Unit 1 — From Stage 0 to a library

Objectives

Reproduce add(20, 22) == 42. Separate a row in the evidence ledger from a hope about the next machine.

Why

Stage 0 is a single function. The later stages are a library only if that function still passes and new claims have their own rows.

Model

ledger row  ->  a command that was run
stage file  ->  what that command is allowed to mean
PENDING     ->  the workflow exists and this commit has not produced the log

Theory

Mojoler.POC.add/2 is still the contract: signed 64-bit addition, ArgumentError on overflow and on a term enif_get_long rejects. experiments/stage0/poc_direct.mojo is the file from before the structs moved into the generated ABI. The live native/poc.mojo imports that ABI. Both have to agree on 42.

E18 and E19 are the Linux CPU proof for that function at commit e6728ea. They are not a proof of the Mix compiler or the GPU batch.

Lab

scripts/doctor.sh
mix test test/poc_test.exs

Expected

Doctor prints the pinned OTP, Elixir, and Mojo, then doctor: ready. ExUnit reports the POC tests passed, including a fresh OS process.

Code

lib/mojoler/poc.ex calls :erlang.load_nif in Mojoler.POC, not in a helper. OTP checks the calling module against ErlNifEntry.name. A helper that calls load_nif itself loads as Elixir.Mojoler.Nif and the VM rejects the library.

Failure

If doctor stops, the rest of the curriculum will not load. If add raises UndefinedFunctionError, @on_load failed. Read the warning above the crash. The usual cause is a module-name mismatch or a missing .so.

Exercise

Find the ledger row that says Linux ldd did not list libKGENCompilerRTShared.

Answer

E19. The red run before it printed libc.so.6 and the dynamic linker only. Darwin still lists KGEN (E11).