hare

commit 27f960cc6387f9ee0ef5003a55580105bc939662
parent f476566936a2477e30caab1cfbd90257d873a851
Author: Sebastian <sebastian@sebsite.pw>
Date:   Fri, 29 Sep 2023 22:19:50 -0400

hare::ast: remove default field from match_expr

The _type field in match_case is already nullable, and not separating
the two preserves the location of the default case relative to the other
cases within the AST.

This removes the check in hare::parse for a duplicate default case,
which is fine since this doesn't belong in the parser anyway.

Signed-off-by: Sebastian <sebastian@sebsite.pw>

Diffstat:
M
hare/ast/expr.ha
 | 
7
+------
M
hare/parse/expr.ha
 | 
23
++++-------------------
M
hare/unparse/expr.ha
 | 
8
--------

3 files changed, 5 insertions(+), 33 deletions(-)
diff --git a/hare/ast/expr.ha b/hare/ast/expr.ha
@@ -312,7 +312,7 @@ export type len_expr = *expr;
 //	case let name: type => exprs
 export type match_case = struct {
 	name: str,
-	_type: nullable *_type,
+	_type: nullable *_type, // null for default case
 	exprs: []*expr,
 };
 
@@ -322,7 +322,6 @@ export type match_case = struct {
 export type match_expr = struct {
 	value: *expr,
 	cases: []match_case,
-	default: []*expr,
 };
 
 // An offset expression.
@@ -566,10 +565,6 @@ case let e: expr =>
 			free(exprs);
 		};
 		free(m.cases);
-		for (let i = 0z; i < len(m.default); i += 1) {
-			expr_finish(m.default[i]);
-		};
-		free(m.default);
 	case let o: offset_expr =>
 		expr_finish(o: *expr);
 	case let p: propagate_expr =>
diff --git a/hare/parse/expr.ha b/hare/parse/expr.ha
@@ -1139,6 +1139,7 @@ fn switch_expr(lexer: *lex::lexer) (ast::expr | error) = {
 };
 
 fn match_case(lexer: *lex::lexer) (ast::match_case | error) = {
+	want(lexer, ltok::CASE)?;
 	let tok = lex::lex(lexer)?;
 	let loc = tok.2;
 	let name: str = "", typ: nullable *ast::_type = null;
@@ -1154,7 +1155,8 @@ fn match_case(lexer: *lex::lexer) (ast::match_case | error) = {
 		name = want(lexer, ltok::NAME)?.1 as str;
 		want(lexer, ltok::COLON)?;
 		typ = alloc(_type(lexer)?);
-	case ltok::ARROW => void;
+	case ltok::ARROW =>
+		lex::unlex(lexer, tok);
 	case =>
 		lex::unlex(lexer, tok);
 		typ = alloc(_type(lexer)?);
@@ -1183,24 +1185,8 @@ fn match_expr(lexer: *lex::lexer) (ast::expr | error) = {
 	want(lexer, ltok::LBRACE)?;
 
 	let cases: []ast::match_case = [];
-	let default: []*ast::expr = [];
 	for (true) {
-		want(lexer, ltok::CASE)?;
-
-		match (try(lexer, ltok::ARROW)?) {
-		case let t: lex::token =>
-			if (len(default) != 0) {
-				return syntaxerr(t.2,
-					"More than one default match case");
-			};
-			for (peek(lexer, ltok::CASE, ltok::RBRACE)? is void) {
-				append(default, alloc(expr(lexer)?));
-				want(lexer, ltok::SEMICOLON)?;
-			};
-		case void =>
-			append(cases, match_case(lexer)?);
-		};
-
+		append(cases, match_case(lexer)?);
 		if (try(lexer, ltok::RBRACE)? is lex::token) {
 			break;
 		};
@@ -1212,7 +1198,6 @@ fn match_expr(lexer: *lex::lexer) (ast::expr | error) = {
 		expr = ast::match_expr {
 			value   = alloc(value),
 			cases   = cases,
-			default = default,
 		},
 	};
 };
diff --git a/hare/unparse/expr.ha b/hare/unparse/expr.ha
@@ -869,14 +869,6 @@ fn match_expr(
 		z += case_exprs(ctx, syn, item.exprs)?;
 	};
 
-	if (len(e.default) != 0) {
-		z += newline(ctx)?;
-		z += syn(ctx, "case", synkind::KEYWORD)?;
-		z += space(ctx)?;
-		z += syn(ctx, "=>", synkind::OPERATOR)?;
-		z += case_exprs(ctx, syn, e.default)?;
-	};
-
 	z += newline(ctx)?;
 	z += syn(ctx, "}", synkind::PUNCTUATION)?;
 	return z;