					diagnostic=source.INVALID_DIAGNOSTIC,
-				})
-				state.local_slots[statement.local] = slot
-				inner := append_instruction(state, ir.Instruction{
-					op=.Optional_Value, span=statement.span, type=local.type,
-					target=ir.INVALID_REF, a=opt, b=ir.INVALID_INSTRUCTION,
-					diagnostic=source.INVALID_DIAGNOSTIC,
-				})
-				append_instruction(state, ir.Instruction{
-					op=.Store, span=statement.span, type=local.type,
-					target=ir.INVALID_REF, a=slot, b=inner,
-					diagnostic=source.INVALID_DIAGNOSTIC,
-				})
-			}
 			lower_statements(state, statement.then_body)
 			append_instruction(state, ir.Instruction{
 				op=.Br, span=statement.span, type=types.VOID, integer=merge_lbl,