From 3dd6b03ff5dc54ad38627e468dd4eb93dddf470f Mon Sep 17 00:00:00 2001
From: Leo Tenenbaum <pommicket@gmail.com>
Date: Fri, 8 May 2020 23:57:39 -0400
Subject: allow use of global variables at compile time

---
 test.toc | 16 ++++++++++++++++
 types.c  | 22 +++++++++++++++++++++-
 types.h  |  8 ++++++--
 3 files changed, 43 insertions(+), 3 deletions(-)

diff --git a/test.toc b/test.toc
index c90b3ce..f989ecf 100644
--- a/test.toc
+++ b/test.toc
@@ -1,6 +1,22 @@
+/*
+
 #include "std/io.toc", io;
 
+
+
 main ::= fn() {
 	io.file_writes(&io.std_out, "hello!\n");
 	io.file_flush(&io.std_out);
 }
+
+*/
+
+
+#include "tests/std/io.toc", io;
+a, b := 5;
+main ::= fn() {
+	a = 6;
+	io.puti(a);
+	io.puti(b);
+}
+main();
diff --git a/types.c b/types.c
index b6a3f5c..789d95f 100644
--- a/types.c
+++ b/types.c
@@ -3417,6 +3417,9 @@ static Status types_decl(Typer *tr, Declaration *d) {
 			goto ret;
 		}
 	}
+	
+	size_t n_idents; n_idents = arr_len(d->idents);
+
 	if (d->flags & DECL_HAS_EXPR) {
 		if (!types_expr(tr, &d->expr)) {
 			success = false;
@@ -3452,11 +3455,28 @@ static Status types_decl(Typer *tr, Declaration *d) {
 				}
 				copy_val(tr->allocr, &d->val, val, dtype);
 				d->flags |= DECL_FOUND_VAL;
+				if (!(d->flags & DECL_IS_CONST)) {
+					/* 
+						create a value stack for this declaration so that it can be modified by compile time execution,
+						but not permanently (i.e. output will still have old value)
+					*/
+
+					Value *copy = typer_malloc(tr, sizeof *copy);
+					if (n_idents > 1 && dtype->kind != TYPE_TUPLE) {
+						/* actually, make n_idents copies of the value, and put them in a tuple. */
+						Value *tuple = copy->tuple = typer_malloc(tr, n_idents * sizeof *copy);
+						for (size_t i = 0; i < n_idents; ++i) {
+							copy_val(tr->allocr, &tuple[i], val, dtype);
+						}
+					} else {
+						copy_val(tr->allocr, copy, val, dtype);
+					}
+					typer_arr_add(tr, d->val_stack, copy);
+				}
 			}
 		}
 	}
 
-	size_t n_idents; n_idents = arr_len(d->idents);
 
 	if (type_is_compileonly(dtype)) {
 		if (!(d->flags & DECL_IS_CONST)) {
diff --git a/types.h b/types.h
index 8d68ab7..50983a2 100644
--- a/types.h
+++ b/types.h
@@ -882,8 +882,12 @@ typedef struct Declaration {
 	};
 	Value val; /* only for constant decls, non-constant globals, and varargs. */
 
-	/* for eval, for non-constant local decls: */
-	/* the pointers to values need to be fixed, which is why this isn't just Value *.  */
+	/* 
+		for eval, for non-constant local decls
+		the pointers to values need to be fixed, which is why this isn't just Value *.
+		no, this can't be a union with val, because of global variables and possibly
+		other things (varargs maybe?)
+	*/
 	Value **val_stack;
 } Declaration;
 typedef Declaration *DeclarationPtr;
-- 
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