prevented variables from being captured

4 files changed, 38 insertions, 10 deletions

diff --git a/main.c b/main.c
index d94fcaf..a963d0c 100644
--- a/main.c
+++ b/main.c
@@ -1,6 +1,5 @@
 /* 
 TODO:
-allow void block expression statements not to have semicolons
 don't allow nested functions to capture outer variables (constants are allowed though)
 if, else
 re-do cgen
diff --git a/parse.c b/parse.c
index 8f55c17..e0f6cdc 100644
--- a/parse.c
+++ b/parse.c
@@ -49,10 +49,17 @@ typedef struct Type {
 	};
 } Type;
 
+typedef enum {
+			  BLOCK_FN,
+			  BLOCK_EXPR
+} BlockKind;
+
 typedef struct Block {
+	BlockKind kind;
 	Location start;
 	Location end;
 	Array stmts;
+	struct Block *parent;
     struct Expression *ret_expr; /* the return expression of this block, e.g. {foo(); 3} => 3  NULL for no expression. */
 } Block;
 
@@ -555,6 +562,7 @@ static bool parse_stmt(Parser *p, Statement *s);
 static bool parse_block(Parser *p, Block *b) {
 	Tokenizer *t = p->tokr;
 	Block *prev_block = p->block;
+	b->parent = prev_block;
 	p->block = b;
 	if (!token_is_kw(t->token, KW_LBRACE)) {
 		tokr_err(t, "Expected '{' to open block.");
@@ -566,7 +574,7 @@ static bool parse_block(Parser *p, Block *b) {
 	bool ret = true;
 	b->ret_expr = NULL; /* default to no return unless overwritten later */
 	if (!token_is_kw(t->token, KW_RBRACE)) {
-		/* non-empty function body */
+		/* non-empty block */
 		while (1) {
 			Statement *stmt = arr_add(&b->stmts);
 			bool success = parse_stmt(p, stmt);
@@ -629,6 +637,7 @@ static bool parse_fn_expr(Parser *p, FnExpr *f) {
 			return false;
 		}
 	}
+	f->body.kind = BLOCK_FN;
 	return parse_block(p, &f->body);
 }
 
@@ -918,6 +927,7 @@ static bool parse_expr(Parser *p, Expression *e, Token *end) {
 		if (token_is_kw(t->token, KW_LBRACE)) {
 			/* it's a block */
 			e->kind = EXPR_BLOCK;
+			e->block.kind = BLOCK_EXPR;
 			if (!parse_block(p, &e->block)) return false;
 			if (t->token != end) {
 				tokr_err(t, "Expression continues after end of block."); /* TODO: improve this err message */
diff --git a/test.toc b/test.toc
index 82666ee..720c87e 100644
--- a/test.toc
+++ b/test.toc
@@ -1,7 +1,12 @@
+x := 3;
+
 main @= fn() {
-	 f := main;
-	 f();
-	 { main(); }
-	 f();
+	 y := 5;
+	 z @= 10;
+	 foo @= fn() {
+	 	 bar := y;
+		 asdf := z;
+		 gfdij := x;
+	 };
 };
 
diff --git a/types.c b/types.c
index f5804bc..472401d 100644
--- a/types.c
+++ b/types.c
@@ -1,5 +1,6 @@
 typedef struct {
 	Array in_decls;	/* array of declarations we are currently inside */
+	Block *block;
 } Typer;
 
 static bool type_of_expr(Typer *tr, Expression *e);
@@ -128,10 +129,7 @@ static bool expr_must_lval(Expression *e) {
 	switch (e->kind) {
 	case EXPR_IDENT: {
 		IdentDecl *id_decl = ident_decl(e->ident);
-		if (!id_decl) {
-			err_print(e->where, "Undeclared identifier.");
-			return false;
-		}
+		assert(id_decl);
 		Declaration *d = id_decl->decl;
 		if (d->flags & DECL_FLAG_CONST) {
 			char *istr = ident_to_str(e->ident);
@@ -163,6 +161,18 @@ static bool type_of_ident(Typer *tr, Location where, Identifier i, Type *t, bool
 		return false;
 	}
 	Declaration *d = decl->decl;
+	bool captured = false;
+	if (decl->scope != NULL)
+		for (Block *block = tr->block; block != decl->scope; block = block->parent) {
+			if (block->kind == BLOCK_FN) {
+				captured = true;
+				break;
+			}
+		}
+	if (captured && !(d->flags & DECL_FLAG_CONST)) {
+		err_print(where, "Variables cannot be captured into inner functions (but constants can).");
+		return false;
+	}
 	/* are we inside this declaration? */
 	typedef Declaration *DeclarationPtr;
 	arr_foreach(&tr->in_decls, DeclarationPtr, in_decl) {
@@ -504,6 +514,8 @@ static bool type_of_expr(Typer *tr, Expression *e) {
 
 static bool types_block(Typer *tr, Block *b) {
 	bool ret = true;
+	Block *prev_block = tr->block;
+	tr->block = b;
 	if (!block_enter(b, &b->stmts)) return false;
 	arr_foreach(&b->stmts, Statement, s) {
 		if (!types_stmt(tr, s)) ret = false;
@@ -512,6 +524,7 @@ static bool types_block(Typer *tr, Block *b) {
 		if (!types_expr(tr, b->ret_expr))
 			ret = false;
 	block_exit(b, &b->stmts);
+	tr->block = prev_block;
 	return ret;
 }
 
@@ -617,6 +630,7 @@ static bool types_stmt(Typer *tr, Statement *s) {
 }
 
 static void typer_create(Typer *tr) {
+	tr->block = NULL;
 	arr_create(&tr->in_decls, sizeof(Declaration *));
 }