Module:Wikitext Parsing
Documentation for this module may be created at Module:Wikitext Parsing/doc
-- From https://en.wikipedia.org/wiki/Module:Wikitext_Parsing
require("strict")
--Helper functions
local function startswith(text, subtext)
return string.sub(text, 1, #subtext) == subtext
end
local function endswith(text, subtext)
return string.sub(text, -#subtext, -1) == subtext
end
local function allcases(s)
return s:gsub("%a", function(c)
return "["..c:upper()..c:lower().."]"
end)
end
local trimcache = {}
local whitespace = {[" "]=1, ["\n"]=1, ["\t"]=1, ["\r"]=1}
local function cheaptrim(str) --mw.text.trim is surprisingly expensive, so here's an alternative approach
local quick = trimcache[str]
if quick then
return quick
else
-- local out = string.gsub(str, "^%s*(.-)%s*$", "%1")
local lowEnd
for i = 1,#str do
if not whitespace[string.sub(str, i, i)] then
lowEnd = i
break
end
end
if not lowEnd then
trimcache[str] = ""
return ""
end
for i = #str,1,-1 do
if not whitespace[string.sub(str, i, i)] then
local out = string.sub(str, lowEnd, i)
trimcache[str] = out
return out
end
end
end
end
--[=[ Implementation notes
---- NORMAL HTML TAGS ----
Tags are very strict on how they want to start, but loose on how they end.
The start must strictly follow <[tAgNaMe](%s|>) with no room for whitespace in
the tag's name, but may then flow as they want afterwards, making
<div\nclass\n=\n"\nerror\n"\n> valid
There's no sense of escaping < or >
E.g.
<div class="error\>"> will end at \> despite it being inside a quote
<div class="<span class="error">error</span>"> will not process the larger div
If a tag has no end, it will consume all text instead of not processing
---- NOPROCESSING TAGS (nowiki, pre, syntaxhighlight, source, etc.) ----
(In most comments, <source> will not be mentioned. This is because it is the
deprecated version of <syntaxhighlight>)
No-Processing tags have some interesting differences to the above rules.
For example, their syntax is a lot stricter. While an opening tag appears to
follow the same set of rules, A closing tag can't have any sort of extra
formatting period. While </div a/a> is valid, </nowiki a/a> isn't - only
newlines and spaces/tabs are allowed in closing tags.
Note that, even though <pre> tags cause a visual change when the ending tag has
extra formatting, it won't cause the no-processing effects. For some reason, the
format must be strict for that to apply.
Both the content inside the tag pair and the content inside each side of the
pair is not processed. E.g. <nowiki |}}>|}}</nowiki> would have both of the |}}
escaped in practice.
When something in the code is referenced to as a "Nowiki Tag", it means a tag
which causes wiki text to not be processed, which includes <nowiki>, <pre>,
and <syntaxhighlight>
Since we only care about these tags, we can ignore the idea of an intercepting
tag preventing processing, and just go straight for the first ending we can find
If there is no ending to find, the tag will NOT consume the rest of the text in
terms of processing behaviour (though <pre> will appear to have an effect).
Even if there is no end of the tag, the content inside the opening half will
still be unprocessed, meaning {{X20|<nowiki }}>}} wouldn't end at the first }}
despite there being no ending to the tag.
Note that there are some tags, like <math>, which also function like <nowiki>
which are included in this aswell. Some other tags, like <ref>, have far too
unpredictable behaviour to be handled currently (they'd have to be split and
processed as something seperate - its complicated, but maybe not impossible.)
I suspect that every tag listed in [[Special:Version]] may behave somewhat like
this, but that's far too many cases worth checking for rarely used tags that may
not even have a good reason to contain {{ or }} anyways, so we leave them alone.
---- HTML COMMENTS AND INCLUDEONLY ----
HTML Comments are about as basic as it could get for this
Start at <!--, end at -->, no extra conditions. Simple enough
If a comment has no end, it will eat all text instead of not being processed
includeonly tags function mostly like a regular nowiki tag, with the exception
that the tag will actually consume all future text if not given an ending as
opposed to simply giving up and not changing anything. Due to complications and
the fact that this is far less likely to be present on a page, aswell as being
something that may not want to be escaped, includeonly tags are ignored during
our processing
--]=]
local validtags = {nowiki=1, pre=1, syntaxhighlight=1, source=1, math=1}
--This function expects the string to start with the tag
local function TestForNowikiTag(text, scanPosition)
local tagName = (string.match(text, "^<([^\n />]+)", scanPosition) or ""):lower()
if not validtags[tagName] then
return nil
end
local nextOpener = string.find(text, "<", scanPosition+1) or -1
local nextCloser = string.find(text, ">", scanPosition+1) or -1
if nextCloser > -1 and (nextOpener == -1 or nextCloser < nextOpener) then
local startingTag = string.sub(text, scanPosition, nextCloser)
--We have our starting tag (E.g. '<pre style="color:red">')
--Now find our ending...
if endswith(startingTag, "/>") then --self-closing tag (we are our own ending)
return {
Tag = tagName,
Start = startingTag,
Content = "", End = "",
Length = #startingTag
}
else
local endingTagStart, endingTagEnd = string.find(text, "</"..allcases(tagName).."[ \t\n]*>", scanPosition)
if endingTagStart then --Regular tag formation
local endingTag = string.sub(text, endingTagStart, endingTagEnd)
local tagContent = string.sub(text, nextCloser+1, endingTagStart-1)
return {
Tag = tagName,
Start = startingTag,
Content = tagContent,
End = endingTag,
Length = #startingTag + #tagContent + #endingTag
}
else --Content inside still needs escaping (also linter error!)
return {
Tag = tagName,
Start = startingTag,
Content = "", End = "",
Length = #startingTag
}
end
end
end
return nil
end
local function TestForComment(text, scanPosition) --Like TestForNowikiTag but for <!-- -->
if string.match(text, "^<!%-%-", scanPosition) then
local commentEnd = string.find(text, "-->", scanPosition+4, true)
if commentEnd then
return {
Start = "<!--", End = "-->",
Content = string.sub(text, scanPosition+4, commentEnd-1),
Length = commentEnd-scanPosition+3
}
else --Consumes all text if not given an ending
return {
Start = "<!--", End = "",
Content = string.sub(text, scanPosition+4),
Length = #text-scanPosition+1
}
end
end
return nil
end
--[[ Implementation notes
The goal of this function is to escape all text that wouldn't be parsed if it
was preprocessed (see above implementation notes).
Using keepComments will keep all HTML comments instead of removing them. They
will still be escaped regardless to avoid processing errors
--]]
local function PrepareText(text, keepComments)
local newtext = {}
local scanPosition = 1
while true do
local NextCheck = string.find(text, "<[NnSsPpMm!]", scanPosition) --Advance to the next potential tag we care about
if not NextCheck then --Done
newtext[#newtext+1] = string.sub(text,scanPosition)
break
end
newtext[#newtext+1] = string.sub(text,scanPosition,NextCheck-1)
scanPosition = NextCheck
local Comment = TestForComment(text, scanPosition)
if Comment then
if keepComments then
newtext[#newtext+1] = Comment.Start .. mw.text.nowiki(Comment.Content) .. Comment.End
end
scanPosition = scanPosition + Comment.Length
else
local Tag = TestForNowikiTag(text, scanPosition)
if Tag then
local newTagStart = "<" .. mw.text.nowiki(string.sub(Tag.Start,2,-2)) .. ">"
local newTagEnd =
Tag.End == "" and "" or --Respect no tag ending
"</" .. mw.text.nowiki(string.sub(Tag.End,3,-2)) .. ">"
local newContent = mw.text.nowiki(Tag.Content)
newtext[#newtext+1] = newTagStart .. newContent .. newTagEnd
scanPosition = scanPosition + Tag.Length
else --Nothing special, move on...
newtext[#newtext+1] = string.sub(text, scanPosition, scanPosition)
scanPosition = scanPosition + 1
end
end
end
return table.concat(newtext, "")
end
--[=[ Implementation notes
This function is an alternative to Transcluder's getParameters which considers
the potential for a singular { or } or other odd syntax that %b doesn't like to
be in a parameter's value.
When handling the difference between {{ and {{{, mediawiki will attempt to match
as many sequences of {{{ as possible before matching a {{
E.g.
{{{{A}}}} -> { {{{A}}} }
{{{{{{{{Text|A}}}}}}}} -> {{ {{{ {{{Text|A}}} }}} }}
If there aren't enough triple braces on both sides, the parser will compromise
for a template interpretation.
E.g.
{{{{A}} }} -> {{ {{ A }} }}
While there are technically concerns about things such as wikilinks breaking
template processing (E.g. {{[[}}]]}} doesn't stop at the first }}), it shouldn't
be our job to process inputs perfectly when the input has garbage ({ / } isn't
legal in titles anyways, so if something's unmatched in a wikilink, it's
guaranteed GIGO)
Setting dontEscape will prevent running the input text through EET. Avoid
setting this to true if you don't have to set it.
Returned values:
A table of all templates. Template data goes as follows:
Text: The raw text of the template
Name: The name of the template
Args: A list of arguments
Children: A list of immediate template children
--]=]
--Helper functions
local function boundlen(pair)
return pair.End-pair.Start+1
end
--Main function
local function ParseTemplates(InputText, dontEscape)
--Setup
if not dontEscape then
InputText = PrepareText(InputText)
end
local function finalise(text)
if not dontEscape then
return mw.text.decode(text)
else
return text
end
end
local function CreateContainerObj(Container)
Container.Text = {}
Container.Args = {}
Container.ArgOrder = {}
Container.Children = {}
-- Container.Name = nil
-- Container.Value = nil
-- Container.Key = nil
Container.BeyondStart = false
Container.LastIndex = 1
Container.finalise = finalise
function Container:HandleArgInput(character, internalcall)
if not internalcall then
self.Text[#self.Text+1] = character
end
if character == "=" then
if self.Key then
self.Value[#self.Value+1] = character
else
self.Key = cheaptrim(self.Value and table.concat(self.Value, "") or "")
self.Value = {}
end
else --"|" or "}"
if not self.Name then
self.Name = cheaptrim(self.Value and table.concat(self.Value, "") or "")
self.Value = nil
else
self.Value = self.finalise(self.Value and table.concat(self.Value, "") or "")
if self.Key then
self.Key = self.finalise(self.Key)
self.Args[self.Key] = cheaptrim(self.Value)
self.ArgOrder[#self.ArgOrder+1] = self.Key
else
local Key = tostring(self.LastIndex)
self.Args[Key] = self.Value
self.ArgOrder[#self.ArgOrder+1] = Key
self.LastIndex = self.LastIndex + 1
end
self.Key = nil
self.Value = nil
end
end
end
function Container:AppendText(text, ftext)
self.Text[#self.Text+1] = (ftext or text)
if not self.Value then
self.Value = {}
end
self.BeyondStart = self.BeyondStart or (#table.concat(self.Text, "") > 2)
if self.BeyondStart then
self.Value[#self.Value+1] = text
end
end
function Container:Clean(IsTemplate)
self.Text = table.concat(self.Text, "")
if self.Value and IsTemplate then
self.Value = {string.sub(table.concat(self.Value, ""), 1, -3)} --Trim ending }}
self:HandleArgInput("|", true) --Simulate ending
end
self.Value = nil
self.Key = nil
self.BeyondStart = nil
self.LastIndex = nil
self.finalise = nil
self.HandleArgInput = nil
self.AppendText = nil
self.Clean = nil
end
return Container
end
--Step 1: Find and escape the content of all wikilinks on the page, which are stronger than templates (see implementation notes)
local scannerPosition = 1
local wikilinks = {}
local openWikilinks = {}
while true do
local Position, _, Character = string.find(InputText, "([%[%]])%1", scannerPosition)
if not Position then --Done
break
end
scannerPosition = Position+2 --+2 to pass the [[ / ]]
if Character == "[" then --Add a [[ to the pending wikilink queue
openWikilinks[#openWikilinks+1] = Position
else --Pair up the ]] to any available [[
if #openWikilinks >= 1 then
local start = table.remove(openWikilinks) --Pop the latest [[
wikilinks[start] = {Start=start, End=Position+1, Type="Wikilink"} --Note the pair
end
end
end
--Step 2: Find the bounds of every valid template and variable ({{ and {{{)
local scannerPosition = 1
local templates = {}
local variables = {}
local openBrackets = {}
while true do
local Start, _, Character = string.find(InputText, "([{}])%1", scannerPosition)
if not Start then --Done (both 9e9)
break
end
local _, End = string.find(InputText, "^"..Character.."+", Start)
scannerPosition = Start --Get to the {{ / }} set
if Character == "{" then --Add the {{+ set to the queue
openBrackets[#openBrackets+1] = {Start=Start, End=End}
else --Pair up the }} to any available {{, accounting for {{{ / }}}
local BracketCount = End-Start+1
while BracketCount >= 2 and #openBrackets >= 1 do
local OpenSet = table.remove(openBrackets)
if boundlen(OpenSet) >= 3 and BracketCount >= 3 then --We have a {{{variable}}} (both sides have 3 spare)
variables[OpenSet.End-2] = {Start=OpenSet.End-2, End=scannerPosition+2, Type="Variable"} --Done like this to ensure chronological order
BracketCount = BracketCount - 3
OpenSet.End = OpenSet.End - 3
scannerPosition = scannerPosition + 3
else --We have a {{template}} (both sides have 2 spare, but at least one side doesn't have 3 spare)
templates[OpenSet.End-1] = {Start=OpenSet.End-1, End=scannerPosition+1, Type="Template"} --Done like this to ensure chronological order
BracketCount = BracketCount - 2
OpenSet.End = OpenSet.End - 2
scannerPosition = scannerPosition + 2
end
if boundlen(OpenSet) >= 2 then --Still has enough data left, leave it in
openBrackets[#openBrackets+1] = OpenSet
end
end
end
scannerPosition = End --Now move past the bracket set
end
--Step 3: Re-trace every object using their known bounds, collecting our parameters with (slight) ease
local scannerPosition = 1
local activeObjects = {}
local finalObjects = {}
while true do
local LatestObject = activeObjects[#activeObjects] --Commonly needed object
local NNC, _, Character --NNC = NextNotableCharacter
if LatestObject then
NNC, _, Character = string.find(InputText, "([{}%[%]|=])", scannerPosition)
else
NNC, _, Character = string.find(InputText, "([{}])", scannerPosition) --We are only after templates right now
end
if not NNC then
break
end
if NNC > scannerPosition and LatestObject then
local scannedContent = string.sub(InputText, scannerPosition, NNC-1)
LatestObject:AppendText(scannedContent, finalise(scannedContent))
end
scannerPosition = NNC+1
if Character == "{" or Character == "[" then
local Container = templates[NNC] or variables[NNC] or wikilinks[NNC]
if Container then
CreateContainerObj(Container)
if Container.Type == "Template" then
Container:AppendText("{{")
scannerPosition = NNC+2
elseif Container.Type == "Variable" then
Container:AppendText("{{{")
scannerPosition = NNC+3
else --Wikilink
Container:AppendText("[[")
scannerPosition = NNC+2
end
if LatestObject and Container.Type == "Template" then --Only templates count as children
LatestObject.Children[#LatestObject.Children+1] = Container
end
activeObjects[#activeObjects+1] = Container
elseif LatestObject then
LatestObject:AppendText(Character)
end
elseif Character == "}" or Character == "]" then
if LatestObject then
LatestObject:AppendText(Character)
if LatestObject.End == NNC then
if LatestObject.Type == "Template" then
LatestObject:Clean(true)
finalObjects[#finalObjects+1] = LatestObject
else
LatestObject:Clean(false)
end
activeObjects[#activeObjects] = nil
local NewLatest = activeObjects[#activeObjects]
if NewLatest then
NewLatest:AppendText(LatestObject.Text) --Append to new latest
end
end
end
else --| or =
if LatestObject then
LatestObject:HandleArgInput(Character)
end
end
end
--Step 4: Fix the order
local FixedOrder = {}
local SortableReference = {}
for _,Object in next,finalObjects do
SortableReference[#SortableReference+1] = Object.Start
end
table.sort(SortableReference)
for i = 1,#SortableReference do
local start = SortableReference[i]
for n,Object in next,finalObjects do
if Object.Start == start then
finalObjects[n] = nil
Object.Start = nil --Final cleanup
Object.End = nil
Object.Type = nil
FixedOrder[#FixedOrder+1] = Object
break
end
end
end
--Finished, return
return FixedOrder
end
local p = {}
--Main entry points
p.PrepareText = PrepareText
p.ParseTemplates = ParseTemplates
--Extra entry points, not really required
p.TestForNowikiTag = TestForNowikiTag
p.TestForComment = TestForComment
return p
--[==[ console tests
local s = [=[Hey!{{Text|<nowiki | ||>
Hey! }}
A</nowiki>|<!--AAAAA|AAA-->Should see|Shouldn't see}}]=]
local out = p.PrepareText(s)
mw.logObject(out)
local s = [=[B<!--
Hey!
-->A]=]
local out = p.TestForComment(s, 2)
mw.logObject(out); mw.log(string.sub(s, 2, out.Length))
local a = p.ParseTemplates([=[
{{User:Aidan9382/templates/dummy
|A|B|C {{{A|B}}} { } } {
|<nowiki>D</nowiki>
|<pre>E
|F</pre>
|G|=|a=|A = [[{{PAGENAME}}|A=B]]{{Text|1==<nowiki>}}</nowiki>}}|A B=Success}}
]=])
mw.logObject(a)
]==]