If you are wondering whether use constant is available in versions prior to 5.6.0, it was introduced in 5.004. In fact if you were using the late 5.003 versions (circa 5.003_90+) it was there in betas leading up to 5.004.

Nevertheless, it's been there for a long time, at least as far as scalars go. Constant hashes and arrays didn't work correctly until around 5.005_03.

g r i n d e r