;;; gsexp.el --- GraphQl as S-expressions -*- lexical-binding: t -*-
;; Copyright (C) 2016-2021 Jonas Bernoulli
;; Author: Jonas Bernoulli <jonas@bernoul.li>
;; Homepage: https://github.com/magit/ghub
;; Keywords: tools
;; SPDX-License-Identifier: GPL-3.0-or-later
;; This file is not part of GNU Emacs.
;; This file 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, or (at your option)
;; any later version.
;; This file 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.
;; For a copy of the GPL see https://www.gnu.org/licenses/gpl.txt.
;;; Commentary:
;; This library encodes S-expressions as GraphQl documents. Currently
;; it is rather incomplete and only intended for use by `ghub-graphql'
;; but I might fill the gaps and add documentation eventually. I am
;; not in a hurry though.
;;; Code:
(require 'cl-lib)
(defun gsexp-encode (document)
(gsexp--pp (gsexp--encode-field document)))
(defun gsexp--encode-field (field)
(cond
((stringp field)
field)
((symbolp field)
(symbol-name field))
((listp (car field))
(concat (format "%s: " (caar field))
(gsexp--encode-field (cons (cadar field)
(cdr field)))))
(t
(concat (symbol-name (pop field))
(and (vectorp (car field))
(format " (\n%s)"
(mapconcat #'gsexp--encode-argument
(append (pop field) nil)
",\n")))
(and field
(format " {\n%s\n}"
(mapconcat #'gsexp--encode-field field "\n")))))))
(cl-defun gsexp--encode-argument ((argument value))
(format "%s: %s" argument (gsexp--encode-value value)))
(defun gsexp--encode-value (value)
(cond
((numberp value)
(number-to-string value))
((symbolp value) ; including variables, enums, booleans and null
(symbol-name value))
((stringp value)
(prin1-to-string value))
((vectorp value)
(format "(%s)" (mapconcat #'gsexp--encode-value value "")))
((listp value)
(format "{%s}" (mapconcat
(pcase-lambda (`(,name ,value))
(format "%s: %s" name (gsexp--encode-value value)))
value ", ")))
(t (error "Invalid field value: %S" value))))
(defun gsexp--pp (string)
(with-temp-buffer
(save-excursion
(insert string))
(while (< (point) (point-max))
(unless (and (bolp) (eolp))
(save-excursion
(let ((level (car (syntax-ppss (point-at-bol)))))
(when (looking-at "\\s-*\\s)")
(cl-decf level))
(indent-line-to (* 2 level)))))
(forward-line 1))
(buffer-string)))
;;; _
(provide 'gsexp)
;;; gsexp.el ends here