Re: compile-time processing of REQUIRE

[smh@EMS.MEDIA.MIT.EDU (Steven Haflich)]

The problem is only partly one of underspecification.  Depending
whether the required file contains only macros, both macros and
execution-time functions, or just execution-time functions, typically
you will want REQUIRE to happen at compile/eval, compile/load/eval, or
load/eval times.

Regardless when a naked REQUIRE does or doesn't happen, you can get
explicit control by surrounding it with an EVAL-WHEN.  This will
protect somewhat from differences between implementations.