[Chicken-janitors] [Chicken-bugs] #345: foreign-lambda* misfeature

[Chicken Scheme]

#345: foreign-lambda* misfeature
------------------------+---------------------------------------------------
Reporter:  elf          |       Owner:                                          
  
    Type:  enhancement  |      Status:  new                                     
  
Priority:  minor        |   Component:  compiler                                
  
 Version:  2.7          |    Keywords:  ffi, foreign-lambda, variable 
substitution
------------------------+---------------------------------------------------
 due to the quoting in the foreign-lambda* macro, it is impossible to
 substitute platform-dependent strings.  example:[[BR]]
 {{{
 (cond-expand
     (linux
         (define insstr "sendto(blah, blah, blah)"))
     (macos
         (define insstr "sendmsg(blah, blah, 0, blah)"))
     (mingw
         (define insstr "write(blah, blah, blah)"))
     (else
         (error "not supported")))

 (define do-send
     (foreign-lambda* int ((type var))
         "some setup stuff"
          insstr
          "more stuff"))
 }}}

 i have also tried this with #<< and #<#, and with a string-append at the
 beginning, and with creating the entire string outside of the foreign-
 lambda... what finally worked is the following:

 {{{
 (define-for-syntax foo "y +=1 ")

 (define-macro (foreign-lambda-wrap ret args . body)
     `(foreign-lambda* ,ret (,@args)
         ,@(map (lambda (x)
                    (if (string? x)
                        x
                        (let ((y   (eval x))
                            (if (string? y)
                                y
                                x))))
                body)))

 (define blah (foreign-lambda-wrap
 <code that looks like foreign-lambda* but accepts variables for
 string substitution>))

 }}}

 this seems like a lot of extra work to get around quoting.  any
 thoughts/suggestions?

-- 
Ticket URL: <http://trac.callcc.org/ticket/345>
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