51 lines
2.3 KiB
EmacsLisp
Executable File
51 lines
2.3 KiB
EmacsLisp
Executable File
;;; -*- lexical-binding: t -*-
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;;;
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;;; This is one of my config's weirder bits. My config is organised into many
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;;; disjoint "modules," configuring one group of related things at a time. I
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;;; want these modules to be as independent as possible — you should be able to
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;;; add and remove individual modules and the only modules that should stop
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;;; working are those which inherently build off of the removed module's
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;;; functionality. Thus, I want to discourage any reliance on some implicit
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;;; load order — all dependencies should be explicit. As one method to shake
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;;; the tree of dependencies, so to speak, I came up with the idea of loading my
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;;; "top-level" modules in a pseudo-random order, which has proven incredibly
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;;; effective in catching accidental implicit dependencies thus far!
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(require 'cl-lib)
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(defconst syd-init-load-order-seed
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(or (when-let ((x (getenv "SYD_INIT_LOAD_ORDER_SEED")))
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(string-to-number x))
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(random))
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"Seed used to load top-level modules in pseudo-random order. Loading modules
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in an unpredictable order by default is a tactic to prevent implicit
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dependencies between modules. For debugging purposes, the load-order may be
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made deterministic by starting Emacs with the environment variable
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SYD_INIT_LOAD_ORDER_SEED set to a non-negative integer.")
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;; Log as early as possible to make it difficult to miss.
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(message "Top-level modules will be loaded in the order determined by SYD_INIT_LOAD_ORDER_SEED=%d"
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syd-init-load-order-seed)
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(defun syd-random-permutation (lst &optional seed)
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"Return a random permutation of list LST using SEED as the random state. The
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permutation is deterministic for a given SEED."
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(let* ((random-state (cl-make-random-state (or seed (random))))
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(len (length lst))
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(vec (vconcat lst)))
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;; Fisher-Yates shuffle.
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(cl-loop for i from (1- len) downto 1 do
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(cl-rotatef (aref vec i)
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(aref vec (cl-random (1+ i) random-state))))
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;; Convert vector to list.
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(append vec nil)))
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(defun syd-require-features (features)
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"Require each of FEATURES in the pseudo-random order defined by
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`syd-init-load-order-seed' and `syd-random-permutation'."
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(dolist (feature (syd-random-permutation
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features syd-init-load-order-seed))
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(require feature)))
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(provide 'syd/random-require)
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