mirror of
https://github.com/joaotavora/yasnippet.git
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535 lines
20 KiB
EmacsLisp
535 lines
20 KiB
EmacsLisp
;;; snippet.el --- yasnippet's engine distilled -*- lexical-binding: t; -*-
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;; Copyright (C) 2013 João Távora
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;; Author: João Távora <joaotavora@gmail.com>
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;; Keywords: convenience
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;; This program is free software; you can redistribute it and/or modify
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;; it under the terms of the GNU General Public License as published by
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;; the Free Software Foundation, either version 3 of the License, or
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;; (at your option) any later version.
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;; This program is distributed in the hope that it will be useful,
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;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;; GNU General Public License for more details.
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;; You should have received a copy of the GNU General Public License
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;; along with this program. If not, see <http://www.gnu.org/licenses/>.
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;;; Commentary:
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;;
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;;; Code:
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(require 'cl-lib)
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;;; the define-snippet macro and its helpers
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;;;
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(defun snippet--form-make-field-sym (field-name &optional parent-field-sym)
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(make-symbol (format "field-%s%s" field-name
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(if parent-field-sym
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(format "-son-of-%s" parent-field-sym)
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""))))
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(defun snippet--form-make-mirror-sym (mirror-name source-field-name
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&optional parent-field-sym)
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(make-symbol (format "mirror-%s-of-%s%s" mirror-name source-field-name
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(if parent-field-sym
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(format "-son-of-%s" parent-field-sym)
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""))))
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(defvar snippet--marker-sym-obarray (make-vector 100 nil))
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(defun snippet--start-marker-name (sym)
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(intern (format "%s-beg" sym) snippet--marker-sym-obarray))
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(defun snippet--end-marker-name (sym)
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(intern (format "%s-end" sym) snippet--marker-sym-obarray))
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(defvar snippet--form-mirror-sym-idx nil)
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(defun snippet--function-p (form)
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(or (functionp form)
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(and (eq 'function (car form))
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(fboundp (cl-second form)))
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(and (eq 'quote (car form))
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(fboundp (cl-second form)))))
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(defun snippet--form-sym-tuples (forms &optional parent-field-sym)
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"Produce information for composing the snippet expansion function.
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A tuple of 6 elements is created for each form in FORMS.
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\(SYM FORM PARENT-FIELD-SYM ADJACENT-PREV-SYM PREV-FORM NEXT-FORM)
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Forms representing fields with nested elements are recursively
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iterated depth-first, resulting in a flattened list."
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(cl-loop unless forms return nil
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with snippet--form-mirror-sym-idx = (or snippet--form-mirror-sym-idx
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0)
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with adjacent-prev-sym
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for (prev-form form next-form) on `(nil ,@forms)
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for (sym childrenp) = (pcase form
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(`(field ,name . ,rest)
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(list (snippet--form-make-field-sym
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name
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parent-field-sym)
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(listp (car rest))))
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(`(mirror ,name . ,_)
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(incf snippet--form-mirror-sym-idx)
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(list (snippet--form-make-mirror-sym
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snippet--form-mirror-sym-idx
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name
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parent-field-sym))))
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append (cond (sym
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`((,sym
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,form
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,parent-field-sym
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,adjacent-prev-sym
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,prev-form
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,next-form)
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,@(when childrenp
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(snippet--form-sym-tuples (third form) sym))))
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((null form) nil)
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((or (stringp form)
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(snippet--function-p form))
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`((string-or-function ,form ,parent-field-sym)))
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(t
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(error "unknown type of snippet form %s" form)))
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do (setq adjacent-prev-sym sym)))
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(defun snippet--make-marker-init-forms (tuples)
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"Make marker init forms for the snippet objects in TUPLES.
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Imagine this snippet:
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ff1 sss mm1 ff2 mm5
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ff3 sss mm4
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I would need these somewhere in the let* form
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((ff1-beg (make-marker))
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(ff1-end (make-marker))
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(mm1-beg (make-marker))
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(mm1-end (make-marker))
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(ff2-beg mm1-end)
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(ff2-end (make-marker))
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(ff3-beg ff2-end)
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(ff3-end (make-marker))
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(mm4-beg (make-marker))
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(mm4-end ff2-end)
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(mm5-beg ff2-end)
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(mm5-end (make-marker)))
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"
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(cl-loop for (sym nil parent-sym adjacent-prev-sym prev next) in tuples
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unless (eq sym 'string-or-function)
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append `((,(snippet--start-marker-name sym)
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,(or (and adjacent-prev-sym
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(snippet--end-marker-name adjacent-prev-sym))
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(and parent-sym
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(not prev)
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(snippet--start-marker-name parent-sym))
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`(snippet--make-marker)))
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(,(snippet--end-marker-name sym)
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,(or (and parent-sym
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(not next)
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(snippet--end-marker-name parent-sym))
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`(snippet--make-marker))))))
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(defun snippet--first-field-sym (tuples)
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(car (car (snippet--field-tuples tuples))))
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(defun snippet--field-tuples (tuples)
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(cl-remove-if-not #'(lambda (form)
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(and (consp form)
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(eq 'field (car form))))
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tuples :key #'cadr))
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(defun snippet--init-field-and-mirror-forms (tuples)
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(let* ((field-mirrors (make-hash-table))
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;; we first collect `snippet--make-mirror' forms. When
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;; collecting them, we populate the `field-mirrors' table...
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;;
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(tuples (cl-remove 'string-or-function tuples :key #'car))
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(make-mirror-forms
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(cl-loop for (sym (type name transform) parent-sym) in tuples
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when (eq 'mirror type)
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collect (let ((source-sym nil))
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(cl-loop for (sym-b (type-b name-b)) in tuples
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when (and
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(eq 'field type-b)
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(eq name name-b))
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do
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(setq source-sym sym-b)
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(puthash source-sym
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(cons sym (gethash source-sym
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field-mirrors))
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field-mirrors))
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(unless source-sym
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(error "mirror mentions unknown field %s"
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name))
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`((,sym (snippet--make-mirror))
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(snippet--init-mirror
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,sym
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,source-sym
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,(snippet--start-marker-name sym)
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,(snippet--end-marker-name sym)
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,(snippet--transform-lambda transform)
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,parent-sym)))))
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;; so that we can now create `snippet--make-field' forms with
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;; complete lists of mirror symbols.
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;;
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(make-field-forms
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(cl-loop with field-tuples = (snippet--field-tuples tuples)
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for ((prev-sym)
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(sym (_type name _value) parent-sym)
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(next-sym)) on `(nil ,@field-tuples)
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when sym
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collect `((,sym (snippet--make-field))
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(snippet--init-field
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,sym
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,name
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,(snippet--start-marker-name sym)
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,(snippet--end-marker-name sym)
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,parent-sym
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(list
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,@(reverse
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(gethash sym field-mirrors)))
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,next-sym
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,prev-sym)))))
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(append make-field-forms
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make-mirror-forms)))
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(defun snippet--transform-lambda (transform-form)
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`(lambda (field-text)
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,(or transform-form
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'field-text)))
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(defun define--snippet-body (body)
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"Does the actual work for `define-snippet'"
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(let* ((sym-tuples (snippet--form-sym-tuples body))
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(marker-init-forms (snippet--make-marker-init-forms sym-tuples))
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(init-object-forms (snippet--init-field-and-mirror-forms sym-tuples))
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(first-field-sym (snippet--first-field-sym sym-tuples)))
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`(let* (,@(mapcar #'car init-object-forms)
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,@marker-init-forms)
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,@(mapcar #'second init-object-forms)
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,@(cl-loop
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for (sym form) in sym-tuples
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collect (pcase form
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(`(field ,_ ,text)
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`(snippet--insert-field ,sym ,(if (stringp text)
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text)))
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(`(mirror . ,_)
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`(snippet--insert-mirror ,sym))
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((pred stringp)
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`(insert ,form))
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((pred functionp)
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`(insert (funcall ,form)))))
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(setq snippet--field-overlay
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(make-overlay (point) (point) nil nil t))
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(overlay-put snippet--field-overlay
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'face
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'snippet-field-face)
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(overlay-put snippet--field-overlay
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'modification-hooks
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'(snippet--field-overlay-changed))
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(overlay-put snippet--field-overlay
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'insert-in-front-hooks
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'(snippet--field-overlay-changed))
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(overlay-put snippet--field-overlay
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'insert-behind-hooks
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'(snippet--field-overlay-changed))
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(overlay-put snippet--field-overlay
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'keymap
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snippet-field-keymap)
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(overlay-put snippet--field-overlay
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'snippet--objects
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(list ,@(remove 'string-or-function
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(mapcar #'car
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sym-tuples))))
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,(if first-field-sym
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`(snippet--move-to-field ,first-field-sym))
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(add-hook 'post-command-hook 'snippet--post-command-hook t t))))
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(cl-defmacro define-snippet (name () &rest body)
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"Define NAME as a snippet-inserting function.
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NAME's function definition is set to a function with no arguments
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that inserts the fields components at point.
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Each form in BODY can be:
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* A cons (field FIELD-NAME FIELD-VALUE FIELD-TRANSFORM)
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definining a snippet field. A snippet field can be navigated to
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using `snippet-next-field' and
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`snippet-prev-field'. FIELD-TRANSFORM is currently
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unimplemented.
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* A cons (mirror FIELD-NAME MIRROR-TRANSFORM) defining a mirror
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of the field named FIELD-NAME. Each time the text under the
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field changes, the form MIRROR-TRANSFORM is invoked with the
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variable `field-text' set to the text under the field. The
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string produced become the text under the mirror.
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* A string literal which is inserted as a literal part of the
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snippet and remains unchanged while the snippet is navigated.
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* A symbol designating a function which is called when the
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snippet is inserted. The string produced is treated as a
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literal string.
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* A lambda form taking no arguments, called when the snippet is
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inserted. Again, the string produced is treated as a literal
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snippet string.
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ARGS is an even-numbered property list of (KEY VAL) pairs. KEY
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can be:
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* the symbol `:obarray', in which case the symbol NAME in
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interned in the obarray VAL instead of the global obarray. This
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options is currently unimplemented."
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(declare (debug (&define name sexp &rest &or
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;; curiously, function-form doesn't work here
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;;
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("mirror" sexp def-form)
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("lambda" sexp def-form)
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("field" sexp &rest sexp)
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sexp)))
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`(defun ,name ()
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,(define--snippet-body body)))
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(cl-defmacro make-snippet (&rest body)
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"Same as `define-snippet', but return an anonymous function."
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`(lambda () ,(define--snippet-body body)))
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;;; Snippet mechanics
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;;;
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(cl-defstruct snippet--object
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start end parent-field next prev (buffer (current-buffer)))
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(cl-defstruct (snippet--field (:constructor snippet--make-field ())
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(:include snippet--object)
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(:print-function snippet--describe-field))
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name
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(mirrors '())
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next-field
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prev-field)
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(defun snippet--describe-field (field)
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(with-current-buffer (snippet--object-buffer field)
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(format "field %s from %s to %s covering \"%s\""
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(snippet--field-name field)
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(marker-position (snippet--object-start field))
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(marker-position (snippet--object-end field))
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(buffer-substring-no-properties
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(snippet--object-start field)
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(snippet--object-end field)))))
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(defun snippet--init-field (object name start end parent-field mirrors
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next-field prev-field)
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(setf (snippet--field-name object) name
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(snippet--object-start object) start
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(snippet--object-end object) end
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(snippet--object-parent-field object) parent-field
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(snippet--field-mirrors object) mirrors
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(snippet--field-next-field object) next-field
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(snippet--field-prev-field object) prev-field))
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(cl-defstruct (snippet--mirror (:constructor snippet--make-mirror ())
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(:include snippet--object)
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(:print-function snippet--describe-mirror))
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source
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(transform nil))
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(defun snippet--init-mirror (object source start end transform parent-field)
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(setf (snippet--mirror-source object) source
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(snippet--object-start object) start
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(snippet--object-end object) end
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(snippet--mirror-transform object) transform
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(snippet--object-parent-field object) parent-field))
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(defun snippet--describe-mirror (mirror)
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(with-current-buffer (snippet--object-buffer mirror)
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(format "mirror from %s to %s covering \"%s\""
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(marker-position (snippet--object-start mirror))
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(marker-position (snippet--object-end mirror))
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(buffer-substring-no-properties
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(snippet--object-start mirror)
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(snippet--object-end mirror)))))
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(defgroup snippet nil
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"Customize snippet features"
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:group 'convenience)
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(defface snippet-field-face
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'((t (:inherit 'region)))
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"Face used to highlight the currently active field of a snippet")
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(defvar snippet-field-keymap
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(let ((map (make-sparse-keymap)))
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(define-key map (kbd "<tab>") 'snippet-next-field)
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(define-key map (kbd "S-<tab>") 'snippet-prev-field)
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map)
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"The active keymap while a snippet expansion is in progress.")
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(defvar snippet--field-overlay nil)
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(defun snippet-next-field (&optional prev)
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(interactive)
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(let ((field (overlay-get snippet--field-overlay 'snippet--field)))
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(cond (prev
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(if (snippet--field-prev-field field)
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(snippet--move-to-field (snippet--field-prev-field field))
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(goto-char (snippet--object-start field))
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(snippet-exit-snippet)))
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(t
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(if (snippet--field-next-field field)
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(snippet--move-to-field (snippet--field-next-field field))
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(goto-char (snippet--object-end field))
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(snippet-exit-snippet))))))
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(defun snippet-prev-field ()
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(interactive)
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(snippet-next-field t))
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(defun snippet-exit-snippet (&optional reason)
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(delete-overlay snippet--field-overlay)
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(message "snippet exited%s"
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(or (and reason
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(format " (%s)" reason))
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"")))
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(defun snippet--make-marker ()
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(let ((marker (make-marker)))
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(set-marker-insertion-type marker t)
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(set-marker marker (point))))
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(defun snippet--open-markers (start end)
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(set-marker-insertion-type start nil)
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(set-marker-insertion-type end t))
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(defun snippet--close-markers (start end)
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(cond ((= start end)
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(set-marker-insertion-type start t)
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(set-marker-insertion-type end t))
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(t
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(set-marker-insertion-type start t)
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(set-marker-insertion-type end nil))))
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(defun snippet--call-with-current-object (object fn)
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(let* ((start (snippet--object-start object))
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(end (snippet--object-end object)))
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(unwind-protect
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(progn
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(snippet--open-markers start end)
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(funcall fn))
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(snippet--close-markers start end))))
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(defmacro snippet--with-current-object (object &rest body)
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(declare (indent defun) (debug t))
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`(snippet--call-with-current-object ,object #'(lambda () ,@body)))
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(defun snippet--insert-field (field text)
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(when text
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(snippet--with-current-object field
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(insert text))))
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(defun snippet--insert-mirror (mirror)
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(snippet--update-mirror mirror))
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(defun snippet--update-mirror (mirror)
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(snippet--with-current-object mirror
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(delete-region (snippet--object-start mirror)
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(snippet--object-end mirror))
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(save-excursion
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(goto-char (snippet--object-start mirror))
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(insert (funcall (snippet--mirror-transform mirror)
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(snippet--field-text (snippet--mirror-source mirror)))))))
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(defun snippet--move-to-field (field)
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(goto-char (snippet--object-start field))
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(move-overlay snippet--field-overlay
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(point)
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(snippet--object-end field))
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(overlay-put snippet--field-overlay 'snippet--field field))
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(defun snippet--field-overlay-changed (overlay after? _beg _end &optional _length)
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(let* ((field (overlay-get overlay 'snippet--field))
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(inhibit-modification-hooks t))
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(cond (after?
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(snippet--close-markers (snippet--object-start field)
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(snippet--object-end field))
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(mapc #'snippet--update-mirror (snippet--field-mirrors field))
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(move-overlay overlay
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(snippet--object-start field)
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(snippet--object-end field)))
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(t
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(snippet--open-markers (snippet--object-start field)
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(snippet--object-end field))))))
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(defun snippet--field-text (field)
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(buffer-substring-no-properties (snippet--object-start field)
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(snippet--object-end field)))
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(defvar snippet--debug nil)
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;; (setq snippet--debug t)
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(defun snippet--post-command-hook ()
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(cond ((and snippet--field-overlay
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(overlay-buffer snippet--field-overlay))
|
||
(cond ((or (< (point)
|
||
(overlay-start snippet--field-overlay))
|
||
(> (point)
|
||
(overlay-end snippet--field-overlay)))
|
||
(snippet-exit-snippet "point left snippet")
|
||
(remove-hook 'post-command-hook 'snippet--post-command-hook t))
|
||
(snippet--debug
|
||
(snippet--debug-snippet snippet--field-overlay))))
|
||
(snippet--field-overlay
|
||
;; snippet must have been exited for some other reason
|
||
;;
|
||
(remove-hook 'post-command-hook 'snippet--post-command-hook t))))
|
||
|
||
(defun snippet--debug-snippet (field-overlay)
|
||
(with-current-buffer (get-buffer-create "*snippet-debug*")
|
||
(let ((inhibit-read-only t))
|
||
(erase-buffer)
|
||
(let ((active-field (overlay-get field-overlay 'snippet--field)))
|
||
(cl-loop for object in (overlay-get field-overlay 'snippet--objects)
|
||
when (snippet--field-p object)
|
||
do
|
||
(insert (snippet--describe-field object))
|
||
(when (eq object active-field) (insert " (active)"))
|
||
(insert "\n")
|
||
(cl-loop for mirror in (snippet--field-mirrors object)
|
||
do (insert " " (snippet--describe-mirror mirror)
|
||
"\n")))))
|
||
(display-buffer (current-buffer))))
|
||
|
||
(provide 'snippet)
|
||
|
||
;; Local Variables:
|
||
;; coding: utf-8
|
||
;; whitespace-style: (face lines-tail)
|
||
;; whitespace-line-column: 80
|
||
;; fill-column: 80
|
||
;; End:
|
||
;; snippet.el ends here
|