Aryadev Chavali
f8a834c0d2
Instead of exporting cantedraw.lib.macro._ and making anyone who wants to use the --> macro _require_ importing that specific symbol, let's just make it so the user has to supply a placeholder name before they do anything. This means each package provides its own placeholder symbol which lowers coupling.
92 lines
2.7 KiB
Common Lisp
92 lines
2.7 KiB
Common Lisp
;;; lib.macros.lisp - 2025-02-09
|
|
|
|
;; Copyright (C) 2025 Aryadev Chavali
|
|
|
|
;; 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 Version 2 for
|
|
;; details.
|
|
|
|
;; You may distribute and modify this code under the terms of the GNU General
|
|
;; Public License Version 2, which you should have received a copy of along with
|
|
;; this program. If not, please go to <https://www.gnu.org/licenses/>.
|
|
|
|
;;; Commentary:
|
|
|
|
;; Helpful macros for usage throughout the project.
|
|
|
|
;;; Code:
|
|
|
|
(in-package :cantedraw.lib.macros)
|
|
|
|
(defmacro --> (placeholder &body forms)
|
|
"Lexically bind current form as `placeholder' for use in the next form, returning
|
|
the result of the last form.
|
|
|
|
i.e.
|
|
|
|
(--> (a1 a2...) (b1 b2...) (c1 c2...)) =
|
|
(let* ((placeholder (a1 a2 ...))
|
|
(placeholder (b1 b2 ...))
|
|
(placeholder (c1 c2 ...)))
|
|
_ )
|
|
|
|
Also includes transformer where symbols are considered unary functions i.e.
|
|
(--> x y) <-> (--> x (y placeholder)).
|
|
"
|
|
(if (null forms)
|
|
nil
|
|
(let ((assignment-forms
|
|
(loop :for f :in forms
|
|
:for canon-f := (if (symbolp f)
|
|
(list f placeholder)
|
|
f)
|
|
:collect `(,placeholder ,canon-f))))
|
|
`(let* ,assignment-forms
|
|
,placeholder))))
|
|
|
|
(defmacro ->> (&rest forms)
|
|
"Make current form the last argument of the next form, returning the last
|
|
form.
|
|
|
|
i.e.
|
|
(->> (a1 a2...) (b1 b2...) (c1 c2...)) == (c1 c2 ... (b1 b2 ... (a1 a2 ...)))
|
|
|
|
Also includes transformer where symbols are considered unary functions.
|
|
|
|
Like the `|>' operator in Ocaml."
|
|
(if (null forms)
|
|
nil
|
|
(loop :with acc = (car forms)
|
|
:for func :in (cdr forms)
|
|
:for canon-func = (if (symbolp func) (list func) func)
|
|
:do (setq acc (append canon-func (list acc)))
|
|
:finally (return acc))))
|
|
|
|
(defmacro while (condition &body body)
|
|
`(loop :while ,condition
|
|
:do
|
|
(progn ,@body)))
|
|
|
|
(deftype -> (args result)
|
|
"Type alias for function."
|
|
`(function ,args ,result))
|
|
|
|
(defmacro fn (name lambda-list type &body body)
|
|
"Construct a function `NAME' with a declared function type `TYPE' that takes
|
|
arguments `LAMBDA-LIST' with body `BODY'."
|
|
`(progn
|
|
(declaim (ftype ,type ,name))
|
|
(defun ,name ,lambda-list
|
|
,@body)))
|
|
|
|
(defmacro $ (&rest forms)
|
|
"Given a sequence of FORMS, return a unary function which applies each form
|
|
sequentially"
|
|
`(lambda (x)
|
|
(->> x ,@(reverse forms))))
|
|
|
|
(defmacro alist-val (key alist)
|
|
"Helper macro for getting the value of KEY in ALIST."
|
|
`(cdr (assoc ,key ,alist)))
|