Tip #277: Function signature previewer

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Rating 19/6, Viewed by 1161

created:		July 6, 2002 18:28		complexity:		basic
author:		Georgi Slavchev [email protected]		as of Vim:		6.0

Have you ever tried to call a function which parameters you have forgotten? Especially those long named and with long parameter list GTK+ functions like gtk_menu_item_image_from_stock_new(..........) !!! By accident I saw a function in Vim help. It's name was PreviewWord and it allowed one to jump in the preview window to the tag for the word cursor is on. I _slightly_ modified this function not to need tags file, but to search included files instead. I wrote another function, which uses the above said one, which triggers PreviewWord when you open the parenthesis after a function name. Here it is: " Note: " This is literally stolen from Vim help. The only changes are: " (1) if w != "" becomes if w =~ "\k" " (2) exe "silent! ptag " . w becomes exe "silent! psearch " . w " * The first change prevents PreviewWord of searching while cursor is on some " non-keyword characters, e.g. braces, asterisks, etc. function! PreviewWord() if &previewwindow; " don't do this in the preview window return endif let w = expand("<cword>") " get the word under cursor if w =~ "\k" " if there is one ":ptag" to it " Delete any existing highlight before showing another tag silent! wincmd P " jump to preview window if &previewwindow; " if we really get there... match none " delete existing highlight wincmd p " back to old window endif " Try displaying a matching tag for the word under the cursor let v:errmsg = "" exe "silent! psearch " . w if v:errmsg =~ "tag not found" return endif silent! wincmd P " jump to preview window if &previewwindow; " if we really get there... if has("folding") silent! .foldopen " don't want a closed fold endif call search("$", "b") " to end of previous line let w = substitute(w, '\', '\\\', "") call search('\<\V' . w . '\>') " position cursor on match " Add a match highlight to the word at this position hi previewWord term=bold ctermbg=green guibg=green exe 'match previewWord "\%' . line(".") . 'l\%' . col(".") . 'c\k*"' wincmd p " back to old window endif endif endfunction au! CursorHold *.[ch] nested call PreviewWord() " Note: " When you open a parenthesis after a function name, and at the " line end, that function's definition is previewed through PreviewWord(). " This is inspired from Delphi's CodeInsight technology. " Something similar (PreviewClassMembers) could be written for " the C++ users, for previewing the class members when you type " a dot after an object name. " If somebody decides to write it, please, mail it to me. function! PreviewFunctionSignature() let CharOnCursor = strpart( getline('.'), col('.')-2, 1) if col(".") == col("$") call PreviewWord() endif return "(" endfunction inoremap <buffer> ( <C-R>=PreviewFunctionSignature()<LF>

<<Function signature previewer | all the right moves >>

Additional Notes

[email protected], September 19, 2002 0:21

There is an error in PreviewWord function. You have to replace line 12 with this: if w =~ "\i" " if there is one ":psearch" to it You may also have to convert the fileformat from "dos" to "unix" if you have downloaded the source under a windoze browser: :set fileformat=unix If you want to search in certain dirs, you have to specify them in the .vim file, like this: setlocal path+=/usr/include/gtk-1.2/** setlocal path+=/usr/include/gnome-1.0/** Thanks to Balaji V T for the bug-report.

[email protected], December 26, 2002 4:46

I like this tip very much :) However, I don't know why this script doesn't work So I modify some lines make it work for me And let it try ptag first, then psearch It also avoid previewing some C keyword like for, while, double, etc. " Note: " This is literally stolen from Vim help. The only changes are: " (1) if w != "" becomes if w =~ "\k" " (2) exe "silent! ptag " . w becomes exe "silent! psearch " . w " * The first change prevents PreviewWord of searching while cursor is on some " non-keyword characters, e.g. braces, asterisks, etc. function! PreviewWord() if &previewwindow; " don't do this in the preview window return endif let w = expand("<cword>") " get the word under cursor if w =~ '\i' if w =~ '\<\v(for|while|if|else|continue|switch|return|break|case)\m\>' return endif if w =~ '\<\v(int|char|double|long|static|unsigned|const|void|define|undef)\m\>' return endif " if there is one ":ptag" to it " Delete any existing highlight before showing another tag silent! wincmd P " jump to preview window if &previewwindow; " if we really get there... match none " delete existing highlight wincmd p " back to old window endif " Try displaying a matching tag for the word under the cursor let v:errmsg = "" exe "silent! ptag " . w if v:errmsg =~ "tag not found" exe "silent! psearch " . w endif silent! wincmd P " jump to preview window if &previewwindow; " if we really get there... if has("folding") silent! .foldopen " don't want a closed fold endif call search("$", "b") " to end of previous line let w = substitute(w, '', '\\', "") call search('\<\V' . w . '\>') " position cursor on match " Add a match highlight to the word at this position hi previewWord term=bold ctermbg=green guibg=green exe 'match previewWord "\%' . line(".") . 'l\%' . col(".") . 'c\k*"' wincmd p " back to old window endif endif endfunction " Note: " When you open a parenthesis after a function name, and at the " line end, that function's definition is previewed through PreviewWord(). " This is inspired from Delphi's CodeInsight technology. " Something similar (PreviewClassMembers) could be written for " the C++ users, for previewing the class members when you type " a dot after an object name. " If somebody decides to write it, please, mail it to me. function! PreviewFunctionSignature() let CharOnCursor = strpart( getline('.'), col('.')-2, 1) if col(".") == col("$")-1 normal h call PreviewWord() normal l endif endfunction function Register(...) let index=1 while index <= a:0 execute 'let ext=a:'.index execute 'au! CursorHold '.ext.' nested call PreviewWord()' execute 'au BufNewFile,BufRead '.ext.' nested inoremap <buffer> ( <Esc>:call PreviewFunctionSignature()<CR>a(' let index=index+1 endwhile endf call Register('*.[ch]', '*.cc', '*.cpp') call Register('*.[ch]0','*.cc0','*.cpp0')




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