fixed problems with using _ as an identifier

5 files changed, 45 insertions, 37 deletions

diff --git a/cgen.c b/cgen.c
index f73debd..9fde5a6 100644
--- a/cgen.c
+++ b/cgen.c
@@ -1911,6 +1911,7 @@ static void cgen_decl(CGenerator *g, Declaration *d) {
 		/* declarations where we use a value */
 		for (int idx = 0, nidents = (int)arr_len(d->idents); idx < nidents; ++idx) {
 			Identifier i = d->idents[idx];
+			if (ident_eq_str(i, "_")) continue;
 			Type *type = decl_type_at_index(d, idx);
 			if (type_is_compileonly(&d->type)) {
 				continue;
@@ -1969,6 +1970,7 @@ static void cgen_decl(CGenerator *g, Declaration *d) {
 				
 					arr_foreach(d->idents, Identifier, i) {
 						Expression e;
+						if (ident_eq_str(*i, "_")) continue;
 						e.flags = EXPR_FOUND_TYPE;
 						e.kind = EXPR_IDENT;
 						e.type = d->type;
@@ -1977,13 +1979,18 @@ static void cgen_decl(CGenerator *g, Declaration *d) {
 					}
 					cgen_write(g, "}");
 				} else {
-					/* set it directly */
-					Expression e = {0};
-					e.kind = EXPR_IDENT;
-					e.type = d->type;
-					e.flags = EXPR_FOUND_TYPE;
-					e.ident = d->idents[0];
-					cgen_set(g, &e, NULL, &d->expr, NULL);
+					if (ident_eq_str(d->idents[0], "_")) {
+						cgen_expr(g, &d->expr);
+						cgen_write(g, ";");
+					} else {
+						/* set it directly */
+						Expression e = {0};
+						e.kind = EXPR_IDENT;
+						e.type = d->type;
+						e.flags = EXPR_FOUND_TYPE;
+						e.ident = d->idents[0];
+						cgen_set(g, &e, NULL, &d->expr, NULL);
+					}
 				}
 			}
 		}
diff --git a/main.c b/main.c
index f7d5b02..debaaae 100644
--- a/main.c
+++ b/main.c
@@ -8,13 +8,6 @@
 
 /* 
 @TODO:
-test:
-	_ := 5;
-	_ := 6;
-don't allow use of the identifier _, e.g. puti(_+5) ok for fields i think
-use
- - use with struct members (e.g. SuperPoint ::= struct { use p: Point; })
-maybe change to #define check(x) do { if_unlikely(x) return 0; } while (0);
 always use pointers in cgen'd non-range for loops (sometimes also indices)
 is there a problem where we can get TYPE_UNKNOWN in cgen, triggering an assert(0)?
 	-simple example, but maybe try other stuff: x := #C("5"); 
@@ -25,6 +18,8 @@ allow `use ???;` if an error has already occurred
 if something gets included into a namespace, and its typing fails, the namespace should still be of type namespace, not ???
 make sure you can do a[i] where a is &[5]int or &[]char or something
 do we consistently handle x := &some_array_or_slice; x.len
+use
+ - use with struct members (e.g. SuperPoint ::= struct { use p: Point; })
 &void
 simplify eval macros with val_to_u/i64
 #if should not create a block
diff --git a/misc.c b/misc.c
index 4e82ff8..9b21209 100644
--- a/misc.c
+++ b/misc.c
@@ -77,3 +77,13 @@ static char const *indefinite_article(char const *s) {
 	return "a";
 }
 
+#ifdef __GNUC__
+#define if_likely(x) if (__builtin_expect(x, 1))
+#define if_unlikely(x) if (__builtin_expect(x, 0))
+#else
+#define if_likely if
+#define if_unlikely if
+#endif
+
+#define check(x) do { if_unlikely (!x) return false; } while (0);
+
diff --git a/test.toc b/test.toc
index a30d6ee..ed66392 100644
--- a/test.toc
+++ b/test.toc
@@ -1,28 +1,18 @@
 #include "std/io.toc";
-/*
-sum ::= fn(n::=, t::=, a: [n]t) t {
-	total : t = 0;
-	for x := a {
-		total += x;
-	}
-	total
-}
-
-main ::= fn() {
-	t ::= int;
-	numbers : [1000]t;
-	for x, i : (&t, t) = &numbers {
-		*x = i;
-	}
-	puti(sum(numbers) as int);
 
+foo ::= fn() int {
+	puts("Hello");
+	3
 }
-*/
-Point ::= struct {
-	x, y : int;
+
+bar ::= fn() (int, int) {
+	foo(), foo()
 }
 
 main ::= fn() {
-	p: Point;
-	p.x = 12 + e;
+	_ := 5;
+	_ := 6+_;
+	_ := foo();
+	_,_ := bar();
+	_,_ := bar();
 }
diff --git a/types.c b/types.c
index 6cb6e97..2eb64f0 100644
--- a/types.c
+++ b/types.c
@@ -282,6 +282,7 @@ purpose is something like "take address of"
 */
 static Status expr_must_lval(Expression *e, char const *purpose) {
 	/* NOTE: make sure you update eval when you change this */
+	assert(e->flags & EXPR_FOUND_TYPE);
 	switch (e->kind) {
 	case EXPR_IDENT: {
 		Identifier i = e->ident;
@@ -1942,8 +1943,13 @@ static Status types_expr(Typer *tr, Expression *e) {
 	}
 	case EXPR_IDENT: {
 		Block *b = tr->block;
-		char *i_str = e->ident_str.str;
-		size_t i_len = e->ident_str.len;
+		String i = e->ident_str;
+		char *i_str = i.str;
+		size_t i_len = i.len;
+		if_unlikely (str_eq_cstr(i, "_")) {
+			err_print(e->where, "You cannot use _ as a variable. It is used for ignoring results of function calls, e.g. _, y := function_which_returns_two_things();");
+			return false;
+		}
 		Identifier final_ident = NULL;
 		bool undeclared = true;
 		while (1) { /* for each block we are inside... */