From 994de513a23210f1f4d50d24270f8f988abdd21c Mon Sep 17 00:00:00 2001
From: Gerion Entrup <gerion.entrup@flump.de>
Date: Wed, 19 Jul 2017 00:13:52 +0200
Subject: [PATCH] t-vim: extended escape mode

With this change it is possible to define one or more escapechars, that
are used by vim to recognize parts that should not be interpreted.
---
 2context.vim | 50 +++++++++++++++++++++++++++++++++-----------------
 t-vim.tex    | 12 ++----------
 2 files changed, 35 insertions(+), 27 deletions(-)

diff --git a/2context.vim b/2context.vim
index 9c72ba1..b208e65 100644
--- a/2context.vim
+++ b/2context.vim
@@ -8,6 +8,11 @@
 " output buffer. The script parses content line-by-line from the first buffer
 " and pastes the modified result on the second buffer.
 
+" Compare a char of <string> at <bytepos> with some Unicode <ochar>
+function UnicodeCompare(string, bytepos, ochar)
+    return strpart(a:string, a:bytepos, max([strlen(a:ochar), 1])) ==# a:ochar
+endfunction
+
 " Split screen and go to the second buffer, ensure modifiable is set, and the
 " buffer is empty.
 sblast 
@@ -38,9 +43,9 @@ if !exists("highlight")
   let highlight=[]
 endif
 
-" Set escapecomments
-if !exists("escapecomments")
-  let escapecomments=0
+" Set escapechar
+if !exists("escapechar")
+  let escapechar=''
 endif
 
 let s:strip = strlen( matchstr( getline(s:lstart), '^\s*' ) )
@@ -71,37 +76,48 @@ let s:lines = []
 let s:buffer_lnum = 1
 let s:lnum = s:lstart
 
+let s:lenesc = strlen(escapechar)
+
 while s:lnum <= s:lstop
 " Get the current line
   let s:line = getline(s:lnum)
   let s:len  = strlen(s:line)
-  let s:new  = '' 
+  let s:new  = ''
 
 " Loop over each character in the line
-  let s:col = s:strip + 1
-  while s:col <= s:len
+  let s:col = s:strip
+  while s:col < s:len
     let s:startcol = s:col " The start column for processing text
-    let s:id       = synID (s:lnum, s:col, 1)
-    let s:col      = s:col + 1
+    let s:temp = ''
+" ignore escaped sequences
+    if UnicodeCompare(s:line, s:col, escapechar)
+      let s:nextesc = stridx(s:line, escapechar, s:col + 1)
+      let s:temp      = strpart(s:line, s:col + s:lenesc, s:nextesc - s:col - s:lenesc)
+      let s:col       = s:nextesc + s:lenesc
+      let s:startcol  = s:col
+    endif
+    if s:col > s:len
+      let s:id   = 0 " dummy id if whole line is escaped
+    else
+      let s:id       = synID (s:lnum, s:col + 1, 1)
+      let s:col      = s:col + 1
 " Speed loop (it's small - that's the trick)
-" Go along till we find a change in synID
-    while s:col <= s:len && s:id == synID(s:lnum, s:col, 1) 
-      let s:col = s:col + 1 
-    endwhile
+" Go along till we find a change in synID or an escapechar
+      while s:col < s:len && !UnicodeCompare(s:line, s:col, escapechar) && s:id == synID(s:lnum, s:col + 1, 1)
+        let s:col = s:col + 1
+      endwhile
+    endif
 
 " Output the text with the same synID, with class set to {s:id_name}
     let s:id      = synIDtrans (s:id)
     let s:id_name = synIDattr  (s:id, "name", "gui")
-    let s:temp    = strpart(s:line, s:startcol - 1, s:col - s:startcol)
+    let s:part    = strpart(s:line, s:startcol, s:col - s:startcol)
+    let s:temp    = s:temp . escape( s:part, '\{}')
 " Remove line endings (on unix machines reading windows files)
     let s:temp    = substitute(s:temp, '\r*$', '', '')
 " It might have happened that that one has been the last item in a row, so
 " we don't need to print in in that case
     if strlen(s:temp) > 0
-" Change special TeX characters to escape sequences.
-      if !(escapecomments && s:id_name == "Comment")
-        let s:temp = escape( s:temp, '\{}')
-      endif
       if !empty(s:id_name)
         let s:temp = '\SYN[' . s:id_name . ']{' . s:temp .  '}'
       endif
diff --git a/t-vim.tex b/t-vim.tex
index 542261f..9d0bb50 100644
--- a/t-vim.tex
+++ b/t-vim.tex
@@ -129,7 +129,7 @@
        -c "let contextstartline=\externalfilterparameter\c!start \letterbar\space %
            let contextstopline=\externalfilterparameter\c!stop   \letterbar\space %
            let strip=\getvalue{\vimtyping@id-\c!strip-\externalfilterparameter\c!strip}" %
-       -c "let escapecomments=\getvalue{\vimtyping@id-\c!escape-\externalfilterparameter\c!escape}" %
+       -c "let escapechar='°'" %
        -c "let highlight=[\externalfilterparameter\c!highlight]" %
        \vimrc_extras\space
        -c "source \vimtyping@script_name" %
@@ -140,18 +140,10 @@
 \setvalue{\vimtyping@id-\c!strip-\v!off}{0}
 \setvalue{\vimtyping@id-\c!strip-\v!on}{1}
 
-\setvalue{\vimtyping@id-\c!escape-\v!off}{0}
-\setvalue{\vimtyping@id-\c!escape-\v!on}{1}
-
-
 % Undocumented ... but useful if the user makes a mistake
 \setvalue{\vimtyping@id-\c!strip-\v!no}{0}
 \setvalue{\vimtyping@id-\c!strip-\v!yes}{1}
 
-\setvalue{\vimtyping@id-\c!escape-\v!no}{0}
-\setvalue{\vimtyping@id-\c!escape-\v!yes}{1}
-
-
 \setupvimtyping
   [% \c!tab=4,
    % \c!start=1,
@@ -163,7 +155,7 @@
    % \c!style=\tttf,
    % \c!color=,
    \c!strip=\v!off,
-   \c!escape=\v!off,
+   % \c!escapechar=,
    % \c!highlight=,
    % \c!highlightcolor=lightgray,
    \c!filtercommand=\vimtyping@filter_command,
-- 
2.13.0