hare

commit 3db5510b45e63de415152fd2c17e013581f0a37c
parent 487dc87f11de11cf66d49f95088099745c9cd1fc
Author: Drew DeVault <sir@cmpwn.com>
Date:   Sat, 17 Apr 2021 08:24:55 -0400

hare::parse: implement control expressions

Diffstat:
M
hare/ast/expr.ha
 | 
2
+-
M
hare/parse/+test/expr.ha
 | 
20
++++++++++++++++----
M
hare/parse/expr.ha
 | 
16
+++++++++++++++-
M
hare/unparse/expr.ha
 | 
32
+++++++++++++++++++++++++++++---

4 files changed, 61 insertions(+), 9 deletions(-)
diff --git a/hare/ast/expr.ha b/hare/ast/expr.ha
@@ -201,7 +201,7 @@ export type offset_expr = void; // TODO
 export type propagate_expr = *expr;
 
 // return foo
-export type return_expr = *expr;
+export type return_expr = nullable *expr;
 
 // size(int)
 export type size_expr = *_type;
diff --git a/hare/parse/+test/expr.ha b/hare/parse/+test/expr.ha
@@ -2,10 +2,6 @@
 	roundtrip("export fn main() void = void + void * void / void;\n");
 };
 
-@test fn constant() void = {
-	roundtrip("export fn main() void = 2 + -4 + void + true + \"hello\" + '?';\n");
-};
-
 @test fn call() void = {
 	roundtrip("export fn main() void = test();\n"
 		"export fn main() void = test(void, void, void);\n"
@@ -21,6 +17,22 @@
 		"export fn main() void = void: int as uint: u16 is u8;\n");
 };
 
+@test fn constant() void = {
+	roundtrip("export fn main() void = 2 + -4 + void + true + \"hello\" + '?';\n");
+};
+
+@test fn control() void = {
+	roundtrip("export fn main() void = {
+	break;
+	break :foo;
+	continue;
+	continue :foo;
+	return;
+	return 2 + 2;
+};
+");
+};
+
 @test fn list() void = {
 	roundtrip("export fn main() void = {
 	2 + 2;
diff --git a/hare/parse/expr.ha b/hare/parse/expr.ha
@@ -158,7 +158,21 @@ fn constant(lexer: *lex::lexer) (ast::expr | error) = {
 };
 
 fn control(lexer: *lex::lexer) (ast::expr | error) = {
-	abort(); // TODO
+	let tok = want(lexer, ltok::BREAK, ltok::CONTINUE, ltok::RETURN)?;
+	let label = if (tok.0 == ltok::BREAK || tok.0 == ltok::CONTINUE) {
+		match (try(lexer, ltok::LABEL)?) {
+			tok: lex::token => tok.1 as str,
+			void => "",
+		};
+	} else "";
+	return switch (tok.0) {
+		ltok::BREAK => label: ast::break_expr,
+		ltok::CONTINUE => label: ast::continue_expr,
+		ltok::RETURN => match (peek(lexer, ltok::COMMA, ltok::SEMICOLON)?) {
+			void => alloc(expression(lexer)?): ast::return_expr,
+			lex::token => null: ast::return_expr,
+		},
+	};
 };
 
 fn expression_list(lexer: *lex::lexer) (ast::expr | error) = {
diff --git a/hare/unparse/expr.ha b/hare/unparse/expr.ha
@@ -59,7 +59,15 @@ export fn expr(
 			z;
 		},
 		e: []ast::binding_expr => abort(),
-		e: ast::break_expr => abort(),
+		e: ast::break_expr => {
+			let z = fmt::fprint(out, "break")?;
+			// TODO: https://todo.sr.ht/~sircmpwn/hare/380
+			let l = e: ast::label: str;
+			if (l != "") {
+				z += fmt::fprintf(out, " :{}", l)?;
+			};
+			z;
+		},
 		e: ast::call_expr => {
 			let z = expr(out, indent, *e.lvalue)?;
 			z += fmt::fprintf(out, "(")?;
@@ -87,7 +95,15 @@ export fn expr(
 			z;
 		},
 		e: ast::constant_expr => constant(out, indent, e)?,
-		e: ast::continue_expr => abort(),
+		e: ast::continue_expr => {
+			let z = fmt::fprint(out, "continue")?;
+			// TODO: https://todo.sr.ht/~sircmpwn/hare/380
+			let l = e: ast::label: str;
+			if (l != "") {
+				z += fmt::fprintf(out, " :{}", l)?;
+			};
+			z;
+		},
 		e: ast::defer_expr => abort(),
 		e: ast::delete_expr => abort(),
 		e: ast::for_expr => abort(),
@@ -112,7 +128,17 @@ export fn expr(
 			let z = expr(out, indent, *e)?;
 			z + fmt::fprintf(out, "?")?;
 		},
-		e: ast::return_expr => abort(),
+		e: ast::return_expr => {
+			let z = fmt::fprint(out, "return")?;
+			match (e) {
+				null => void,
+				e: *ast::expr => {
+					z += fmt::fprint(out, " ")?;
+					z += expr(out, indent, *e)?;
+				},
+			};
+			z;
+		},
 		e: ast::slice_expr => {
 			let z = expr(out, indent, *e.object)?;
 			z += fmt::fprint(out, "[")?;