mwasm

A WASM binary inspector written in Mere and compiled to a native binary (mere -c | clang).

$ mwasm module.wasm
wasm module: module.wasm (5322 bytes, version 1)
  section 1 (type): 51 bytes
  section 2 (import): 153 bytes
  ...
  section 7 (export): 59 bytes
    exports (4):
      memory memory -> 0
      func main -> 71
  section 10 (code): 4841 bytes

It checks the \0asm magic + version, lists every section (id, name, size), and expands the export section (name, kind, index). Output matches wasm-objdump -h/-x.

Why this exists — and the meta bit

mwasm is a dogfood app for Mere, chosen to attack binary handling: a .wasm file starts with a NUL byte, exactly what C strings choke on. Building it motivated Mere's file_size builtin (v0.1.21) — see PAIN.md.

The meta part: Mere's own compiler emits WebAssembly (mere -w), so mwasm reads the binaries Mere produces:

mere -w prog.mere | wat2wasm --enable-tail-call - -o prog.wasm
mwasm prog.wasm

Notes: LEB128 sizes are decoded with plain arithmetic (% 128, >= 128) — Mere has no bitwise operators and needed none. All byte access is NUL-safe via char_at / ord, so str doubles as a byte buffer here.

Build

mere -c main.mere > m.c && clang -O2 m.c -o mwasm

Roadmap

• M0: magic + version
• M1: section listing (id, name, LEB128 size)
• M2: export section contents (name, kind, index)
• M3: import section / function-count summary (maybe)