hare

commit 24c7a700cc30f1a9fa27d82483efc5a5585d9607
parent 2621ec2fcb906c4363a4f750b6b5ca5248ff0997
Author: Drew DeVault <sir@cmpwn.com>
Date:   Thu, 15 Apr 2021 11:53:15 -0400

hare::parse: parse constant expressions

Diffstat:
M
hare/ast/expr.ha
 | 
5
++++-
M
hare/parse/+test/expr.ha
 | 
4
++++
M
hare/parse/expr.ha
 | 
29
++++++++++++++++++++++++++---
M
hare/unparse/expr.ha
 | 
26
+++++++++++++++++++++-----

4 files changed, 55 insertions(+), 9 deletions(-)
diff --git a/hare/ast/expr.ha b/hare/ast/expr.ha
@@ -137,8 +137,11 @@ export type struct_constant = struct {
 // (foo, bar, ...)
 export type tuple_constant = []*expr;
 
+// The value "null".
+export type _null = void;
+
 // A constant
-export type constant_expr = (void | lex::value | array_constant |
+export type constant_expr = (void | bool | _null | lex::value | array_constant |
 	struct_constant | tuple_constant);
 
 // continue :label
diff --git a/hare/parse/+test/expr.ha b/hare/parse/+test/expr.ha
@@ -2,6 +2,10 @@
 	roundtrip("export fn main() void = void + void * void / void;\n");
 };
 
+@test fn constant() void = {
+	roundtrip("export fn main() void = 2 + -4 + void + true;\n");
+};
+
 @test fn cast() void = {
 	roundtrip("export fn main() void = void: int;\n"
 		"export fn main() void = void as int;\n"
diff --git a/hare/parse/expr.ha b/hare/parse/expr.ha
@@ -65,8 +65,31 @@ fn cast(lexer: *lex::lexer, lvalue: (ast::expr | void)) (ast::expr | error) = {
 };
 
 fn constant(lexer: *lex::lexer) (ast::expr | error) = {
-	want(lexer, ltok::VOID)?;
-	return void;
+	let tok = want(lexer)?;
+	return switch (tok.0) {
+		ltok::LIT_U8,
+		ltok::LIT_U16,
+		ltok::LIT_U32,
+		ltok::LIT_U64,
+		ltok::LIT_UINT,
+		ltok::LIT_SIZE,
+		ltok::LIT_I8,
+		ltok::LIT_I16,
+		ltok::LIT_I32,
+		ltok::LIT_I64,
+		ltok::LIT_INT,
+		ltok::LIT_ICONST,
+		ltok::LIT_F32,
+		ltok::LIT_F64,
+		ltok::LIT_FCONST,
+		ltok::LIT_RUNE,
+		ltok::LIT_STR => tok.1,
+		ltok::VOID => void,
+		ltok::TRUE => true,
+		ltok::FALSE => false,
+		ltok::NULL => ast::_null,
+		* => syntaxerr(mkloc(lexer), "Expected constant expression"),
+	};
 };
 
 fn control_statement(lexer: *lex::lexer) (ast::expr | error) = {
@@ -79,7 +102,7 @@ fn objsel(lexer: *lex::lexer) (ast::expr | error) = {
 
 fn plain_expression(lexer: *lex::lexer) (ast::expr | error) = {
 	let tok = peek(lexer)? as lex::token;
-	if (tok.0 > ltok::LAST_BTOK && tok.0 >= ltok::LAST_LITERAL) {
+	if (tok.0 >= ltok::LIT_U8 && tok.0 <= ltok::LAST_LITERAL) {
 		return constant(lexer);
 	};
 	return switch (tok.0) {
diff --git a/hare/unparse/expr.ha b/hare/unparse/expr.ha
@@ -1,8 +1,8 @@
 use io;
 use fmt;
 use hare::ast;
+use hare::lex;
 
-// TODO
 export fn expr(
 	out: *io::stream,
 	indent: size,
@@ -54,10 +54,7 @@ export fn expr(
 			z += _type(out, indent, *e._type)?;
 			z;
 		},
-		e: ast::constant_expr => {
-			assert(e is void);
-			fmt::fprint(out, "void")?;
-		},
+		e: ast::constant_expr => constant(out, indent, e)?,
 		e: ast::continue_expr => abort(),
 		e: ast::defer_expr => abort(),
 		e: ast::delete_expr => abort(),
@@ -87,3 +84,22 @@ export fn expr(
 		},
 	};
 };
+
+fn constant(
+	out: *io::stream,
+	indent: size,
+	e: ast::constant_expr,
+) (size | io::error) = {
+	return match (e) {
+		void => fmt::fprint(out, "void"),
+		ast::_null => fmt::fprint(out, "null"),
+		b: bool => fmt::fprint(out, b),
+		v: lex::value => fmt::fprint(out, match (v) {
+			v: (str | rune | i64 | u64 | f64) => v,
+			void => abort(),
+		}),
+		ast::array_constant => abort(), // TODO
+		ast::struct_constant => abort(), // TODO
+		ast::tuple_constant => abort(), // TODO
+	};
+};