feat(wpcarro/emacs): Package maybe.el

(Temporarily) remove dependency on list.el in favor of dash, which I'm not
thrilled about.

Change-Id: Ic4348ee72582dee63ba07a183f3bda65baa7e2d6
Reviewed-on: https://cl.tvl.fyi/c/depot/+/5999
Reviewed-by: wpcarro <wpcarro@gmail.com>
Autosubmit: wpcarro <wpcarro@gmail.com>
Tested-by: BuildkiteCI

users/wpcarro/emacs/.emacs.d/wpc/buffer.el

@@ -33,6 +33,7 @@
 (require 'struct)
 (require 'ts)
 (require 'general)
+(require 'list)
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; Library

users/wpcarro/emacs/.emacs.d/wpc/math.el

@@ -13,6 +13,7 @@
 ;; Dependencies
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
+(require 'dash)
 (require 'maybe)
 (require 'cl-lib)
 
@@ -31,13 +32,13 @@
 ;; Int -> Int -> Int -> Boolean
 (cl-defun math-triangle-of-power (&key base power result)
   (cond
-   ((maybe-somes? base power result)
+   ((-all? #'maybe-some? (list base power result))
     (error "All three arguments should not be set"))
-   ((maybe-somes? power result)
+   ((-all? #'maybe-some? (list power result))
     (message "power and result"))
-   ((maybe-somes? base result)
+   ((-all? #'maybe-some? (list base result))
     (log result base))
-   ((maybe-somes? base power)
+   ((-all? #'maybe-some? (list base power))
     (expt base power))
    (t
     (error "Two of the three arguments must be set"))))

users/wpcarro/emacs/.emacs.d/wpc/maybe.el

@@ -1,78 +0,0 @@
-;;; maybe.el --- Library for dealing with nil values -*- lexical-binding: t -*-
-
-;; Author: William Carroll <wpcarro@gmail.com>
-;; Version: 0.0.1
-;; Package-Requires: ((emacs "24"))
-
-;;; Commentary:
-;; Inspired by Elm's Maybe library.
-;;
-;; For now, a Nothing value will be defined exclusively as a nil value.  I'm
-;; uninterested in supported falsiness in this module even at risk of going
-;; against the LISP grain.
-;;
-;; I'm avoiding introducing a struct to handle the creation of Just and Nothing
-;; variants of Maybe.  Perhaps this is a mistake in which case this file would
-;; be more aptly named nil.el.  I may change that.  Because of this limitation,
-;; functions in Elm's Maybe library like andThen, which is the monadic bind for
-;; the Maybe type, doesn't have a home here since we cannot compose multiple
-;; Nothing or Just values without a struct or some other construct.
-;;
-;; Possible names for the variants of a Maybe.
-;; None    | Some
-;; Nothing | Something
-;; None    | Just
-;; Nil     | Set
-;;
-;; NOTE: In Elisp, values like '() (i.e. the empty list) are aliases for nil.
-;; What else in Elisp is an alias in this way?
-;; Examples:
-;; TODO: Provide examples of other nil types in Elisp.
-
-;;; Code:
-
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-;; Dependencies
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-
-(require 'list)
-
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-;; Constants
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-
-(defvar maybe--run-tests? t
-  "When t, run the test suite defined herein.")
-
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-;; Library
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-
-(defun maybe-nil? (x)
-  "Return t if X is nil."
-  (eq nil x))
-
-(defun maybe-some? (x)
-  "Return t when X is non-nil."
-  (not (maybe-nil? x)))
-
-(defun maybe-nils? (&rest xs)
-  "Return t if all XS are nil."
-  (list-all? #'maybe-nil? xs))
-
-(defun maybe-somes? (&rest xs)
-  "Return t if all XS are non-nil."
-  (list-all? #'maybe-some? xs))
-
-(defun maybe-default (default x)
-  "Return DEFAULT when X is nil."
-  (if (maybe-nil? x) default x))
-
-(defun maybe-map (f x)
-  "Apply F to X if X is not nil."
-  (if (maybe-some? x)
-      (funcall f x)
-    x))
-
-(provide 'maybe)
-;;; maybe.el ends here