Merge pull request python-mode#500 from wilywampa/nested_defs

Handle folding of nested defs correctly

autoload/pymode/folding.vim

@@ -76,6 +76,52 @@ fun! pymode#folding#expr(lnum) "{{{
         return "<".(indent / &shiftwidth + 1)
     endif
 
+    " Handle nested defs but only for files shorter than
+    " g:pymode_folding_nest_limit lines due to performance concerns
+    if line('$') < g:pymode_folding_nest_limit && indent(prevnonblank(a:lnum))
+        let curpos = getcurpos()
+        try
+            let last_block = s:BlockStart(a:lnum)
+            let last_block_indent = indent(last_block)
+
+            " Check if last class/def is not indented and therefore can't be
+            " nested.
+            if last_block_indent
+                call cursor(a:lnum, 0)
+                let next_def = searchpos(s:def_regex, 'nW')[0]
+                let next_def_indent = next_def ? indent(next_def) : -1
+                let last_block_end = s:BlockEnd(last_block)
+
+                " If the next def has greater indent than the previous def, it
+                " is nested one level deeper and will have its own fold. If
+                " the class/def containing the current line is on the first
+                " line it can't be nested, and if this block ends on the last
+                " line, it contains no trailing code that should not be
+                " folded. Finally, if the next non-blank line after the end of
+                " the previous def is less indented than the previous def, it
+                " is not part of the same fold as that def. Otherwise, we know
+                " the current line is at the end of a nested def.
+                if next_def_indent <= last_block_indent && last_block > 1 && last_block_end < line('$')
+                    \ && indent(nextnonblank(last_block_end)) >= last_block_indent
+
+                    " Include up to one blank line in the fold
+                    if getline(last_block_end) =~ s:blank_regex
+                        let fold_end = min([prevnonblank(last_block_end - 1), last_block_end]) + 1
+                    else
+                        let fold_end = last_block_end
+                    endif
+                    if a:lnum == fold_end
+                        return 's1'
+                    else
+                        return '='
+                    endif
+                endif
+            endif
+        finally
+            call setpos('.', curpos)
+        endtry
+    endif
+
     if line =~ s:blank_regex
         if prev_line =~ s:blank_regex
             if indent(a:lnum + 1) == 0 && getline(a:lnum + 1) !~ s:blank_regex
@@ -95,5 +141,36 @@ fun! pymode#folding#expr(lnum) "{{{
 
 endfunction "}}}
 
+fun! s:BlockStart(lnum) "{{{
+    " Note: Make sure to reset cursor position after using this function.
+    call cursor(a:lnum, 0)
+
+    " In case the end of the block is indented to a higher level than the def
+    " statement plus one shiftwidth, we need to find the indent level at the
+    " bottom of that if/for/try/while/etc. block.
+    let last_def = searchpos(s:def_regex, 'bcnW')[0]
+    if last_def
+        let last_def_indent = indent(last_def)
+        call cursor(last_def, 0)
+        let next_stmt_at_def_indent = searchpos('\v^\s{'.last_def_indent.'}[^[:space:]#]', 'nW')[0]
+    else
+        let next_stmt_at_def_indent = -1
+    endif
+
+    " Now find the class/def one shiftwidth lower than the start of the
+    " aforementioned indent block.
+    if next_stmt_at_def_indent && next_stmt_at_def_indent < a:lnum
+        let max_indent = max([indent(next_stmt_at_def_indent) - &shiftwidth, 0])
+    else
+        let max_indent = max([indent(prevnonblank(a:lnum)) - &shiftwidth, 0])
+    endif
+    return searchpos('\v^\s{,'.max_indent.'}(def |class )\w', 'bcnW')[0]
+endfunction "}}}
+
+fun! s:BlockEnd(lnum) "{{{
+    " Note: Make sure to reset cursor position after using this function.
+    call cursor(a:lnum, 0)
+    return searchpos('\v^\s{,'.indent('.').'}\S', 'nW')[0] - 1
+endfunction "}}}
 
 " vim: fdm=marker:fdl=0

plugin/pymode.vim

@@ -36,6 +36,8 @@ call pymode#default("g:pymode_indent", 1)
 
 " Enable/disable pymode folding for pyfiles.
 call pymode#default("g:pymode_folding", 1)
+" Maximum file length to check for nested class/def statements
+call pymode#default("g:pymode_folding_nest_limit", 1000)
 " Change for folding customization (by example enable fold for 'if', 'for')
 call pymode#default("g:pymode_folding_regex", '^\s*\%(class\|def\) \w\+')