hare

commit e952359b927844a2176aeffb9d82adad69ba647b
parent ef705aaf200fe260eb2cb71641801d0a08b45ded
Author: Eyal Sawady <ecs@d2evs.net>
Date:   Sun, 25 Apr 2021 01:23:36 -0400

hare::parse: implement ! postfix operator

Co-authored-by: Drew DeVault <sir@cmpwn.com>
Signed-off-by: Eyal Sawady <ecs@d2evs.net>
Signed-off-by: Drew DeVault <sir@cmpwn.com>

Diffstat:
M
hare/ast/expr.ha
 | 
7
+++++--
M
hare/parse/+test/expr.ha
 | 
1
+
M
hare/parse/expr.ha
 | 
17
+++++++++++------
M
hare/unparse/expr.ha
 | 
4
++--

4 files changed, 19 insertions(+), 10 deletions(-)
diff --git a/hare/ast/expr.ha b/hare/ast/expr.ha
@@ -278,7 +278,10 @@ export type offset_expr = void; // TODO
 // An error propagation expression.
 //
 // 	foo?
-export type propagate_expr = *expr;
+export type propagate_expr = struct {
+	is_abort: bool,
+	expr: *expr,
+};
 
 // A return statement.
 //
@@ -477,7 +480,7 @@ export fn expr_free(e: (expr | nullable *expr)) void = match (e) {
 			free(m.cases);
 		},
 		o: offset_expr => abort(), // TODO
-		p: propagate_expr => expr_free(p: *expr),
+		p: propagate_expr => expr_free(p.expr),
 		r: return_expr => expr_free(r: *expr),
 		s: size_expr => type_free(s: *_type),
 		s: slice_expr => {
diff --git a/hare/parse/+test/expr.ha b/hare/parse/+test/expr.ha
@@ -186,6 +186,7 @@
 		"export fn main() void = x.42;\n"
 		"export fn main() void = x().y.0.q;\n"
 		"export fn main() void = x?;\n"
+		"export fn main() void = x!;\n"
 		"export fn main() void = x()?.y;\n"
 		"export fn main() void = x[10];\n"
 		"export fn main() void = x[10 + 10][20];\n");
diff --git a/hare/parse/expr.ha b/hare/parse/expr.ha
@@ -728,19 +728,24 @@ fn postfix(lexer: *lex::lexer, lvalue: (ast::expr | void)) (ast::expr | error) =
 		ex: ast::expr => ex,
 	};
 
-	lvalue = match (try(lexer, ltok::LPAREN,
-			ltok::DOT, ltok::LBRACKET, ltok::QUESTION)) {
+	return postfix(lexer, match (try(lexer, ltok::LPAREN,
+			ltok::DOT, ltok::LBRACKET, ltok::QUESTION, ltok::LNOT)) {
 		tok: lex::token => switch (tok.0) {
 			ltok::LPAREN => call(lexer, lvalue)?,
 			ltok::DOT => postfix_dot(lexer, lvalue)?,
 			ltok::LBRACKET => indexing(lexer, lvalue)?,
-			ltok::QUESTION => alloc(lvalue): ast::propagate_expr,
+			ltok::QUESTION => ast::propagate_expr {
+				is_abort = false,
+				expr = alloc(lvalue),
+			},
+			ltok::LNOT => ast::propagate_expr {
+				is_abort = true,
+				expr = alloc(lvalue),
+			},
 			* => abort(),
 		},
 		_: void => return lvalue,
-	};
-
-	return postfix(lexer, lvalue);
+	});
 };
 
 fn postfix_dot(lexer: *lex::lexer, lvalue: ast::expr) (ast::expr | error) = {
diff --git a/hare/unparse/expr.ha b/hare/unparse/expr.ha
@@ -257,8 +257,8 @@ export fn expr(
 		},
 		e: ast::offset_expr => abort(),
 		e: ast::propagate_expr => {
-			let z = expr(out, indent, *e)?;
-			z + fmt::fprintf(out, "?")?;
+			let z = expr(out, indent, *e.expr)?;
+			z + fmt::fprintf(out, if (e.is_abort) "!" else "?")?;
 		},
 		e: ast::return_expr => {
 			let z = fmt::fprint(out, "return")?;