chickadee » semantic-version » version-pred!

version-pred! VER #!optional AMT IDX SEARCH?procedure

Return VER with the target element at, or before with SEARCH?, IDX replaced by the AMT predecessor.

semantic-version ; version to adjust.
fixnum ; amount to adjust, default is 1.
fixnum ; which element to adjust, default is (sub1 (version-depth VER)).
boolean ; search backwards for a successful operation from IDX, default is #f.

Only integer elements may be targets. See Notes.

Underflow of a zero predecessor is an error. Overflow of a most-positive-fixnum successor is an error.