hare

commit 87a80a82b7490f7fad4efb538520a8369cb1b76b
parent 1a7acbf2462917c018759634563432b927c1ea9a
Author: Drew DeVault <sir@cmpwn.com>
Date:   Fri, 16 Apr 2021 09:48:39 -0400

hare::parse: implement error propagation

Diffstat:
M
hare/parse/+test/expr.ha
 | 
4
+++-
M
hare/parse/expr.ha
 | 
14
+++++++++-----
M
hare/unparse/expr.ha
 | 
5
++++-

3 files changed, 16 insertions(+), 7 deletions(-)
diff --git a/hare/parse/+test/expr.ha b/hare/parse/+test/expr.ha
@@ -26,7 +26,9 @@
 		"export fn main() void = x.y.z.q;\n"
 		"export fn main() void = x().y;\n"
 		"export fn main() void = x.42;\n"
-		"export fn main() void = x().y.0.q;\n");
+		"export fn main() void = x().y.0.q;\n"
+		"export fn main() void = x?;\n"
+		"export fn main() void = x()?.y;\n");
 };
 
 @test fn unarithm() void = {
diff --git a/hare/parse/expr.ha b/hare/parse/expr.ha
@@ -208,13 +208,17 @@ 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)) {
+	match (try(lexer, ltok::LPAREN, ltok::DOT, ltok::LBRACKET, ltok::QUESTION)) {
 		tok: lex::token => switch (tok.0) {
-			ltok::LPAREN => call(lexer, lvalue)?,
-			ltok::DOT => postfix_dot(lexer, lvalue)?,
+			ltok::LPAREN => lvalue = call(lexer, lvalue)?,
+			ltok::DOT => lvalue = postfix_dot(lexer, lvalue)?,
 			ltok::LBRACKET => abort(), // TODO: Indexing
-			ltok::QUESTION => abort(), // TODO: Propagation
+			ltok::QUESTION => {
+				// Crappy workaround for harec bug
+				// https://todo.sr.ht/~sircmpwn/hare/377
+				let new = alloc(lvalue): ast::propagate_expr;
+				lvalue = new;
+			},
 			* => abort(),
 		},
 		void => return lvalue,
diff --git a/hare/unparse/expr.ha b/hare/unparse/expr.ha
@@ -92,7 +92,10 @@ export fn expr(
 		e: ast::len_expr => abort(),
 		e: ast::size_expr => abort(),
 		e: ast::offset_expr => abort(),
-		e: ast::propagate_expr => abort(),
+		e: ast::propagate_expr => {
+			let z = expr(out, indent, *e)?;
+			z + fmt::fprintf(out, "?")?;
+		},
 		e: ast::return_expr => abort(),
 		e: ast::slice_expr => abort(),
 		e: ast::switch_expr => abort(),