Andy Wingo <wi...@pobox.com> writes:
> On Sun 26 Jun 2016 23:06, Andy Wingo <wi...@pobox.com> writes:
>
>> On Tue 17 Nov 2015 09:27, Koz Ross <koz.r...@retro-freedom.nz> writes:
>>
>>> I have the following file, called foo.scm:
>>>
>>> (define-module (koz foo)
>>> #:use-module (srfi srfi-9))
>>>
>>> (define-public (make-empty-bar)
>>> (make-bar #f))
>>>
>>> (define-record-type <bar>
>>> (make-bar open)
>>> bar?
>>> (open bar-open set-bar-open!))
>>
>>> Would it be possible for the error message in this case to be a bit
>>> more helpful? Even better, would it be possible to not make this an
>>> issue when compiling?
>>
>> It would be possible to make the scope of make-bar be the whole file.
>> In theory it should work I guess, given this news entry from 2.0.1:
>>
>> ** `begin' expands macros in its body before other expressions
>
> Apparently the reason this doesn't work in Guile right now is that the
> compiler currently reads and compiles one Scheme expression at a time,
> then stitches them together on the Tree-IL level. Incidentally,
> `primitive-load' works in the same way for the interpreter: it reads and
> eval's single expressions in a loop. We could change this to have Guile
> read the whole file and pass it all to the expander at once, within a
> `begin'. This has some user-visible changes though:
>
> * if evaluating an expression throws an error, primitive-load doesn't
> read the following expressions and so doesn't detect syntax errors;
> try a file like this:
>
> (error "what")
> )
>
> With the interpreter (primitive-load) you will get the "what" error,
> not a syntax error. (Yes the unclosed paren hurts my eyeballs but I
> wanted to demonstrate a syntax error. Here's a matching paren:
> ")".)
>
> * Procedural macros won't be able to use bindings defined previously
> in the file unless they are eval-whenned. Of course this already
> breaks in the compiler, but it succeeds in the interpreter.
Another problem is that in several places, we assume that if a top-level
form calls 'set-current-module', the forms that follow in the file will
now be expanded within that new module. This behavior is needed for
'define-module' to work properly, and it's also assumed in boot-9.scm,
psyntax-pp.scm, and maybe some other places.
Mark
