guix/monad-repl.scm

   1 ;;; GNU Guix --- Functional package management for GNU
   2 ;;; Copyright © 2014, 2015, 2016 Ludovic Courtès <ludo@gnu.org>
   3 ;;;
   4 ;;; This file is part of GNU Guix.
   5 ;;;
   6 ;;; GNU Guix is free software; you can redistribute it and/or modify it
   7 ;;; under the terms of the GNU General Public License as published by
   8 ;;; the Free Software Foundation; either version 3 of the License, or (at
   9 ;;; your option) any later version.
  10 ;;;
  11 ;;; GNU Guix is distributed in the hope that it will be useful, but
  12 ;;; WITHOUT ANY WARRANTY; without even the implied warranty of
  13 ;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 ;;; GNU General Public License for more details.
  15 ;;;
  16 ;;; You should have received a copy of the GNU General Public License
  17 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
  18
  19 (define-module (guix monad-repl)
  20   #:use-module (guix store)
  21   #:use-module (guix monads)
  22   #:use-module (guix utils)
  23   #:use-module (guix packages)
  24   #:use-module (ice-9 pretty-print)
  25   #:use-module (system repl repl)
  26   #:use-module (system repl common)
  27   #:use-module (system repl command)
  28   #:use-module (system base language)
  29   #:use-module (system base compile)
  30   #:use-module (srfi srfi-26)
  31   #:export (run-in-store
  32             enter-store-monad))
  33
  34 ;;; Comment:
  35 ;;;
  36 ;;; This modules provides a couple of REPL meta-commands that make it easier
  37 ;;; to work with monadic procedures in the store monad.
  38 ;;;
  39 ;;; Code:
  40
  41 (define* (monad-language monad run #:optional (name 'monad))
  42   "Return a language with a special evaluator that causes monadic values
  43  to be \"run\" in MONAD using procedure RUN."
  44   (let ((scheme (lookup-language 'scheme)))
  45     (define (evaluate-monadic-expression exp env)
  46       (let ((mvalue (compile exp #:to 'value #:env env)))
  47         (run mvalue)))
  48
  49     (make-language #:name name
  50                    #:title "Monad"
  51                    #:reader (language-reader scheme)
  52                    #:compilers (language-compilers scheme)
  53                    #:decompilers (language-decompilers scheme)
  54                    #:evaluator evaluate-monadic-expression
  55                    #:printer (language-printer scheme)
  56                    #:make-default-environment
  57                    (language-make-default-environment scheme))))
  58
  59 (define* (default-guile-derivation store #:optional (system (%current-system)))
  60   "Return the derivation of the default "
  61   (package-derivation store (default-guile) system))
  62
  63 (define (store-monad-language store)
  64   "Return a compiler language for the store monad using STORE."
  65   (let ((guile (or (%guile-for-build)
  66                    (default-guile-derivation store))))
  67     (monad-language %store-monad
  68                     (cut run-with-store store <>
  69                          #:guile-for-build guile)
  70                     'store-monad)))
  71
  72 (define-meta-command ((run-in-store guix) repl (form))
  73   "run-in-store EXP
  74 Run EXP through the store monad."
  75   (with-store store
  76     (let* ((guile (or (%guile-for-build)
  77                       (default-guile-derivation store)))
  78            (value (run-with-store store (repl-eval repl form)
  79                                   #:guile-for-build guile)))
  80       (run-hook before-print-hook value)
  81       (pretty-print value))))
  82
  83 (define-meta-command ((enter-store-monad guix) repl)
  84   "enter-store-monad
  85 Enter a REPL for values in the store monad."
  86   (with-store store
  87     (let ((new (make-repl (store-monad-language store))))
  88       ;; Force interpretation so that our specially-crafted language evaluator
  89       ;; is actually used.
  90       (repl-option-set! new 'interp #t)
  91       (run-repl new))))
  92
  93 ;;; monad-repl.scm ends here