ledger.vim: use full width, not only 80 chars

Also add option g:ledger_maxwidth to provide old behaviour
by putting a line like this in .vimrc:
let g:ledger_maxwidth = 80

I think that it would make sense to put all the functions and
everything that has to do with foldtext in ftplugin/ledger.vim

contrib/ledger.vim

@@ -1,17 +1,20 @@
 " Vim syntax file
 " filetype: ledger
-" Version: 0.0.5
+" Version: 0.1.0
 " by Johann Klähn; Use according to the terms of the GPL>=2.
 " by Stefan Karrmann; Use according to the terms of the GPL>=2.
 " by Wolfgang Oertl; Use according to the terms of the GPL>=2.
 " Revision history
-"  2009-03-25  J. Klähn: Allow Metadata in postings (Ledger 3.0)
+"  2009-06-12  J. Klähn: Use all available columns for foldtext
+"  2009-03-25  J. Klähn: Allow Metadata
+"              in transactions and postings (Ledger 3.0)
 "              Also fixed alignment for multi-byte-characters
 "  2009-01-28  S.Karrmann: minor fixes
 "  2009-01-27  third version by S.Karrmann.
 "              better extraction of the amount of the posting
 "              decimal separator can be one of '.' and ','.
 "  2005-02-05  first version (partly copied from ledger.vim 0.0.1)
+" vim:ts=2:sw=2:sts=2:foldmethod=marker
 
 if version < 600
   syntax clear
@@ -19,56 +22,103 @@ elseif exists("b:current_sytax")
   finish
 endif
 
+" You can set a maximal number of columns the fold text (excluding amount)
+" will use by overriding g:ledger_maxwidth in your .vimrc.
+" When maxwidth is zero, the amount will be displayed at the far right side
+" of the screen.
+if !exists('g:ledger_maxwidth')
+  let g:ledger_maxwidth = 0
+endif
+ 
 " for debugging
 syntax clear
  
-" region: a normal posting
+" region: a transaction containing postings
-syn region postNorm start=/^\d/ skip=/^\s/ end=/^/ fold keepend transparent contains=postDate,Metadata
+syn region transNorm start=/^\d/ skip=/^\s/ end=/^/
-syn match postDate /^\d\S\+/ contained
+    \ fold keepend transparent contains=transDate, Metadata
+syn match transDate /^\d\S\+/ contained
 syn match Metadata /^\s\+;.*/ contained
 syn match Comment /^;.*$/
 
 highlight default link Comment SpecialKey
 highlight default link Metadata SpecialKey
-highlight default link postDate Question
+highlight default link transDate Question
  
-" folding: how to represent a posting in one line.
+function! s:multibyte_strlen(text) "{{{
+   return strlen(substitute(a:text, ".", "x", "g"))
+endf "}}}
+
+function s:get_columns(win) "{{{
+  " As long as vim doesn't provide a command natively,
+  " we have to compute the available columns.
+  " see :help todo.txt -> /Add argument to winwidth()/
+  " FIXME: Although this will propably never be used with debug mode enabled
+  "        this should take the signs column into account (:help sign.txt)
+  let columns = (winwidth(a:win) == 0 ? 80 : winwidth(a:win)) - &foldcolumn
+  if &number
+    " line('w$') is the line number of the last line
+    let columns -= max([len(line('w$'))+1, &numberwidth])
+  endif
+  return columns
+endf "}}}
+
+let s:rx_amount = '\('.
+                \   '\%([0-9]\+\)'.
+                \   '\%([,.][0-9]\+\)*'.
+                \ '\|'.
+                \   '[,.][0-9]\+'.
+                \ '\)'.
+                \ '\s*\%([[:alpha:]¢$€£]\+\s*\)\?'.
+                \ '\%(\s*;.*\)\?$'
+
+" folding: how to represent a transaction in one line.
 function! LedgerFoldText()
-   let line = strpart(getline(v:foldstart), 0, 99)
+  " find amount
-   let amount = ""
+  let amount = ""
+  let lnum = v:foldstart
+  while lnum <= v:foldend
+    let line = getline(lnum)
 
-   let delta = 1
+    " Skip metadata/leading comment
-   while (delta >= 1 && delta < (v:foldend-v:foldstart+1))
+    if line !~ '^\s\+;'
-      let other_line = getline(v:foldstart+delta)
+      " No comment, look for amount...
-      
+      let groups = matchlist(line, s:rx_amount)
-      if len(matchstr(other_line, '^\s\+;')) != 0
+      echomsg string(groups)
-         " Skip metadata/leading comment
+      if ! empty(groups)
-         let delta = delta + 1
+        echomsg amount
-      else
+        let amount = groups[1]
-         " No comment, look for amount...
+        break
-         let delta = -1
-         let lst = matchlist(other_line,'\(\%([0-9]\+[,.]\)\=[0-9]\+\%([,.][0-9]\+\)\=\|[,.][0-9]\+\)\s*\%([A-Za-z$€¢]\+\s*\)\=\%(\s*;.*\)\=$')
-         if (len(lst) != 0)
-            let amount = lst[1]
-         endif
       endif
-   endwhile
+    endif
+    let lnum += 1
+  endwhile
 
-   " Replace each char with x prior to counting
+  let fmt = '%s %s '
-   " this fixes problems with multi byte characters
+  " strip whitespace at beginning and end of line
-   let pad_len = 80 - strlen(substitute(line, ".", "x", "g")) - strlen(substitute(amount, ".", "x", "g"))
+  let foldtext = substitute(getline(v:foldstart),
+                          \ '\(^\s\+\|\s\+$\)', '', 'g')
 
-   if (pad_len < 0)
+  " number of columns foldtext can use
-      pad_len = 0
+  let columns = s:get_columns(0)
-   endif
+  if g:ledger_maxwidth
-   let pad = strpart("                                                                                                                      ", 0, pad_len)
+    let columns = min([columns, g:ledger_maxwidth])
-   return line . pad . amount
+  endif
+  let columns -= s:multibyte_strlen(printf(fmt, '', amount))
+
+  " add spaces so the text is always long enough when we strip it
+  " to a certain width (fake table)
+  let foldtext .= repeat(' ', s:get_columns(0))
+  " we don't use slices[:5], because that messes up multibyte characters
+  let foldtext = substitute(foldtext, '.\{'.columns.'}\zs.*$', '', '')
+
+  return printf(fmt, foldtext, amount)
 endfunction
+
 set foldtext=LedgerFoldText()
 set foldmethod=syntax
  
-" syncinc is easy: search for the first posting.
+" syncinc is easy: search for the first transaction.
 syn sync clear
-syn sync match ledgerSync grouphere postNorm "^\d"
+syn sync match ledgerSync grouphere transNorm "^\d"
  
 let b:current_syntax = "ledger"