Add initial IF implementation

1 files changed, 66 insertions, 0 deletions

diff --git a/src/bytecode/compiler.h b/src/bytecode/compiler.h
index b1cdfb9..559ad1c 100755
--- a/src/bytecode/compiler.h
+++ b/src/bytecode/compiler.h
@@ -232,6 +232,71 @@ compile_declare_op(Chunk *chunk, Visitor *vs, Token start, Ops op) {
 }
 
 void
+compile_if_op(Chunk *chunk, Visitor *vs, Token start) {
+    Token tok = peek_token(vs);
+    if (tok.type == TOKEN_EOF) {
+        error_push((Error){
+            .type = ERR_TYPE_COMPILER,
+            .value = ERR_UNBALANCED_PAREN,
+            .line = start.line,
+            .col = start.column,
+        });
+        return;
+    }
+    if (tok.type == TOKEN_RPAREN) {
+        error_push((Error){
+            .type = ERR_TYPE_COMPILER,
+            .value = ERR_NOT_ENOUGH_ARGS,
+            .line = start.line,
+            .col = start.column,
+        });
+        return;
+    }
+
+    // Condition.
+    parse_tree(chunk, vs);
+    emit_constant(chunk, tok, FIXNUM_VAL(0xFF));
+    size_t pos = array_size(chunk->code);
+    add_code(chunk, OP_JUMP_IF_FALSE, start.line, start.column);
+
+    // Block true.
+    parse_tree(chunk, vs);
+
+    // No else.
+    if (peek_token(vs).type == TOKEN_RPAREN) {
+        size_t false_block_start = array_size(chunk->code) - pos - 1;
+        size_t num_idx = add_constant(chunk, FIXNUM_VAL(false_block_start));
+        chunk->code[pos - 1] = num_idx;
+        next_token(vs);
+        return;
+    }
+
+    // Else.
+    emit_constant(chunk, tok, FIXNUM_VAL(0xFF));
+    size_t else_pos = array_size(chunk->code);
+    add_code(chunk, OP_JUMP, start.line, start.column);
+
+    size_t false_block_start = array_size(chunk->code) - pos - 1;
+    size_t num_idx = add_constant(chunk, FIXNUM_VAL(false_block_start));
+    chunk->code[pos - 1] = num_idx;
+    parse_tree(chunk, vs);
+    false_block_start = array_size(chunk->code) - else_pos - 1;
+    num_idx = add_constant(chunk, FIXNUM_VAL(false_block_start));
+    chunk->code[else_pos - 1] = num_idx;
+
+    if (peek_token(vs).type != TOKEN_RPAREN) {
+        error_push((Error){
+            .type = ERR_TYPE_COMPILER,
+            .value = ERR_TOO_MANY_ARGS,
+            .line = start.line,
+            .col = start.column,
+        });
+        return;
+    }
+    next_token(vs);
+}
+
+void
 parse_list(Chunk *chunk, Visitor *vs, Token start) {
     if (!has_next_token(vs)) {
         error_push((Error){
@@ -262,6 +327,7 @@ parse_list(Chunk *chunk, Visitor *vs, Token start) {
         case TOKEN_NEWLINE: { compile_list_simple_op(chunk, vs, start, OP_NEWLINE); } break;
         case TOKEN_DEF: { compile_declare_op(chunk, vs, start, OP_DEF); } break;
         case TOKEN_SET: { compile_declare_op(chunk, vs, start, OP_SET); } break;
+        case TOKEN_IF: { compile_if_op(chunk, vs, start); } break;
         default: {
             error_push((Error){
                 .type = ERR_TYPE_COMPILER,