Split out filter native viml impl

CHANGELOG.md

@@ -8,6 +8,10 @@ CHANGELOG
 - Add `maple version` to get the detailed maple info and include it in `:Clap debug`.([#262](https://github.com/liuchengxu/vim-clap/pull/262))
 - Add `g:clap_forerunner_status_sign` and deprecate `g:clap_forerunner_status_sign_done` and `g:clap_forerunner_status_sign_running`.
 
+### Internal
+
+- Split out the native VimScript filter implementation in favor of the potential vim9 improvement.([#267](https://github.com/liuchengxu/vim-clap/pull/267))
+
 ### Changed
 
 - Use    as the icon of markdown.

autoload/clap/api.vim

@@ -234,7 +234,7 @@ function! s:init_display() abort
   " Optional argument: pattern to match
   " Default: input
   function! display.add_highlight(...) abort
-    let pattern = a:0 > 0 ? a:1 : clap#filter#matchadd_pattern()
+    let pattern = a:0 > 0 ? a:1 : clap#filter#viml#matchadd_pattern()
     if empty(pattern)
       return
     endif

autoload/clap/filter.vim

@@ -4,66 +4,13 @@
 let s:save_cpo = &cpoptions
 set cpoptions&vim
 
-let s:pattern_builder = {}
-
 if has('python3') || has('python')
   let s:py_exe = has('python3') ? 'python3' : 'python'
   let s:pyfile = has('python3') ? 'py3file' : 'pyfile'
 else
   let s:py_exe = v:null
 endif
 
-function! s:pattern_builder._force_case() abort
-  " Smart case
-  if self.input =~? '\u'
-    return '\C'
-  else
-    return '\c'
-  endif
-endfunction
-
-function! s:pattern_builder.smartcase() abort
-  let l:_force_case = self._force_case()
-  let s:matchadd_pattern = l:_force_case.self.input
-  return l:_force_case.self.input
-endfunction
-
-function! s:pattern_builder.substring() abort
-  let l:_force_case = self._force_case()
-  let l:filter_pattern = ['\V\^', l:_force_case]
-  let s:matchadd_pattern = []
-  for l:s in split(self.input)
-    call add(filter_pattern, printf('\.\*\zs%s\ze', l:s))
-    " FIXME can not distinguish `f f` highlight
-    " these two f should be highlighed with different colors
-    call add(s:matchadd_pattern, l:_force_case.l:s)
-  endfor
-  return join(l:filter_pattern, '')
-endfunction
-
-function! s:pattern_builder.build() abort
-  if stridx(self.input, ' ') != -1
-    return self.substring()
-  else
-    return self.smartcase()
-  endif
-endfunction
-
-" Return substring pattern or the smartcase input pattern.
-function! clap#filter#matchadd_pattern() abort
-  return get(s:, 'matchadd_pattern', '')
-endfunction
-
-function! s:filter(line, pattern) abort
-  return a:line =~ a:pattern
-endfunction
-
-function! s:fallback_filter(query, candidates) abort
-  let s:pattern_builder.input = a:query
-  let l:filter_pattern = s:pattern_builder.build()
-  return filter(copy(a:candidates), 's:filter(v:val, l:filter_pattern)')
-endfunction
-
 let s:can_use_python = v:false
 let s:has_py_dynamic_module = v:false
 
@@ -137,12 +84,12 @@ if s:can_use_python
       return s:ext_filter(a:query, a:candidates)
     catch
       call clap#helper#echo_error(v:exception)
-      return s:fallback_filter(a:query, a:candidates)
+      return clap#filter#viml#(a:query, a:candidates)
     endtry
   endfunction
 else
   function! clap#filter#(query, candidates) abort
-    return s:fallback_filter(a:query, a:candidates)
+    return clap#filter#viml#(a:query, a:candidates)
   endfunction
 endif
 

autoload/clap/filter/viml.vim

@@ -0,0 +1,62 @@
+" Author: liuchengxu <xuliuchengxlc@gmail.com>
+" Description: Native VimL implementation of filter.
+" Used when there is no +python3 and external binary.
+
+let s:save_cpo = &cpoptions
+set cpoptions&vim
+
+let s:pattern_builder = {}
+
+function! s:pattern_builder._force_case() abort
+  " Smart case
+  if self.input =~? '\u'
+    return '\C'
+  else
+    return '\c'
+  endif
+endfunction
+
+function! s:pattern_builder.smartcase() abort
+  let l:_force_case = self._force_case()
+  let s:matchadd_pattern = l:_force_case.self.input
+  return l:_force_case.self.input
+endfunction
+
+function! s:pattern_builder.substring() abort
+  let l:_force_case = self._force_case()
+  let l:filter_pattern = ['\V\^', l:_force_case]
+  let s:matchadd_pattern = []
+  for l:s in split(self.input)
+    call add(filter_pattern, printf('\.\*\zs%s\ze', l:s))
+    " FIXME can not distinguish `f f` highlight
+    " these two f should be highlighed with different colors
+    call add(s:matchadd_pattern, l:_force_case.l:s)
+  endfor
+  return join(l:filter_pattern, '')
+endfunction
+
+function! s:pattern_builder.build() abort
+  if stridx(self.input, ' ') != -1
+    return self.substring()
+  else
+    return self.smartcase()
+  endif
+endfunction
+
+function! s:filter(line, pattern) abort
+  return a:line =~ a:pattern
+endfunction
+
+" Return substring pattern or the smartcase input pattern.
+function! clap#filter#viml#matchadd_pattern() abort
+  return get(s:, 'matchadd_pattern', '')
+endfunction
+
+function! clap#filter#viml#(query, candidates) abort
+  let s:pattern_builder.input = a:query
+  let l:filter_pattern = s:pattern_builder.build()
+  return filter(copy(a:candidates), 's:filter(v:val, l:filter_pattern)')
+endfunction
+
+let &cpoptions = s:save_cpo
+unlet s:save_cpo