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;;; Commentary:
;; This file should define all global configurable variables which
;; doesn't belong anywhere else. The config module should then import
;; this module, and set all configs as needed. The config module
;; should also be able to set configs gotten from other parts.
;;; Code:
(define-module (util config)
:use-module (srfi srfi-9)
:use-module (srfi srfi-26)
:use-module (ice-9 match)
:use-module (ice-9 format)
:use-module (util)
)
(define-once config-values (make-hash-table))
(define-record-type <config>
(make-config value documentation valid-value? source-module)
config?
(value get-value set-value!)
(documentation get-documentation)
(valid-value? get-valid-value)
(source-module get-source-module))
;; similar to emacs defcustom
;; TODO possibly make @var{documentation} and @var{valid-value?} optional.
(define-macro (define-config name default-value documentation valid-value?)
`(let ((make-config (@@ (util config) make-config))
(config-values (@@ (util config) config-values))
;; (config? (@@ (util config) config?))
(get-value (@@ (util config) get-value)))
(cond [(hashq-ref config-values (quote ,name))
=> (lambda (value)
;; When reloading a module an already defined configuration item
;; might be loaded again, just anwrap it and pretend that didn't
;; happen.
(when (,config? value)
(set! value (,get-value value)))
(unless (,valid-value? value)
(scm-error 'config-error 'define-config
"Config [~a]: ~a doesn't sattisfy predicate ~s~%\"~a\"~%"
(list (quote ,name)
value
,valid-value?
,documentation)
(list value)))
(hashq-set! config-values (quote ,name)
(make-config value ,documentation
,valid-value? (current-module))))]
;; value not set in advance
[else
(hashq-set! config-values (quote ,name)
(make-config ,default-value ,documentation
,valid-value? (current-module)))])))
(export define-config)
(define-public (set-config! key value)
(cond [(hashq-ref config-values key)
=> (cut set-value! <> value)]
[else (hashq-set! config-values key value)]))
(define %uniq (gensym))
(define*-public (get-config key optional: (default %uniq))
(let ((v (if (eq? default %uniq)
(let ((v (hashq-ref config-values key %uniq)))
(when (eq? v %uniq)
(error "Missing config" key))
v)
(hashq-ref config-values key default))))
(if (config? v)
(get-value v)
v)))
(define-public (print-configuration-documentation)
(define groups
(group-by (match-lambda [(__ v)
(if (config? v)
(get-source-module v)
#f)])
(hash-map->list list config-values )) )
(for (module values) in groups
(format #t "~%~a~%" (module-name module))
(for (key value) in values
(format #t " ~20,a | ~a~%" key (get-documentation value)))))
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