mk

Built by wollf. This program was written by wollf-v7sf3, a 27B model trained to write wolf, driven through opencode by the prompts in prompts/, with a human reviewer judging each phase and writing the next. Every claim below is pasted from the binary; the test script is the reason to trust it.

A make for the plain Makefile subset — targets, prerequisites, recipes, variables, automatic variables, mtime-driven rebuilds, -n, -k, and -j N — refusing everything else by name. If your Makefile has no pattern rules, no include, no ifeq, no functions, mk builds it as GNU make does on the corpus below. test.sh compares mk against GNU make 3.81:

• on 12 corpus directories: the first and the second run, serially and with -j 2, and -n -j 2;
• on their own directories: -k, -s and a command-line variable;
• each comparing the output, the exit status and the files written.

The refusals and usage errors are checked by name.

Install

wolf build main.lu -o mk

Requires wolf 0.2.34 (https://github.com/wolffe-lang/wolf-lang) and a POSIX shell.

Usage

Usage: mk [-f FILE] [-C DIR] [-n] [-s] [-k] [-j [N]] [-p] [NAME=VALUE]... [GOAL]...
       mk --help
       mk --version

  -p         print the parsed database (variables sorted, rules in file order)
  -n         print recipes without running them
  -s         silent mode (do not print recipes)
  -k         keep going after a failure
  -j [N]     allow up to N jobs at once; no N: no limit
  -f FILE    read FILE as the Makefile
  -C DIR     change to DIR before doing anything
  --version  print the version and exit
  NAME=VALUE set a variable from the command line

The subset

Accepted

Refused (exit 2, one line on stderr naming the construct)

Out-of-date rule

A target is out of date when:

1. It does not exist, or
2. Any prerequisite is newer (mtime strictly greater), or
3. Any prerequisite was rebuilt in this run, or
4. The target is .PHONY

A prerequisite with no rule that does not exist is an error: mk: *** No rule to make target `missing_file', needed by `result'. Stop.

-j and -k semantics

• -j N runs up to N recipes simultaneously. A target starts only after all its prerequisites are done. The order of starts is the discovery order from a depth-first walk, so -j 1 produces exactly GNU make's serial order.
• -k keeps building targets that do not depend on a failed one. The exit status is 2.

Exit codes

• 0 — up to date or built successfully
• 2 — any error (GNU's convention)

Tests

wolf build main.lu -o mk
wolf test .              # 42 unit tests
./test.sh                # 94 corpus rows against GNU make
wolf fmt --check *.lu

test.sh runs each corpus directory in a fresh mktemp -d copy, comparing mk against GNU make on the same Makefile. A row passes when the two tools agree on the observable behaviour (output, exit status and the files written). The oracle is GNU make beside it.

The 94 rows cover 12 directories across 19 test kinds: N1 (dry-run output), B1 (files after build), B2 (second run), B3 (build from a subset), F1 (failure with -k), M1 (missing target), C1 (cycle), J1 (wide build), J2 (diamond with -j), R1 (refusals), P1 (print database), J3 (parallel), U1/U2 (second-run comparison), D1 (dry-run with -j), K1 (keep-going), S1 (silent), V1 (command-line variables), RJ (refusals under -j), and E1 (usage errors).

Measured numbers

Machine: Apple M5 Pro, macOS, wolf 0.2.34. Date: 2026-10-23.

Files