Module:Item

 localp={}

 localfunctionescape(str)
 returnstr:gsub("[|\\]",function(c)returnstring.format("\\%03d",c:byte())end)
 end

 localfunctionunescape(str)
 returnstr:gsub("\\(%d%d%d)",function(d)returnstring.char(d)end)
 end

 -- Implements [[Template:Item]]
 functionp.pack(frame)
 localparent=frame:getParent()
 localresult=''
 forkey,valueinpairs(parent.args)do
 result=result.."|"..escape(tostring(key)).."|"..escape(value)
 end
 returnresult.."|";
 end

 localfunctionunpack(str)
 localresult={}
 forkey,valueinstr:gfind("|([^|]*)|([^|]*)")do
 result[unescape(key)]=unescape(value)
 end
 returnresult
 end

 -- Implements [[Template:Component]]
 functionp.component(frame)
 returnunpack(frame.args[1])[frame.args[2]]
 end

 localfunctiongetItems(frame)
 returnframe:getParent().args
 end

 localfunctioninvert(tbl)
 localresult={}
 forkey,valueinpairs(tbl)do
 result[value]=key
 end
 returnresult
 end

 -- Add args into item as appropriate (see [[Template:Format item]])
 localfunctionaddArgs(
 item,-- unpacked item to modify
 args,-- arguments for adding into item
 ignore,-- pass in invert{keys to ignore}
 shift-- for numbered arguments, args[key+shift] is assigned to item[key]
 -- returns: item
 )
 forkey,valueinpairs(args)do
 ifnotignore[key]then
 local_,_,paramKey=string.find(key,"^param (.*)")
 local_,_,importantKey=string.find(key,"^important (.*)")
 paramKey=paramKeyorimportantKeyorkey
 ifshiftandtype(paramKey)=="number"then
 paramKey=paramKey-shift
 ifparamKey<1thenparamKey=nilend
 end
 ifparamKeyand(importantKeyoritem[paramKey]==nil)then
 item[paramKey]=value
 end
 end
 end

 returnitem
 end

 -- Implements [[Template:Format item]]
 functionp.format(frame)
 localargs=frame:getParent().args
 localignore=invert{"template","item"}
 localtemplateArgs=addArgs(unpack(args.item),args,ignore)

 returnframe:expandTemplate{title=args.template,args=templateArgs}
 end

 -- See [[Template:Item#Format each item using a template]]
 functionp.each(frame)
 localargs=frame.args
 localitems=getItems(frame)
 localseparator=args[1]or""
 localprepend=args[2]or""
 localappend=args[3]or""
 localignore=invert{"template"}
 localshift=3

 localresult=""
 fori,iteminipairs(items)do
 localtemplateArgs=addArgs(unpack(item),args,ignore,shift)
 result=result..prepend..frame:expandTemplate{title=args.template,args=templateArgs}..append
 ifitems[i+1]then
 result=result..separator
 end
 end
 returnresult
 end

 -- See [[Template:Item#Gather given parameter from all items]]
 functionp.gather(frame)
 localargs=frame.args
 localitems=getItems(frame)
 localparameter=args.parameteror"1"

 localtemplateArgs={}
 fori,iteminipairs(items)do
 templateArgs[i]=unpack(item)[parameter]
 end

 returnframe:expandTemplate{title=args.template,args=templateArgs}
 end

 returnp