By default, Gauche reads toplevel Scheme forms one at a time, compile it immediately to intermediate form and execute it on the VM. As long as you use Gauche interactively, it looks like an interpreter. (There’s an experimental ahead-of-time compiler as well. See HOWTO-precompile.txt if you want to give a try.)
The fact that we have separate compilation/execution phase, even interleaved, may lead a subtle surprise if you think Gauche as an interpreter. Here’s a few points to keep in mind:
load is a procedure in Gauche, therefore evaluated at run time.
If the loaded program defines a macro, which is available for the compiler
after the toplevel form containing
load is evaluated. So, suppose
foo.scm defines a macro
foo, and you use the macro
;; in “foo.scm” (define-syntax foo (syntax-rules () ((_ arg) (quote arg)))) ;; in your program (begin (load "foo") (foo (1 2 3))) ⇒ error, bad procedure: ‘1’ (load "foo") (foo (1 2 3)) ⇒ '(1 2 3)
(begin (load ...)) form fails, because the compiler
foo is a special form at the compilation time
(1 2 3) as if it is a normal procedure call.
The latter example works, however, since the execution
of the toplevel form
(load "foo") is done before
(foo (1 2 3)) is compiled.
To avoid this kind of subtleties, use
to load a program fragments. Those are recognized by the compiler.
On the other hand, since
use is recognized
by the compiler, the specified file is loaded even if the form
is in the conditional expression. If you really need to load
a file on certain condition, use
load or do dispatch in macro
cond-expand form (see Feature conditional).)