while loops, comparisons, modulo, fizzbuzz

1 files changed, 34 insertions, 6 deletions

diff --git a/com.c b/com.c
index fef2dab..cfe4df5 100644
--- a/com.c
+++ b/com.c
@@ -83,17 +83,42 @@ static void compile_node(State *S, Chunk *ch, AstNode a) {
 			// B:
 			compile_node(S, ch, l.vals[1]);
 			chunk_wbc(S, ch, OP_0BRANCH);
-			size_t ph1 = placeholder(S, ch);
+			size_t ph_a = placeholder(S, ch);
 			compile_node(S, ch, l.vals[2]);
 			chunk_wbc(S, ch, OP_SKIP);
-			size_t ph2 = placeholder(S, ch);
-			size_t dest1 = ch->bc.len;
+			size_t ph_b = placeholder(S, ch);
+			size_t dest_a = ch->bc.len;
 			compile_node(S, ch, l.vals[3]);
-			size_t dest2 = ch->bc.len;
+			size_t dest_b = ch->bc.len;
 
-			patch(S, ch, ph1, dest1 - ph1 - 2);
-			patch(S, ch, ph2, dest2 - ph2 - 2);
+			patch(S, ch, ph_a, dest_a - ph_a - 2);
+			patch(S, ch, ph_b, dest_b - ph_b - 2);
 
+		} else if (0 == strcmp(name, "while")) { 
+			CK(l.len >= 3, "while requires at least 2 arguments");
+			// (while cond body ...)
+			// A:
+			// cond
+			// 0branch ->B
+			// body ....
+			// redo ->A
+			// B:
+			// nil   (while loop always returns nil)
+			size_t dest_a = ch->bc.len;
+			compile_node(S, ch, l.vals[1]);
+			chunk_wbc(S, ch, OP_0BRANCH);
+			size_t ph_b = placeholder(S, ch);
+			for (int i = 2; i < l.len; i++)  {
+				compile_node(S, ch, l.vals[i]);
+				chunk_wbc(S, ch, OP_DROP);
+			}
+			chunk_wbc(S, ch, OP_REDO);
+			size_t ph_a = placeholder(S, ch);
+			size_t dest_b = ch->bc.len;
+			chunk_wbc(S, ch, OP_NIL);
+
+			patch(S, ch, ph_a, ph_a - dest_a + 2);
+			patch(S, ch, ph_b, dest_b - ph_b - 2);
 
 		} else {
 				
@@ -106,6 +131,9 @@ static void compile_node(State *S, Chunk *ch, AstNode a) {
 				OP('-', OP_SUB)
 				OP('*', OP_MUL)
 				OP('/', OP_DIV)
+				OP('=', OP_EQU)
+				OP('<', OP_CMP)
+				OP('%', OP_MOD)
 			#undef OP
 				default:
 					printf("unkown op %s\n",l.vals[0].as.str);