Extract classpath.vim to a separate plugin

Keeping it in the repository, for now.  Disable it with

	let g:no_foreplay_classpath = 1

This eliminates the startup delay at the cost of requiring a REPL to
evaluate code.

References #3.

autoload/classpath.vim

@@ -1,4 +1,4 @@
-" classpath.vim - Manipulate the Java class path
+" autoload/classpath.vim
 " Maintainer:   Tim Pope <http://tpo.pe>
 
 if exists("g:autoloaded_classpath")

plugin/classpath.vim

@@ -0,0 +1,23 @@
+" classpath.vim - Set 'path' from the Java class path
+" Maintainer:   Tim Pope <http://tpo.pe/>
+
+if exists('g:no_foreplay_classpath') || exists("g:loaded_classpath") || v:version < 700 || &cp
+  finish
+endif
+let g:loaded_classpath = 1
+
+if &viminfo !~# '!'
+  set viminfo+=!
+endif
+
+augroup classpath
+  autocmd!
+  autocmd FileType clojure
+        \ if expand('%:p') =~# '^zipfile:' |
+        \   let &l:path = getbufvar('#', '&path') |
+        \ else |
+        \   let &l:path = classpath#detect() |
+        \ endif
+augroup END
+
+" vim:set et sw=2:

plugin/foreplay.vim

@@ -11,16 +11,8 @@ let g:loaded_foreplay = 1
 augroup foreplay_file_type
   autocmd!
   autocmd BufNewFile,BufReadPost *.clj setfiletype clojure
-  autocmd FileType clojure
-        \ if expand('%:p') !~# '^zipfile:' |
-        \   let &l:path = classpath#detect() |
-        \ endif
 augroup END
 
-if &viminfo !~# '!'
-  set viminfo+=!
-endif
-
 " }}}1
 " Escaping {{{1
 
@@ -366,8 +358,11 @@ function! foreplay#local_client(...)
       return repl
     endif
   endfor
+  if exists('*classpath#from_vim')
     let cp = classpath#from_vim(getbufvar(buf, '&path'))
     return extend({'classpath': cp}, s:oneoff)
+  endif
+  throw ':Connect to a REPL or install classpath.vim to evaluate code'
 endfunction
 
 function! s:output_response(response) abort
@@ -393,9 +388,63 @@ function! s:eval(expr, ...) abort
   return client.eval(a:expr, options)
 endfunction
 
+function! s:temp_response(response) abort
+  let output = []
+  if get(a:response, 'out', '') !=# ''
+    let output = map(split(a:response.out, "\n"), '";".v:val')
+  endif
+  if has_key(a:response, 'value')
+    let output += [a:response.value]
+  endif
+  let temp = tempname().'.clj'
+  call writefile(output, temp)
+  return temp
+endfunction
+
+if !exists('s:history')
+  let s:history = []
+endif
+
+if !exists('s:qffiles')
+  let s:qffiles = {}
+endif
+
+function! s:qfentry(entry) abort
+  if !has_key(a:entry, 'tempfile')
+    let a:entry.tempfile = s:temp_response(a:entry.response)
+  endif
+  let s:qffiles[a:entry.tempfile] = a:entry
+  return {'filename': a:entry.tempfile, 'text': a:entry.code}
+endfunction
+
+function! s:qfhistory() abort
+  let list = []
+  for entry in s:history
+    if !has_key(entry, 'tempfile')
+      let entry.tempfile = s:temp_response(entry.response)
+    endif
+    call extend(list, [s:qfentry(entry)])
+  endfor
+  return list
+endfunction
+
+function! s:previewwindow()
+  for nr in range(1, winnr('$'))
+    if getwinvar(nr, '&previewwindow')
+      return nr
+    endif
+  endfor
+endfunction
+
 function! foreplay#eval(expr) abort
   let response = s:eval(a:expr, {'session': 1})
 
+  call extend(s:history, [{'buffer': bufnr(''), 'code': a:expr, 'ns': foreplay#ns(), 'response': response}])
+  let pwin = s:previewwindow()
+  if pwin && has_key(s:qffiles, bufname(winbufnr(pwin)))
+    call setloclist(pwin, [s:qfentry(s:history[-1])], 'a')
+  endif
+
   call s:output_response(response)
 
   if get(response, 'ex', '') !=# ''
@@ -409,10 +458,25 @@ function! foreplay#eval(expr) abort
 endfunction
 
 function! foreplay#evalprint(expr) abort
+  let pwin = s:previewwindow()
+  if s:previewwindow()
+    try
+      silent call foreplay#eval(a:expr)
+    catch /^Clojure:/
+    endtry
+    let nr = winnr()
+    wincmd p
+    wincmd P
+    call setloclist(pwin, s:qfhistory())
+    llast
+    wincmd p
+    exe nr.'wincmd w'
+  else
     try
       echo foreplay#eval(a:expr)
     catch /^Clojure:/
     endtry
+  endif
   return ''
 endfunction
 
@@ -817,11 +881,13 @@ function! s:buffer_path(...) abort
     return ''
   endif
   let path = substitute(fnamemodify(bufname(buffer), ':p'), '\C^zipfile:\(.*\)::', '\1/', '')
+  if exists('*classpath#from_vim')
     for dir in classpath#split(classpath#from_vim(getbufvar(buffer, '&path')))
       if dir !=# '' && path[0 : strlen(dir)-1] ==# dir
         return path[strlen(dir)+1:-1]
       endif
     endfor
+  endif
   return ''
 endfunction