initial commit of branch

1 files changed, 38 insertions, 0 deletions

diff --git a/compiler.d b/compiler.d
index 675ec4c..8cb65ee 100644
--- a/compiler.d
+++ b/compiler.d
@@ -83,6 +83,41 @@ class Compiler {
         }
     }
 
+    void compileBranch(Form form) {
+
+        Branch branch = cast(Branch)form;
+
+        Cons clause;
+        int[] endJumps;
+        int currentJump;
+        foreach (Form cl ; branch.clauses) {
+            // resolve the condition
+            clause = cast(Cons)cl;
+            this.resolve(clause.head);
+            this.func.chunk.writeOp(OpCode.OP_TYPE_CHECK_BOOLEAN, clause.line);
+
+            // write a jump spot and pop
+            currentJump = this.jump(OpCode.OP_JUMP_IF_FALSE);
+            this.func.chunk.writeOp(OpCode.OP_POP, clause.line);
+
+            // resolve the result of the condition (only executes if true)
+            foreach (Form f ; clause.tail) {
+                this.resolve(f);
+            }
+
+            // jump to the end (if we got here)
+            endJumps ~= this.jump(OpCode.OP_JUMP);
+
+            // this is where we jump to if the condition was false
+            this.patchJump(currentJump);
+        }
+
+        // patch all the end jumps
+        foreach (int jmp; endJumps) {
+            this.patchJump(jmp);
+        }
+    }
+
     void compileIf(Form form) {
         If if_ = cast(If)form;
 
@@ -908,6 +943,9 @@ class Compiler {
             case FormType.IF:
                 this.compileIf(form);
                 break;
+            case FormType.BRANCH:
+                this.compileBranch(form);
+                break;
             case FormType.AND:
                 this.compileAnd(form);
                 break;