refactored again; s:BuildTabStops() may actually be somewhat comprehensible now

after/plugin/snipMate.vim

@@ -32,3 +32,4 @@ fun s:GetSnippets()
 		endif
 	endfor
 endf
+" vim:noet:sw=4:ts=4:ft=vim

plugin/snipMate.vim

@@ -26,7 +26,7 @@ fun! Filename(...)
 	return !a:0 || a:1 == '' ? filename : substitute(a:1, '$1', filename, 'g')
 endf
 
-" escapes special characters in snippet triggers
+" Escapes special characters in snippet triggers
 fun s:Hash(text)
 	return substitute(a:text, '\W', '\="_".char2nr(submatch(0))."_"', 'g')
 endf
@@ -44,7 +44,7 @@ fun s:MakeSnippet(text, ft, multisnip)
 		let var = 's:snippets'
 	endif
 	if !has_key({var}, a:ft) | let {var}[a:ft] = {} | endif
-	let end = strpart(a:text, space+1)
+	let end = strpart(a:text, space + 1)
 
 	if end == '' || space == '' || (a:multisnip && name == '')
 		echom 'Error in snipMate.vim: Snippet '.a:text.' is undefined.'
@@ -59,25 +59,24 @@ fun s:MakeSnippet(text, ft, multisnip)
 endf
 
 fun! ExtractSnips(dir, ft)
-	let s:slash = has('win16') || has('win32') || has('win64') ? '\\' : '/'
+	let slash = has('win16') || has('win32') || has('win64') ? '\\' : '/'
 	for path in split(globpath(a:dir, '*'), "\n")
 		if isdirectory(path)
 			for snipFile in split(globpath(path, '*.snippet'), "\n")
 				call s:ProcessFile(snipFile, a:ft,
-									\ strpart(path, strridx(path, s:slash)+1))
+								\ strpart(path, strridx(path, slash)+1, slash))
 			endfor
 		else
-			call s:ProcessFile(path, a:ft)
+			call s:ProcessFile(path, a:ft, slash)
 		endif
 	endfor
-	unl s:slash
 	let g:did_ft_{a:ft} = 1
 endf
 
 " Processes a snippet file; optionally add the name of the parent directory
 " for a snippet with multiple matches.
-fun s:ProcessFile(file, ft, ...)
-	let keyword = matchstr(a:file, '.*'.s:slash.'\zs.*\ze\.snippet')
+fun s:ProcessFile(file, ft, slash, ...)
+	let keyword = matchstr(a:file, '.*'.a:slash.'\zs.*\ze\.snippet')
 	if keyword  == '' | return | endif
 	try
 		let text = join(readfile(a:file), "\n")
@@ -109,7 +108,7 @@ fun s:ChooseSnippet(ft, trigger)
 endf
 
 fun! TriggerSnippet()
-	if pumvisible() " update snippet if completion is used, or deal with supertab
+	if pumvisible() " Update snippet if completion is used, or deal with supertab
 		if exists('s:sid') | return "\<c-n>" | endif
 		call feedkeys("\<esc>a", 'n') | call s:UpdateChangedSnip(0)
 	endif
@@ -119,18 +118,18 @@ fun! TriggerSnippet()
 	endif
 
 	if exists('s:snipPos') && s:endSnip == s:snipPos[s:curPos][1]+s:snipPos[s:curPos][2]
-		return s:JumpTabStop() " don't treat placeholder text as a trigger
+		return s:JumpTabStop() " Don't treat placeholder text as a trigger.
 	endif
 
 	let word = matchstr(getline('.'), '\S\+\%'.col('.').'c')
-	for filetype in split(&ft, '\.') + ['_'] " deal with dotted file-types
+	for filetype in split(&ft, '\.') + ['_'] " Deal with dotted file-types
 		let trigger = s:GetSnippet(word, filetype)
 		if exists('s:snippet') | break | endif
 	endfor
 
-	" if word is a trigger for a snippet, delete the trigger & expand the snippet
+	" If word is a trigger for a snippet, delete the trigger & expand the snippet.
 	if exists('s:snippet')
-		if s:snippet == '' " if user cancelled a multi snippet, quit
+		if s:snippet == '' " If user cancelled a multi snippet, quit.
 			return unl s:snippet
 		endif
 		let col = col('.') - len(trigger)
@@ -141,6 +140,13 @@ fun! TriggerSnippet()
 	return exists('s:sid') ? {s:sid}_SuperTab('n') : "\<tab>"
 endf
 
+fun s:GetSuperTabSID()
+	let old = @a
+	redir @a | exe 'sil fun /SuperTab$' | redir END
+	let s:sid = matchstr(@a, '<SNR>\d\+\ze_SuperTab(command)')
+	let @a = old
+endf
+
 " Check if word under cursor is snippet trigger; if it isn't, try checking if
 " the text after non-word characters is (e.g. check for "foo" in "bar.foo")
 fun s:GetSnippet(word, ft)
@@ -159,49 +165,45 @@ fun s:GetSnippet(word, ft)
 	return origWord
 endf
 
-fun s:GetSuperTabSID()
-	let old = @a
-	redir @a | exe 'sil fun /SuperTab$' | redir END
-	let s:sid = matchstr(@a, '<SNR>\d\+\ze_SuperTab(command)')
-	let @a = old
-endf
-
 fun s:ExpandSnippet(col)
 	let lnum = line('.') | let col = a:col
-	let afterCursor = strpart(getline('.'), col-1)
-	if afterCursor != "\t" && afterCursor != ' '
-		sil exe 's/\%'.col.'c.*//'
-	else | let afterCursor = '' | endif
-
-	" for some reason the cursor needs to move one right after this
-	let line = getline(lnum)
-	if line != '' && col == 1 && afterCursor == '' && &ve !~ 'all\|onemore'
-		let col += 1
-	endif
 
 	call s:ProcessSnippet()
 	if s:snippet == ''
-		return unl s:snippet " avoid an error if the snippet is now empty
+		return unl s:snippet " Avoid an error if the snippet is now empty
 	endif
 
 	let snip = split(substitute(s:snippet, '$\d\|${\d.\{-}}', '', 'g'), "\n", 1)
-	if afterCursor != '' | let snip[-1] .= afterCursor | endif
-	call setline(lnum, line.snip[0])
 
-	" autoindent snippet according to previous indentation
-	let indent = matchend(line, '^.\{-}\ze\(\S\|$\)')+1
-	call append(lnum, map(snip[1:], "'".strpart(line, 0, indent-1)."'.v:val"))
-
-	if exists('s:snipPos') && stridx(s:snippet, '${1') != -1
-		if exists('s:update')
-			call s:UpdateSnip(len(snip[-1])-len(afterCursor))
-			call s:UpdatePlaceholderTabStops()
-		else
-			call s:UpdateTabStops(len(snip)-1, len(snip[-1])-len(afterCursor))
+	let afterCursor = strpart(getline('.'), col-1)
+	if afterCursor != "\t" && afterCursor != ' '
+		sil exe 's/\%'.col.'c.*//'
+		let snip[-1] .= afterCursor
+	else
+		let afterCursor = ''
+		" For some reason the cursor needs to move one right after this
+		if getline(lnum) != '' && col == 1 && &ve !~ 'all\|onemore'
+			let col += 1
 		endif
 	endif
 
-	let snipLen = s:BuildTabStops(lnum, col-indent, indent)
+	let line = getline(lnum)
+	call setline(lnum, line.snip[0])
+
+	" Autoindent snippet according to previous indentation
+	let indent = matchend(line, '^.\{-}\ze\(\S\|$\)') + 1
+	call append(lnum, map(snip[1:], "'".strpart(line, 0, indent - 1)."'.v:val"))
+
+	if exists('s:snipPos') && stridx(s:snippet, '${1') != -1
+		if exists('s:update')
+			call s:UpdateSnip(len(snip[-1]) - len(afterCursor))
+			call s:UpdatePlaceholderTabStops()
+		else
+			call s:UpdateTabStops(len(snip) - 1, len(snip[-1]) - len(afterCursor))
+		endif
+	endif
+
+	let snipLen = s:BuildTabStops(lnum, col - indent, indent)
 	unl s:snippet
 
 	if snipLen
@@ -218,17 +220,17 @@ fun s:ExpandSnippet(col)
 		if s:snipPos[s:curPos][2] != -1 | return s:SelectWord() | endif
 	else
 		if !exists('s:snipLen') | unl s:snipPos | endif
-		" place cursor at end of snippet if no tab stop is given
-		let newlines = len(snip)-1
+		" Place cursor at end of snippet if no tab stop is given
+		let newlines = len(snip) - 1
 		call cursor(lnum + newlines, indent + len(snip[-1]) - len(afterCursor)
-					\ + (newlines ? 0: col-1))
+					\ + (newlines ? 0: col - 1))
 	endif
 	return ''
 endf
 
 fun s:ProcessSnippet()
-	" evaluate eval (`...`) expressions
-	" Using a loop here instead of a regex fixes a bug with nested "\="
+	" Evaluate eval (`...`) expressions
+	" Using a loop here instead of a regex fixes a bug with nested "\=".
 	if stridx(s:snippet, '`') != -1
 		wh match(s:snippet, '`.\{-}`') != -1
 			let s:snippet = substitute(s:snippet, '`.\{-}`',
@@ -238,12 +240,12 @@ fun s:ProcessSnippet()
 		let s:snippet = substitute(s:snippet, "\r", "\n", 'g')
 	endif
 
-	" place all text after a colon in a tab stop after the tab stop
+	" Place all text after a colon in a tab stop after the tab stop
 	" (e.g. "${#:foo}" becomes "${:foo}foo")
-	" this helps tell the position of the tab stops later.
+	" This helps tell the position of the tab stops later.
 	let s:snippet = substitute(s:snippet, '${\d:\(.\{-}\)}', '&\1', 'g')
 
-	" update the s:snippet so that all the $# become
+	" Update the s:snippet so that all the $# become
 	" the text after the colon in their associated ${#}
 	" (e.g. "${1:foo}" turns all "$1"'s into "foo")
 	let i = 1
@@ -255,7 +257,7 @@ fun s:ProcessSnippet()
 		let i += 1
 	endw
 
-	if &et " expand tabs to spaces if 'expandtab' is set
+	if &et " Expand tabs to spaces if 'expandtab' is set.
 		let s:snippet = substitute(s:snippet, '\t',
 						\ repeat(' ', &sts ? &sts : &sw), 'g')
 	endif
@@ -271,55 +273,52 @@ fun s:Count(haystack, needle)
 	return counter
 endf
 
-" Sorry, this next function is a bit convoluted...
-" This function builds a list of a list of each tab stop in the snippet
-" containing:
-" 1.) The number of the current line plus the number of "\n"s (line
-" breaks) before the tab stop
-" 2.) The current column plus the position of the next "${#}" on
-" the line by getting the length of the string between the last "\n"
-" and the "${#}" tab stop,
+" This function builds a list of a list of each tab stop in the
+" snippet containing:
+" 1.) The tab stop's line number.
+" 2.) The tab stop's column number
+"     (by getting the length of the string between the last "\n" and the
+"     tab stop).
 " 3.) The length of the text after the colon for the current tab stop
-" (e.g. "${#:foo}" would returnrn 3). If there is no text, -1 is returnrned.
-" 4.) If the "${#:}" construct is given, the fourth part of the list
-" is another list containing all the matches of "$#", to be replaced
-" with the variable. This list is composed the same way as the parent:
-" the first part is the number of "\n"s before the tab stop, and
-" second is the position (column) of the "$#" tab stop on the line.
-" If there are none of these tab stop, an empty list ([]) is returnrned
+"     (e.g. "${1:foo}" would return 3). If there is no text, -1 is returned.
+" 4.) If the "${#:}" construct is given, another list containing all
+"     the matches of "$#", to be replaced with the placeholder. This list is
+"     composed the same way as the parent; the first item is the line number,
+"     and the second is the column.
 fun s:BuildTabStops(lnum, col, indent)
-	let snipPos = [] | let i = 1
-	" temporarily delete placeholders
-	let cut_snip = substitute(s:snippet, '$\d', '', 'g')
+	let snipPos = []
+	let i = 1
 	wh stridx(s:snippet, '${'.i) != -1
-		let snipPos += [[a:lnum+s:Count(matchstr(cut_snip, '^.*\ze${'.i), "\n"),
-				\ a:indent+len(matchstr(substitute(cut_snip, '${'.i.'\@!\d.\{-}}', '', 'g'),
-				\ "^.*\\(\n\\|^\\)\\zs.*\\ze${".i.'.\{-}}')), -1]]
+		let beforeTabStop = matchstr(s:snippet, '^.*\ze${'.i)
+		let withoutOthers = substitute(s:snippet, '$\d\|${'.i.'\@!\d.\{-}}', '', 'g')
+		let snipPos += [[a:lnum + s:Count(beforeTabStop, "\n"),
+						\ a:indent + len(matchstr(withoutOthers,
+						\ "^.*\\(\n\\|^\\)\\zs.*\\ze${".i)), -1]]
 		if snipPos[i-1][0] == a:lnum
 			let snipPos[i-1][1] += a:col
 		endif
 
-		" get all $# matches in another list, if ${#:name} is given
-		if stridx(cut_snip, '${'.i.':') != -1
+		" Get all $# matches in another list, if ${#:name} is given
+		if stridx(s:snippet, '${'.i.':') != -1
 			let j = i-1
-			let snipPos[j][2] = len(matchstr(cut_snip, '${'.i.':\zs.\{-}\ze}'))
+			let snipPos[j][2] = len(matchstr(s:snippet, '${'.i.':\zs.\{-}\ze}'))
 			let snipPos[j] += [[]]
-			" temporarily delete all other tab stops/placeholders
-			let tempstr = substitute(s:snippet, '$'.i.'\@!\d\|${\d.\{-}}', '', 'g')
-			wh stridx(tempstr, '$'.i) != -1
-				let beforeMark = matchstr(tempstr, '^.\{-}\ze$'.i)
-				let linecount = a:lnum+s:Count(beforeMark, "\n")
+			let withoutOthers = substitute(s:snippet, '${\d.\{-}}\|$'.i.'\@!\d', '', 'g')
+			wh stridx(withoutOthers, '$'.i) != -1
+				let beforeMark = matchstr(withoutOthers, '^.\{-}\ze$'.i)
+				let linecount = a:lnum + s:Count(beforeMark, "\n")
 				let snipPos[j][3] += [[linecount,
-							\ a:indent+(linecount > a:lnum ?
-							\ len(matchstr(beforeMark, "^.*\n\\zs.*"))
-							\ : a:col+len(beforeMark))]]
-				let tempstr = substitute(tempstr, '$'.i, '', '')
+							\ a:indent + (linecount > a:lnum
+							\ ? len(matchstr(beforeMark, "^.*\n\\zs.*"))
+							\ : a:col + len(beforeMark))]]
+				let withoutOthers = substitute(withoutOthers, '$'.i, '', '')
 			endw
 		endif
 		let i += 1
 	endw
-	if exists('s:snipPos') " allow nested snippets
-		let s:snipPos = extend(s:snipPos, snipPos, s:curPos+1)
+
+	if exists('s:snipPos') " Build a nested snippet
+		let s:snipPos = extend(s:snipPos, snipPos, s:curPos + 1)
 	else
 		let s:snipPos = snipPos
 	endif
@@ -350,7 +349,7 @@ fun s:JumpTabStop()
 endf
 
 fun s:UpdatePlaceholderTabStops()
-	" update tab stops in snippet if text has been added via "$#",
+	" Update tab stops in snippet if text has been added via "$#",
 	" e.g. in "${1:foo}bar$1${2}"
 	if exists('s:origPos')
 		let changeLen = s:origWordLen - s:snipPos[s:curPos][2]
@@ -359,15 +358,15 @@ fun s:UpdatePlaceholderTabStops()
 		if changeLen != 0
 			let lnum = line('.')
 			let len = len(s:origPos)
-			for pos in s:snipPos[(s:curPos+1):]
+			for pos in s:snipPos[(s:curPos + 1):]
 				let i = 0 | let j = 0 | let k = 0
-				let endSnip = pos[2]+pos[1]-1
+				let endSnip = pos[2] + pos[1] - 1
 				wh i < len && s:origPos[i][0] <= pos[0]
 					if pos[0] == s:origPos[i][0]
 						if pos[1] > s:origPos[i][1]
-									\ || (pos[2] == -1 && pos[1] == s:origPos[i][1])
+								\ || (pos[2] == -1 && pos[1] == s:origPos[i][1])
 							let j += 1
-						elseif s:origPos[i][1] < endSnip " parse variables within placeholders
+						elseif s:origPos[i][1] < endSnip " Parse variables within placeholders
 							let k += 1
 						endif
 					endif
@@ -408,13 +407,13 @@ fun s:UpdateTabStops(...)
 	if exists('s:origWordLen')
 		let changeCol -= s:origWordLen | unl s:origWordLen
 	endif
-	" there's probably a more efficient way to do this as well...
+	" There's probably a more efficient way to do this as well...
 	let lnum = s:snipPos[s:curPos][0]
 	let col  = s:snipPos[s:curPos][1]
-	" update the line number of all proceeding tab stops if <cr> has
-	" been inserted
+	" Update the line number of all proceeding tab stops if <cr> has
+	" been inserted.
 	if changeLine != 0
-		for pos in s:snipPos[(s:curPos+1):]
+		for pos in s:snipPos[(s:curPos + 1):]
 			if pos[0] >= lnum
 				if pos[0] == lnum
 					let pos[1] += changeCol
@@ -433,9 +432,9 @@ fun s:UpdateTabStops(...)
 			endif
 		endfor
 	elseif changeCol != 0
-		" update the column of all proceeding tab stops if text has
-		" been inserted/deleted in the current line
-		for pos in s:snipPos[(s:curPos+1):]
+		" Update the column of all proceeding tab stops if text has
+		" been inserted/deleted in the current line.
+		for pos in s:snipPos[(s:curPos + 1):]
 			if pos[1] >= col && pos[0] == lnum
 				let pos[1] += changeCol
 			endif
@@ -482,10 +481,10 @@ au CursorMovedI * call s:UpdateChangedSnip(0)
 au InsertEnter * call s:UpdateChangedSnip(1)
 fun s:UpdateChangedSnip(entering)
 	if exists('s:update')
-		if !exists('s:origPos') && s:curPos+1 < s:snipLen
-			" save the old snippet & word length before it's updated
+		if !exists('s:origPos') && s:curPos + 1 < s:snipLen
+			" Save the old snippet & word length before it's updated
 			" s:startSnip must be saved too, in case text is added
-			" before the snippet (e.g. in "foo$1${2}bar${1:foo}")
+			" before the snippet (e.g. in "foo$1${2}bar${1:foo}").
 			let s:origSnipPos = s:startSnip
 			let s:origPos     = deepcopy(s:snipPos[s:curPos][3])
 		endif
@@ -494,12 +493,12 @@ fun s:UpdateChangedSnip(entering)
 		if s:endSnip != -1
 			let changeLen = col('$') - s:prevLen[1]
 			let s:endSnip += changeLen
-		else " when being updated the first time, after leaving select mode
+		else " When being updated the first time, after leaving select mode
 			if a:entering | return | endif
 			let s:endSnip = col-1
 		endif
 
-		" if the cursor moves outside the snippet, quit it
+		" If the cursor moves outside the snippet, quit it
 		if line('.') != s:snipPos[s:curPos][0] || col < s:startSnip ||
 					\ col-1 > s:endSnip
 			unl! s:startSnip s:origWordLen s:origPos s:update
@@ -522,7 +521,7 @@ fun s:UpdateChangedSnip(entering)
 			let s:endSnip = col
 		endif
 
-		" delete snippet if cursor moves out of it in insert mode
+		" Delete snippet if cursor moves out of it in insert mode
 		if (lnum == s:endSnipLine && (col > s:endSnip || col < s:snipPos[s:curPos][1]))
 			\ || lnum > s:endSnipLine || lnum < s:snipPos[s:curPos][0]
 			call s:RemoveSnippet()
@@ -531,7 +530,7 @@ fun s:UpdateChangedSnip(entering)
 endf
 
 fun s:UpdateSnip(...)
-	" using strpart() here avoids a bug if s:endSnip is negative that would
+	" Using strpart() here avoids a bug if s:endSnip was negative that would
 	" happen with the getline('.')[(s:startSnip):(s:endSnip)] syntax
 	let newWordLen = a:0 ? a:1 : s:endSnip - s:startSnip + 1
 	let newWord    = strpart(getline('.'), s:startSnip, newWordLen)