Macro processing language
https://www.gnu.org/software/m4 This formula is keg-only.

Current version

m4 requires the following formula to be installed:
xz 5.2.3 General-purpose data compression with high compression ratio

Reverse dependencies

The following formula requires m4 to be installed:
crosstool-ng 1.23.0_1 Tool for building toolchains

Recent formula history

JCount m4: %n crash fix for 10.13
ilovezfs m4: swap GNU url and mirror.
Mike McQuaid m4: import homebrew/dupes into core.

Formula code at GitHub