How can I get vim to include suffixes in <cfile>?

Question

In part of a plugin I'm slowly building, I use <cfile> to get the file pointed by the word under the cursor and then do something if it points to a directory, or open the file pointed to otherwise (so unless the word under the cursors points to a directory, it's supposed to behave exactly like gf). It all works fine, except for suffixes.

help <cfile> in vim says:

<cfile> is replaced with the path name under the cursor (like what gf uses)

but while gf will include a possibly auto-detected suffix, this doesn't seem to be the case in <cfile>. Is there some kind of workaround for this?

In case it helps clarify my question, here's the relevant code excerpt:

  1 function! now#BufEnter() "{{{                                          
  2 " behaviour of <enter> while on now files (mapped on ftplugin)         
  3   execute "silent! normal! :set suffixesadd=" . g:NOW_suffix . "\r"    
  4   let l:dest = expand("<cfile>")                                       
  5   if isdirectory(l:dest)                                               
  6     " if pointing to a directory, update and enter index file there    
  7     execute 'normal! :cd ' . l:dest . "\r"                             
  8     call now#MakeIndex()                                               
  9   else                                                                 
 10     " otherwise edit the file, whether it exists or not                
 11     execute 'normal! :e ' . l:dest . "\r"                              
 12   endif                                                                
 13 endfunction "}}}

Line 3 was added for debugging purposes only, copied from elsewhere. The added suffix is flawlessly detected by gf, but not with the keymap pointing towards the above function (as the comments in the code mention, it is the <enter> key). When no suffix is needed, the code works as expected: do the directory stuff if need, or edit the pointed file, creating it if necessary.

Answer 1

Prompted by the comment fron @VanLaser, I thought it may be possible to somehow discriminate the behaviour with an if filereadable() to decide whether invoking a regular gf or an :edit in order to work around the limitations of <cfile>. However, there's a catch: I don't know which file to seek for readability before invoking gf. So finally, after trying a bit, here's a solution... with a catch.

 1 function! now#BufEnter() "{{{
 2 " behaviour of <enter> while on now files (mapped on ftplugin)
 3   execute "silent! normal! :set suffixesadd=" . g:NOW_suffix . "\r"
 4   let l:dest = expand("<cfile>")
 5   if isdirectory(l:dest)
 6     " if pointing to a directory, update and enter index file there
 7     execute 'normal! :cd ' . l:dest . "\r"
 8     call now#MakeIndex()
 9   else
10     " otherwise edit the file, whether it exists or not
11     " N.B: this is a bit tricky, because <cfile> does not detect an optional
12     " suffix, as discussed in the following Q/A topic:
13     " https://vi.stackexchange.com/q/9627/2058
14     try
15       " if a file can be found, with optional suffix, open it
16       normal gf
17     catch
18       " otherwise, create the file pointed to
19       execute 'normal! :e ' . l:dest . "\r"
20     endtry
21   endif
22 endfunction "}}}

A nice side-effect of this is being able to actually add a specific suffix upon creation (not shown in above code, which, for reference, is only trying to modify the question's code enough to answer the actual question).