From 57608dd23b6be224c74a03f2d27112b9b08f4816 Mon Sep 17 00:00:00 2001
From: Tom Ryder <tom@sanctum.geek.nz>
Date: Sat, 29 Dec 2018 22:03:42 +1300
Subject: First version

---
 autoload/regex_escape.vim | 69 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 69 insertions(+)
 create mode 100644 autoload/regex_escape.vim

(limited to 'autoload/regex_escape.vim')

diff --git a/autoload/regex_escape.vim b/autoload/regex_escape.vim
new file mode 100644
index 0000000..06b3c07
--- /dev/null
+++ b/autoload/regex_escape.vim
@@ -0,0 +1,69 @@
+" Define Vim pattern character classes of characters that should have an
+" escape character added before them to make them literal, for use in
+" substitute()
+let s:classes = {
+      \ 'bre': '[][\.*?^$]',
+      \ 'ere': '[][\.*?^$+{}()/]',
+      \ 'vim': '[][\.*^$~]'
+      \ }
+
+" This function does the actual translation, defined as 'operatorfunc' for the
+" mapping in both normal and visual mode
+function! regex_escape#Operatorfunc(type) abort
+
+  " Save the current value of the unnamed register and the current value of
+  " the 'clipboard' and 'selection' options into a dictionary for restoring
+  " after this is all done
+  let l:save = {
+        \ 'register': @@,
+        \ 'clipboard': &clipboard,
+        \ 'selection': &selection
+        \ }
+
+  " Don't involve any system clipboard for the duration of this function
+  set clipboard-=unnamed
+  set clipboard-=unnamedplus
+
+  " Ensure that we include end-of-line and final characters in selections
+  set selection=inclusive
+
+  " Select or re-select text, depending on how we were invoked
+  if a:type ==# 'line'
+    execute "normal! '[V']y"
+  elseif a:type ==# 'block'  " Typically doesn't work too well
+    execute "normal! `[\<C-V>`]y"  "
+  else
+    execute "normal! `[v`]y"
+  endif
+
+  " Determine the regex flavor to use; if one is defined for the buffer, use
+  " that; failing that, if one is defined globally in g:regex_escape_flavor,
+  " use that; failing that, just use 'bre'
+  let l:flavor = get(b:, 'regex_escape_flavor',
+        \ get(g:, 'regex_escape_flavor', 'bre'))
+
+  " Get the corresponding character class
+  let l:class = s:classes[l:flavor]
+
+  " Perform the substitution on the unnamed register's contents, inserting a
+  " backslash before every instance of any character in that class
+  let @@ = substitute(@@, l:class, '\\&', 'g')
+
+  " Paste our substituted changes back in over the top of the previously
+  " selected text, by reselecting it before the paste
+  normal! gvp
+
+  " Restore contents of the unnamed register and the previous values of the
+  " 'clipboard' and 'selection' options.
+  let @@ = l:save['register']
+  let &clipboard = l:save['clipboard']
+  let &selection = l:save['selection']
+
+endfunction
+
+" Expression mapping target function; set the 'operatorfunc' and return the
+" key sequence to active it
+function! regex_escape#Map() abort
+  set operatorfunc=regex_escape#Operatorfunc
+  return 'g@'
+endfunction
-- 
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