161 lines
6.3 KiB
EmacsLisp
161 lines
6.3 KiB
EmacsLisp
;; -*- lexical-binding: t; -*-
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(require 'ht)
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(defun syd/jump-to-target (target)
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(goto-char (car target)))
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(defvar syd/leap-action #'syd/jump-to-target)
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(defun syd/remove-highlights ()
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(remove-overlays nil nil 'category 'evil-leap))
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(defun syd/add-label (pos label)
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"TODO returns overlay"
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;; The label shall be displayed two characters /after/ `pos'. This ensures
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;; the user is able to see the entirety of the target; that is, the first
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;; character, located at `pos', and the second, immediately following.
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(let ((overlay (make-overlay (+ pos 2) (+ pos 3)))
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(label-string (string label)))
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(put-text-property 0 1 'face (list :background "red") label-string)
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(overlay-put overlay 'category 'evil-leap)
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(overlay-put overlay 'before-string label-string)
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;; Normally, we want the labels to cover the buffer's text, rather than
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;; shifting it to the side; however, doing so unconditionally will cover
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;; newlines, collapsing multiple visual lines onto one.
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(unless (= (char-after (+ pos 2)) ?\n)
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(overlay-put overlay 'invisible t))
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overlay))
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(defun syd/label-targets-safe (targets)
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"TODO returns a hash table mapping labels to targets and overlays"
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;; Nasty! While I'd prefer to iterate over `zip evil-leap-safe-labels
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;; targets`, this isn't Haskell; each iteration through `targets', we pop
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;; `labels'.
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(let ((labels evil-leap-safe-labels)
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(labeled-targets (ht-create 'eq)))
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;; The first target is assigned the label -1, to indicate that it can be
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;; auto-jumped to. The remaining targets are labeled as you'd expect.
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(ht-set! labeled-targets -1 (cons (car targets) nil))
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(dolist (tgt (cdr targets) labeled-targets)
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(pcase-let* ((`(,pos ,_ ,_) tgt)
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(lbl (pop labels))
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(overlay (syd/add-label pos lbl)))
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(ht-set! labeled-targets lbl (cons tgt overlay))))))
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(defun syd/label-targets-unsafe (targets)
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"TODO returns a hash table mapping labels to targets and overlays"
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;; TODO: space labels don't work
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(let ((labels (append evil-leap-labels (-cycle '(?\s))))
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(labeled-targets (ht-create 'eq)))
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(dolist (tgt targets labeled-targets)
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(pcase-let* ((`(,pos ,_ ,_) tgt)
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(lbl (pop labels))
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(overlay (syd/add-label pos lbl)))
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(ht-set! labeled-targets lbl (cons tgt overlay))))))
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(defun syd/label-targets (targets)
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"TODO returns a hash table mapping labels to targets and overlays. Labels are
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represented by characters. Each target is a list of form (POS LINE COLUMN
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WINDOW . XS)."
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;; Safe labels are preferred, but are not available when there are more
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;; targets than safe labels.
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(let ((safe? (<= (length targets) (length evil-leap-safe-labels))))
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;; ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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;; FIXME: I think this should be (+ 1 (length evil-leap-safe-labels)).
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(if safe?
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(syd/label-targets-safe targets)
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(syd/label-targets-unsafe targets))))
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(defun syd/do-auto-jump (labeled-targets)
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(when-let ((tgt-and-overlay (ht-get labeled-targets -1)))
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(funcall syd/leap-action (car tgt-and-overlay))))
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(defun syd/select-from-labeled-targets (labeled-targets)
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(unwind-protect
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(progn
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(syd/do-auto-jump syd/leap-action labeled-targets)
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(if-let ((given-key (evil-read-key))
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(selected-target-and-overlay (ht-get labeled-targets given-key)))
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(funcall syd/leap-action (car selected-target-and-overlay))
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(error "TODO no such label"))))
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(syd/remove-highlights))
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;;; gathering
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(defun syd/insert-branch-target (table second-char target)
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(ht-set! table
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second-char
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(cons target (ht-get table second-char))))
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(defun syd/target-at-point (&optional window)
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(list (point) (line-number-at-pos) (current-column) window))
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(defun syd/gather-branches-forward (first-char)
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"Traverse each visible two-character sequence of FIRST-CHAR followed by
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another character. The returned value will be a hash map, mapping discovered
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second characters to a list of targets representing their occurences."
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(let ((end-of-visible (window-end))
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(pattern (rx-to-string `(seq ,first-char (group anychar))))
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(table (ht-create 'equal)))
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(save-excursion
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(while (re-search-forward pattern end-of-visible t)
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;; We are forced to save-excursion a second time, lest we enter a
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;; feedback loop, where `re-search-forward' moves to a match, and
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;; `goto-char' jumps to a position *preceding* the match.
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(save-excursion
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(goto-char (match-beginning 0))
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(let ((second-char (aref (match-string 1) 0)) ; string->char
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(target (syd/target-at-point)))
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(syd/insert-branch-target table second-char target)))))
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;; Reverse each list of targets.
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(ht-each (lambda (k v) (ht-set! table k (reverse v)))
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table)
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table))
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;;; entry point
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(defun syd/label-branch-targets (branches)
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"Mutate BRANCHES by calling `syd/label-targets' on each value, and replacing
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it with the result."
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(ht-each (lambda (k tgts)
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(ht-set! branches k (syd/label-targets tgts)))
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branches))
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(defun syd/unlabel-other-branches (second-char branches)
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"Delete every overlay referenced by BRANCHES, *except* those under the branch
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with key SECOND-CHAR."
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(ht-each (lambda (k labeled-tgts)
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(unless (eq k second-char)
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(ht-each (lambda (_label tgt-and-overlay)
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;; cdr may be nil in precense of auto-jump.
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(when-let ((overlay (cdr tgt-and-overlay)))
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(delete-overlay overlay)))
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labeled-tgts)))
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branches))
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(defun syd/leap ()
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)
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(evil-define-motion syd/leap-forward (count)
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"TODO"
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:jump t
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:type 'exclusive
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(interactive)
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(let* ((first-char (evil-read-key))
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(branches (syd/gather-branches-forward first-char))
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(_ (syd/label-branch-targets branches))
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(second-char (evil-read-key))
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(_ (syd/unlabel-other-branches second-char branches))
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(labeled-targets (ht-get branches second-char)))
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;; TODO: would it be faster to go through `labeled-targets' and unlabel them
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;; ourselves?
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(unwind-protect
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(syd/select-from-labeled-targets labeled-targets)
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(syd/remove-labels))
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(syd/remove-labels)))
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