feat(rc): keywords now recognized. for and while loop

Prototypes for loops sketched. This required recognizing keywords and
returning from yylex. Debugging/testing will be required.

1 files changed, 37 insertions, 0 deletions

diff --git a/sys/cmd/rc/code.c b/sys/cmd/rc/code.c
index 0723279..786f284 100644
--- a/sys/cmd/rc/code.c
+++ b/sys/cmd/rc/code.c
@@ -163,6 +163,43 @@ walk(Tree *node)
         }
         node = n;
         break;
+    /* control structures */
+    case Twhile:
+        addr1 = interpreter.i; // head of loop
+        walk(node->child[0]);
+        if(addr1 == interpreter.i)
+            fatal("TODO");
+        emitf(Xtrue);
+        addr2 = emiti(0); // goto end of loop
+
+        walk(node->child[1]);
+        emitf(Xgoto);
+        emiti(addr1);   // goto top of loop
+        storepc(addr2);
+        break;
+
+    case Tfor:
+        emitf(Xmark);
+        if(node->child[1]){ // for( x in X )
+            walk(node->child[1]);
+            // emitf(Xglob)
+        }else{              // for(X)
+            fatal("TODO");
+        }
+        emitf(Xmark); // null initial value for Xlocal
+        emitf(Xmark);
+        walk(node->child[0]);
+        emitf(Xlocal);
+
+        addr1 = emitf(Xfor);
+        addr2 = emiti(0);
+
+        walk(node->child[2]);
+        emitf(Xgoto);
+        emiti(addr1);
+        storepc(addr2);
+        emitf(Xunlocal);
+        break;
 
     /* forks */
     case '&':