More flexible file naming (Request #2)

CHG: More flexible file naming files matching one of the following are todo
files:
    YYYY-MM-[Tt]odo.txt
    YYYY-MM-DD[Tt]odo.txt
    [Tt]odo-YYYY-MM.txt
    [Tt]odo-YYYY-MM-DD.txt
    [Tt]odo.txt
    [Tt]oday.txt
    YYYY-MM-[Dd]one.txt
    YYYY-MM-DD[Dd]one.txt
    [Dd]one-YYYY-MM.txt
    [Dd]one-YYYY-MM-DD.txt
    [Dd]one.txt
    [Dd]one-[Tt]oday.txt
 Moreover, remove complete tasks (<LocalLeader>D) moves the task to the
 done.txt file corresponding to the current todo.txt, aka if you are editing
 2015-07-07-todo.txt, the done file while be 2015-07-07-done.txt.
 This behaviour can be cancelled by fixing the done filename using
 g:TodoTxtForceDoneName
FIX: Bug while completing empty file

ftplugin/todo.vim

@@ -65,7 +65,13 @@ endfunction
 
 function! TodoTxtRemoveCompleted()
     " Check if we can write to done.txt before proceeding.
-    let l:target_dir = expand('%:p:h')
+    let l:target_dir = expand('%:p:h')
+    if exists("g:TodoTxtForceDoneName")
+        let l:done=g:TodoTxtForceDoneName
+    else
+        let l:done=substitute(substitute(expand('%:t'),'todo','done',''),'Todo','Done','')
+    fi
+    let l:done_file = l:target_dir.'/'.l:done
     echo "Writing to ".l:done_file
     if !filewritable(l:done_file) && !filewritable(l:target_dir)
         echoerr "Can't write to file 'done.txt'"
@@ -79,7 +85,7 @@ endfunction
 
 function! TodoTxtSort()
     " vim :sort is usually stable
-    " we sort first on contexts, then on projects and then on priority
+    " we sort first on contexts, then on projects and then on priority
     if expand('%')=~'done.*.txt'
         silent! %s/\(x\s*\d\{4}\)-\(\d\{2}\)-\(\d\{2}\)/\1\2\3/g
         sort n /^x\s*/
@@ -277,20 +283,20 @@ endfunction
 endfunction
 
 " Simple keyword completion on all buffers
-function! TodoKeywordComplete(base)
-        " Search for matchs
-        let res = []
-        for bufnr in range(1,bufnr('$'))
-            let lines=getbufline(bufnr,1,"$")
-            for line in lines
-                if line =~ a:base
-                    " init temporary item
-                    let item={}
-                    let item.word=substitute(line,'.*\('.a:base.'\S*\).*','\1',"")
-                    call add(res,item)
-                endif
+function! TodoKeywordComplete(base)
+    " Search for matchs
+    let res = []
+    for bufnr in range(1,bufnr('$'))
+        let lines=getbufline(bufnr,1,"$")
+        for line in lines
+            if line =~ a:base
+                " init temporary item
+                let item={}
+                let item.word=substitute(line,'.*\('.a:base.'\S*\).*','\1',"")
+                call add(res,item)
             endif
-        endfor
+        endfor
+    endfor
     return res
 endfunction
 
@@ -326,33 +332,35 @@ fun! TodoComplete(findstart, base)
         endfor
         call sort(res)
         " Here all results are sorted in res, but we need to merge them
-        let ret=[]
-        let curitem={}
-        let curitem.word=res[0].word
-        let curitem.related=[]
-        let curitem.buffers=[]
-        for it in res
-            if curitem.word==it.word
-                " Merge results
-                if index(curitem.related,it.related) <0
+        let ret=[]
+        if res != []
+            let curitem={}
+            let curitem.word=res[0].word
+            let curitem.related=[]
+            let curitem.buffers=[]
+            for it in res
+                if curitem.word==it.word
+                    " Merge results
+                    if index(curitem.related,it.related) <0
+                        call add(curitem.related,it.related)
+                    endif
+                    if index(curitem.buffers,it.buffers) <0
+                        call add(curitem.buffers,it.buffers)
+                    endif
+                else
+                    " Create the definitive item
+                    let resitem={}
+                    let resitem.word=curitem.word
+                    let resitem.info=opp=='+'?"Projects":"Contexts"
+                    let resitem.info.=": ".join(curitem.related, ", ")
+                                \."\nBuffers: ".join(curitem.buffers, ", ")
+                    call add(ret,resitem)
+                    " Init new item from it
+                    let curitem.word=it.word
+                    let curitem.related=[it.related]
                     let curitem.buffers=[it.buffers]
-                endif
-                if index(curitem.buffers,it.buffers) <0
-                    call add(curitem.buffers,it.buffers)
-                endif
-            else
-                " Create the definitive item
-                let resitem={}
-                let resitem.word=curitem.word
-                let resitem.info=opp=='+'?"Projects":"Contexts"
-                let resitem.info.=": ".join(curitem.related, ", ")
-                            \."\nBuffers: ".join(curitem.buffers, ", ")
-                call add(ret,resitem)
-                " Init new item from it
-                let curitem.word=it.word
-                let curitem.related=[it.related]
-                let curitem.buffers=[it.buffers]
-            endif
+                endif
+            endfor
         endif
         return ret
     endif