Aryadev Chavali
de653b67fb
f $ g $ h -> f(g(h)) whereas previous implementation ($ f g h) was h(g(f)).
90 lines
2.6 KiB
Common Lisp
90 lines
2.6 KiB
Common Lisp
;;; lib.macros.lisp - 2025-02-09
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;; Copyright (C) 2025 Aryadev Chavali
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;; This program is distributed in the hope that it will be useful, but WITHOUT
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;; ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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;; FOR A PARTICULAR PURPOSE. See the GNU General Public License Version 2 for
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;; details.
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;; You may distribute and modify this code under the terms of the GNU General
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;; Public License Version 2, which you should have received a copy of along with
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;; this program. If not, please go to <https://www.gnu.org/licenses/>.
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;;; Commentary:
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;; Helpful macros for usage throughout the project.
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;;; Code:
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(in-package :lib.macros)
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(defmacro --> (&rest forms)
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"Lexically bind current form as `_' for use in the next form, returning the
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result of the last form.
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i.e.
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(--> (a1 a2...) (b1 b2...) (c1 c2...)) =
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(let* ((_ (a1 a2 ...))
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(_ (b1 b2 ...))
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(_ (c1 c2 ...)))
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_ )
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Also includes transformer where symbols are considered unary functions i.e.
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(--> x y) <-> (--> x (y _)).
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"
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(if (null forms)
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nil
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(let ((assignment-forms
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(loop :for f :in forms
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:for canon-f = (if (symbolp f) (list f 'lib.macros:_) f)
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:collect `(lib.macros:_ ,canon-f))))
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`(let* ,assignment-forms
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lib.macros:_))))
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(defmacro ->> (&rest forms)
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"Make current form the last argument of the next form, returning the last
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form.
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i.e.
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(->> (a1 a2...) (b1 b2...) (c1 c2...)) == (c1 c2 ... (b1 b2 ... (a1 a2 ...)))
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Also includes transformer where symbols are considered unary functions.
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Like the `|>' operator in Ocaml."
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(if (null forms)
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nil
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(loop :with acc = (car forms)
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:for func :in (cdr forms)
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:for canon-func = (if (symbolp func) (list func) func)
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:do (setq acc (append canon-func (list acc)))
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:finally (return acc))))
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(defmacro while (condition &body body)
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`(loop :while ,condition
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:do
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(progn ,@body)))
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(deftype -> (args result)
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"Type alias for function."
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`(function ,args ,result))
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(defmacro fn (name lambda-list type &body body)
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"Construct a function `NAME' with a declared function type `TYPE' that takes
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arguments `LAMBDA-LIST' with body `BODY'."
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`(progn
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(declaim (ftype ,type ,name))
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(defun ,name ,lambda-list
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,@body)))
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(defmacro $ (&rest forms)
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"Given a sequence of FORMS, return a unary function which applies each form
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sequentially"
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`(lambda (x)
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(->> x ,@(reverse forms))))
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(defmacro alist-val (key alist)
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"Helper macro for getting the value of KEY in ALIST."
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`(cdr (assoc ,key ,alist)))
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