Re: Guile top-level functions

[Neil Jerram]

Kevin Ryde wrote:
> Neil Jerram <address@hidden> writes:
>
> > - procedure-source may return a new unmemoized copy of the procedure's 
> > source, not the original source, and without source properties attached
>
>
> Yep, or does it drops off the lambda and formals from the list, thus
> losing the source position info (that being on the start of the list
> only)?
>
>         (read-enable 'positions)
>         (define (x) (display 'hello))
>         (source-properties (procedure-source x))
>         => ()
>
> Another use for positions on procedures I mentioned another time was
> to show that info in a backtrace.  When you just see "<procedure #f>"
> it's a bit of a guessing game to tell where the offending bit actually
> came from.

Except that normally the backtrace info already has it right.  For 
example, with this typed into the REPL -

guile> (define (x) (ddd))
guile> (x)

- my soon-to-be-released debugger shows the stack at the error as:

=> st (ddd)
   s  [x]
      [primitive-eval (x)]

The `s' here shows that there are source properties for the frame on 
that line, calculated as:

(if (frame-procedure? frame)
    (or (frame-source frame)
        (let ((proc (frame-procedure frame)))
          (and proc
               (procedure? proc)
               (procedure-source proc))))
    (frame-source frame))

So it looks like frame-source is getting at the info somehow - we just 
need to investigate how.

(I'll do that tomorrow evening if no one else beats me to it.)

        Neil