--print-format currently uses printf-style format strings, which have
limited namespace (a-zA-Z), low flexibility (depends-with-version and
depends-without-version have to be different sequences), and are
difficult to remember (is %d depends or description?).
Python/Rust format strings allow full word substitutions. In addition,
the mfmt.c library being used makes it possible to extend the standard
formatting for much greater control. For example, we can allow nested
templates so that instead of having "{depends}" and
"{depends-without-version}" variants, we can allow something like
"{depends<{name}={version}: {description}>}".
For example:
pacman -Sp --pformat="{name}: {description} ({packager})" pacman
