I will note that paying attention to those warnings is super heolpful in programming in guile. I miss these warnings alot when doing python programming.In a sense with these warnings you get close to static typechecking programming languages and scheme/guile is really a nice mix of dynamic and static typing
On Thu, Jan 21, 2021 at 2:58 PM Ricardo Wurmus <rek...@elephly.net> wrote: > > Hi, > > > Consider this bit of simple code: > > > > #+BEGIN_SRC scheme > > > > (define (thunk) > > (lambda (x) > > x)) > > > > (thunk) ;; works ok, I guess. > > (thunk "hello world!\n") ;; runtime error > > > > ;;; <stdin>:1074:0: warning: possibly wrong number of arguments to > `thunk' > > ice-9/boot-9.scm:1669:16: In procedure raise-exception: > > Wrong number of arguments to #<procedure thunk ()> > > > > Entering a new prompt. Type `,bt' for a backtrace or `,q' to continue. > > #+END_SRC > > > > Guile will compile this program seemingly with no error. Guile will > > correctly report at runtime that procedure '(thunk "hello world!\n")' > > takes no arguments, but it's lambda accepts 1 argument. Would it be > > possible to report this error at compile time? Would that be > > advantageous? > > This is not a bug. What you call “thunk” here is a procedure that > returns a procedure. That’s very common and is often done to delay > evaluation. > > It is in fact an error to call the procedure “thunk” with an argument. > It doesn’t matter that it happens to return a procedure that *can* take > an argument. The procedure it returns is just like any other value, > though, and isn’t inspected any further. > > That said, it is not true that Guile will compile this without a > complaint. I dumped your code snippet in a file foo.scm and > compiled it: > > --8<---------------cut here---------------start------------->8--- > guild compile foo.scm > foo.scm:6:0: warning: wrong number of arguments to `thunk' > wrote > `/home/rekado/.cache/guile/ccache/3.0-LE-8-4.4/home/rekado/dev/gx/gwl/foo.scm.go' > --8<---------------cut here---------------end--------------->8--- > > Isn’t that exactly what you’re asking for? > > -- > Ricardo > > > >
