flesh/snippets/genbind.f

#!/bin/flesh

;; Flesh: Flexible Shell
;; Copyright (C) 2021 Ava Affine
;;
;; This program is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.
;;
;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.
;;
;; You should have received a copy of the GNU General Public License
;; along with this program.  If not, see <http://www.gnu.org/licenses/>.

;; GENBIND

(def gen-binding
"Takes two arguments: a symbol (use quote) and a string token
  The symbol should coorespond to a binary on the path (else command will fail)
  The string token is taken to be an argument to that command
  A lambda is then made which accepts a list of additional arguments.
  When called, the resulting function will construct and execute a call to load

The point is to be able to autogenerate bindings for shell commands.
Example: (eval ((gen-binding (q ls) '-l') ('-a')))
     Or: (def gcommit 'use: (gcommit my-message)'
           (lambda (arg) (eval ((gen-binding 'git' 'commit') ('-s' '-m' arg)))))


Or, a more advanced use:
  (def -git-opts 'all subcommands for guix'
    ('add' 'push' 'stash'))

  ;; define global functions for each subcommand
  (let ((gx-iter (pop -git-opts)))
    (while (gt? (len gx-iter) 1)
      (let ((subc (car gx-iter))
            (rest (cdr gx-iter)))
        (def (concat 'g-' subc)
          'subcommand binding for git. takes a list of args'
          (lambda (args) (eval ((gen-binding 'git' subc) args))))
        (set (q gx-iter) (pop rest)))))"
   (sym subcommand)
   (let ((lam ((q lambda)
               (cons (q args))
               (cons let (((q func-call) (cons cons (q l) (cons q sym) subcommand))
                          ((q arg-iter) (cons pop (q args))))
                       (cons while (cons gt? (cons len (q arg-iter)) 1)
                         (cons set (cons q (q func-call)) (cons cons (q func-call) (cons car (q arg-iter))))
                         (cons set (cons q (q arg-iter)) (cons pop (cons cdr (q arg-iter)))))
                       (cons echo '+ ' (cons cdr (cons pop (q func-call))))
                       (cons eval (q func-call))))))
     (eval lam)))