compiler now compiles some things

src/debug.c

@@ -0,0 +1,81 @@
+#include <stdio.h>
+
+#include "debug.h"
+#include "print.h"
+#include "vm.h"
+
+static I decode_sleb128(U8 *ptr, Z *bytes_read) {
+  I result = 0;
+  I shift = 0;
+  U8 byte;
+  Z count = 0;
+  do {
+    byte = ptr[count++];
+    result |= (I)(byte & 0x7F) << shift;
+    shift += 7;
+  } while (byte & 0x80);
+  if ((shift < 64) && (byte & 0x40))
+    result |= -(1LL << shift);
+  *bytes_read = count;
+  return result;
+}
+
+V disassemble(Bc *chunk, const char *name) {
+  printf("=== %s ===\n", name);
+  Z offset = 0;
+  while (offset < chunk->count) {
+    offset = disassemble_instruction(chunk, offset);
+  }
+}
+
+Z disassemble_instruction(Bc *chunk, Z offset) {
+  printf("%04zu ", offset);
+  U8 opcode = chunk->items[offset++];
+  switch (opcode) {
+  case OP_NOP:
+    printf("NOP\n");
+    return offset;
+  case OP_CONST: {
+    Z bytes_read;
+    I idx = decode_sleb128(&chunk->items[offset], &bytes_read);
+    printf("CONST %ld", idx);
+    if (idx >= 0 && idx < (I)chunk->constants.count) {
+      printf(" (");
+      print(chunk->constants.items[idx]);
+      printf(")");
+    }
+    printf("\n");
+    return offset + bytes_read;
+  }
+  case OP_JUMP: {
+    Z bytes_read;
+    I ofs = decode_sleb128(&chunk->items[offset], &bytes_read);
+    printf("JUMP %ld -> %zu\n", ofs, offset + bytes_read + ofs);
+    return offset + bytes_read;
+  }
+  case OP_JUMP_IF_NIL: {
+    Z bytes_read;
+    I ofs = decode_sleb128(&chunk->items[offset], &bytes_read);
+    printf("JUMP_IF_NIL %ld -> %zu\n", ofs, offset + bytes_read + ofs);
+    return offset + bytes_read;
+  }
+  case OP_CALL: {
+    Z bytes_read;
+    I ofs = decode_sleb128(&chunk->items[offset], &bytes_read);
+    printf("CALL %ld\n", ofs);
+    return offset + bytes_read;
+  }
+  case OP_APPLY:
+    printf("APPLY\n");
+    return offset;
+  case OP_RETURN:
+    printf("RETURN\n");
+    return offset;
+  case OP_ADD:
+    printf("ADD\n");
+    return offset;
+  default:
+    printf("? (%d)\n", opcode);
+    return offset;
+  }
+}