Re: [racket-users] Distributing application with run-time configuration

['Paulo Matos' via Racket Users]

On 12/09/2018 16:37, Matthew Flatt wrote:
> As you
> say, you could have a macro expand to the result of `(getenv "ARCH")`
> to pin it down at compile time, but you'll need to import that macro
> into two phases, since the right-hand side of
> `define-runtime-module-path-index` is implicitly used at two phases. 

Thanks for your thorough explanation of the issues. That clarified it
completely.

I have got it to working and realised that actually a compile time
configuration is more future-proof in case I end up developing a private
backend for a customer which I should ship to another customer by
mistake, therefore embedding a single backend per release is better.

I setup a file which does this to choose the backend at compile-time:
#lang racket/base
;;
---------------------------------------------------------------------------------------------------

(require (for-syntax racket/base))

(provide get-configured-backend-path)

;;
---------------------------------------------------------------------------------------------------
;; This module is used to move the compile time variable s10arch, read
from the environment
;; to a build-time variable using a macro.

(begin-for-syntax
  ;; An environment variable must be defined selecting the arch to use.
  (define s10arch (getenv "S10ARCH"))

  (unless s10arch
    (raise-user-error 'driver "Please define S10ARCH environment
variable")))

(define-syntax (get-configured-backend-path stx)
  (syntax-case stx ()
    [(_) (datum->syntax stx s10arch)]))


Then from another module I am doing:
(require s10/arch-choice)

(define-runtime-module-path-index backend-path
  (build-path (get-configured-backend-path) "name.rkt"))

However the problem here is that get-configured-backend-path does not
exist in level0 - only in level1.

I tried to provide it then like so:
(provide get-configured-backend-path
         (for-syntax get-configured-backend-path))

and then require it for syntax as well in the driver module, however
this generates the strange:
s10/arch-choice.rkt:7:21: provide: provided identifier is not defined or
required

How can get get-configured-backend-path to exist at both level which
seems to be what define-runtime-module-path-index requires?


-- 
Paulo Matos

-- 
You received this message because you are subscribed to the Google Groups 
"Racket Users" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to racket-users+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.