Proof of concept substitutions in user replacements

doc/surround.txt

@@ -138,9 +138,11 @@ specify attributes here and they will be stripped from the closing tag.
 End your input by pressing <CR> or >.  As an experimental feature, if <C-T>
 is used, the tags will appear on lines by themselves.
 
-An experimental replacement of a LaTeX environment is provided on \ and l.
+A deprecated replacement of a LaTeX environment is provided on \ and l.
 The name of the environment and any arguments will be input from a prompt.
-The following shows the resulting environment from csp\tabular}{lc<CR>
+This will be removed once a more fully functional customization system is
+implemented.  The following shows the resulting environment from
+csp\tabular}{lc<CR>
 >
   \begin{tabular}{lc}
   \end{tabular}
@@ -164,6 +166,29 @@ replacements.
   let g:surround_45 = "<% \r %>"
   let g:surround_61 = "<%= \r %>"
 <
+Advanced, experimental, and subject to change:  One can also prompt for
+replacement text.  The syntax for this is to surround the replacement in pairs
+of low numbered controller characters.  If this sounds confusing, that's
+because it is (but it makes the parsing easy).  Consider the following example
+for a LaTeX environment on the "l" replacement.
+>
+  let g:surround_108 = "\\begin{\1environment: \1}\r\\end{\1\1}"
+<
+When this replacement is used,  the user is prompted with an "environment: "
+prompt for input.  This input is inserted between each set of \1's.
+Additional inputs up to \7 can be used.
+
+Furthermore, one can specify a regular expression substitution to apply.
+>
+  let g:surround_108 = "\\begin{\1environment: \1}\r\\end{\1\r}.*\r\1}"
+<
+This will remove anything after the first } in the input when the text is
+placed within the \end{} slot.  The first \r marks where the pattern begins,
+and the second where the replacement text begins.
+
+Inputting text replacements is a proof of concept at this point. The ugly,
+unintuitive interface and the brevity of the documentation reflect this.
+
 ISSUES                                          *surround-issues*
 
 Vim could potentially get confused when deleting/changing occurs at the very
@@ -172,7 +197,8 @@ end of the line.  Please report any repeatable instances of this.
 Do we need to use |inputsave()|/|inputrestore()| with the tag replacement?
 
 Customization isn't very flexible.  Need a system that allows for prompting,
-like with HTML tags and LaTeX environments.
+like with HTML tags and LaTeX environments.  (There is an experimental
+interface for this now).
 
 Indenting is handled haphazardly.  Need to decide the most appropriate
 behavior and implement it.  Right now one can do :let b:surround_indent = 1
@@ -180,4 +206,5 @@ behavior and implement it.  Right now one can do :let b:surround_indent = 1
 should this be the default?
 
 It would be nice if |.| would work to repeat an operation.
+
  vim:tw=78:ts=8:ft=help:norl:

plugin/surround.vim

@@ -111,6 +111,47 @@ function! s:fixindent(str,spc)
     return str
 endfunction
 
+function! s:process(string)
+    let i = 0
+    while i < 7
+        let i = i + 1
+        let repl_{i} = ''
+        let m = matchstr(a:string,nr2char(i).'.\{-\}\ze'.nr2char(i))
+        if m != ''
+            let m = substitute(strpart(m,1),'\r.*','','')
+            let repl_{i} = input(substitute(m,':\s*$','','').': ')
+        endif
+    endwhile
+    let s = ""
+    let i = 0
+    while i < strlen(a:string)
+        let char = strpart(a:string,i,1)
+        if char2nr(char) < 8
+            let next = stridx(a:string,char,i+1)
+            if next == -1
+                let s = s . char
+            else
+                let insertion = repl_{char2nr(char)}
+                let subs = strpart(a:string,i+1,next-i-1)
+                let subs = matchstr(subs,'\r.*')
+                echo substitute(subs,'\r','R','g')
+                while subs =~ '^\r.*\r'
+                    let sub = matchstr(subs,"^\r\\zs[^\r]*\r[^\r]*")
+                    let subs = strpart(subs,strlen(sub)+1)
+                    let r = stridx(sub,"\r")
+                    let insertion = substitute(insertion,strpart(sub,0,r),strpart(sub,r+1),'')
+                endwhile
+                let s = s . insertion
+                let i = next
+            endif
+        else
+            let s = s . char
+        endif
+        let i = i + 1
+    endwhile
+    return s
+endfunction
+
 function! s:wrap(string,char,type,...)
     let keeper = a:string
     let newchar = a:char
@@ -133,11 +174,13 @@ function! s:wrap(string,char,type,...)
     endif
     let idx = stridx(pairs,newchar)
     if exists("b:surround_".char2nr(newchar))
-        let before = s:extractbefore(b:surround_{char2nr(newchar)})
-        let after  =  s:extractafter(b:surround_{char2nr(newchar)})
+        let all    = s:process(b:surround_{char2nr(newchar)})
+        let before = s:extractbefore(all)
+        let after  =  s:extractafter(all)
     elseif exists("g:surround_".char2nr(newchar))
-        let before = s:extractbefore(g:surround_{char2nr(newchar)})
-        let after  =  s:extractafter(g:surround_{char2nr(newchar)})
+        let all    = s:process(g:surround_{char2nr(newchar)})
+        let before = s:extractbefore(all)
+        let after  =  s:extractafter(all)
     elseif newchar ==# "p"
         let before = "\n"
         let after  = "\n\n"
@@ -427,6 +470,7 @@ function! s:opfunc(type,...) " {{{1
     let &selection = "inclusive"
     let reg_save = getreg(reg)
     let reg_type = getregtype(reg)
+    "call setreg(reg,"\n","c")
     let type = a:type
     if a:type == "char"
         silent exe 'norm! v`[o`]"'.reg."y"
@@ -437,7 +481,12 @@ function! s:opfunc(type,...) " {{{1
     elseif a:type ==# "v" || a:type ==# "V" || a:type ==# "\<C-V>"
         silent exe 'norm! gv"'.reg."y"
     elseif a:type =~ '^\d\+$'
+        let type = 'v'
         silent exe 'norm! ^v'.a:type.'$h"'.reg.'y'
+        if mode() == 'v'
+            norm! v
+            return s:beep()
+        endif
     else
         let &selection = sel_save
         return s:beep()