From 62dfeef42d6c2e279165b6dbe73ee3abf98db146 Mon Sep 17 00:00:00 2001
From: Leo Tenenbaum <pommicket@gmail.com>
Date: Tue, 27 Aug 2019 16:02:07 -0400
Subject: basic type inference

---
 cgen.c   |  2 +-
 infer.c  | 32 ++++++++++++++++++++++++++++++++
 out.c    |  2 ++
 parse.c  |  4 +++-
 test.toc |  3 +++
 5 files changed, 41 insertions(+), 2 deletions(-)

diff --git a/cgen.c b/cgen.c
index 222d624..2cb7dcb 100644
--- a/cgen.c
+++ b/cgen.c
@@ -5,7 +5,7 @@ static bool cgen_expr(CGenerator *g, Expression *e) {
 		break;
 	case EXPR_FLOAT_LITERAL:
 		/* TODO: more precision */
-		cgen_write(g, "%f", e->floatl);
+		cgen_write(g, "%f", (double)e->floatl);
 		break;
 	case EXPR_STR_LITERAL:
 		cgen_write(g, "\"");
diff --git a/infer.c b/infer.c
index f4faf07..dad5241 100644
--- a/infer.c
+++ b/infer.c
@@ -1,3 +1,35 @@
+/* if check_curr, this will check against the current value of t */
+static bool infer_expr(Expression *e) {
+	Type *t = &e->type;
+	switch (e->kind) {
+	case EXPR_INT_LITERAL:
+	    t->kind = TYPE_BUILTIN;
+		t->builtin = BUILTIN_I64;
+		break;
+	case EXPR_FLOAT_LITERAL:
+		t->kind = TYPE_BUILTIN;
+		t->builtin = BUILTIN_FLOAT;
+		break;
+	}
+	return true;
+}
+
+static bool type_eq(Type *a, Type *b) {
+	return true; /* TODO */
+}
+	
 static bool infer_decl(Declaration *d) {
+	if (d->flags & DECL_FLAG_FOUND_TYPE) return true;
+	if (!infer_expr(&d->expr)) return false;
+	if (d->flags & DECL_FLAG_INFER_TYPE) {
+		d->type = d->expr.type;
+	} else {
+		if (!type_eq(&d->type, &d->expr.type)) {
+			/* TODO more helpful error */
+			err_print(d->where, "Type mismatch");
+			return false;
+		}
+	}
+	d->flags |= DECL_FLAG_FOUND_TYPE;
 	return true;
 }
diff --git a/out.c b/out.c
index ca6858c..33076c5 100644
--- a/out.c
+++ b/out.c
@@ -7,6 +7,8 @@ void main__(void) {
 	void (*bar)(void) = a___; 
 	foo();
 	a___();
+	int64_t r = 12; 
+	float p = 13.800000; 
 }
 static void foo(void) {
 	void (*x)(void) = a___; 
diff --git a/parse.c b/parse.c
index c4d8588..5b1326b 100644
--- a/parse.c
+++ b/parse.c
@@ -69,7 +69,7 @@ typedef enum {
 			  BINARY_MINUS
 } BinaryOp;
 
-#define EXPR_FLAG_FLEXIBLE 0x01
+#define EXPR_FLAG_FLEXIBLE 0x01	/* e.g. 4 => float/i32/etc. */
 
 typedef struct Expression {
 	Location where;
@@ -101,6 +101,7 @@ typedef struct Expression {
 #define DECL_FLAG_INFER_TYPE 0x01
 #define DECL_FLAG_CONST 0x02
 #define DECL_FLAG_HAS_EXPR 0x04
+#define DECL_FLAG_FOUND_TYPE 0x08
 
 /* OPTIM: Instead of using dynamic arrays, do two passes. */
 typedef struct Declaration {
@@ -446,6 +447,7 @@ static bool parse_expr(Parser *p, Expression *e, Token *end) {
 				e->type.kind = TYPE_BUILTIN;
 				e->type.builtin = BUILTIN_FLOAT;
 				e->floatl = num->floatval;
+				printf("%g\n",(double)e->floatl);
 				break;
 			case NUM_LITERAL_INT:
 				e->kind = EXPR_INT_LITERAL;
diff --git a/test.toc b/test.toc
index 0adc8f2..94c5a84 100644
--- a/test.toc
+++ b/test.toc
@@ -5,4 +5,7 @@ main @= fn() {
 
 	 foo();
 	 bar();
+
+		r := 12;
+		p @= 13.8;
 };
\ No newline at end of file
-- 
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