Re: Lua and XML
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- Subject: Re: Lua and XML
- From: Roberto Ierusalimschy <roberto@...>
- Date: 1999年6月21日 13:43:40 -0300
> Have anyone made a XML <-> Lua exporter/importer ?
Well, I wrote a quite dirty "XML importer" in Lua. It reads an XML file
and puts its structure in a table. It is very very simple, and handles
only the tag part of XML (no DTDs, no entities, no declarations, no etc.).
A string such as
<section link="hi">
<title>Hello</title>
This is only a text <ldots/> and more text
</section>
will result in a tree like
{ label = "section",
args = {link="hi"},
n = 3;
{ label = "title", n=1, args={}; "Hello"},
"This is only a text ",
{ label = "ldots", n=0, args={}},
" and more text"
}
-- Roberto
=======================================================================
stack = {n=0}
-- auxiliar function to parse tag attributes
function trataargs (s)
local arg = {}
gsub(s, "(%w+)=([\"'])(.-)%2", function (w, _, a)
%arg[w] = a
end)
return arg
end
-- string "s" is a string with XML marks. This function parses the string
-- and puts the resulting tree in stack[1].
-- (needs Lua 3.2 [beta])
function collect (s)
local top = {n=0}
tinsert(stack, top)
local i = 1
local ni,j,c,label,args, empty = strfind(s, "<(%/?)(%w+)(.-)(%/?)>")
while ni do
local text = strsub(s, i, ni-1)
if not strfind(text, "^%s*$") then
tinsert(top, text)
end
if empty == "/" then -- empty element tag
tinsert(top, {n=0, label=label, args=trataargs(args), empty=1})
elseif c == "" then -- start tag
top = {n=0, label=label, args=trataargs(args)}
tinsert(stack, top) -- new level
else -- end tag
local toclose = tremove(stack) -- remove top
top = stack[stack.n]
if toclose.label ~= label then
error("trying to close "..toclose.label.." with "..label)
end
tinsert(top, toclose)
end
i = j+1
ni,j,c,label,args, empty = strfind(s, "<(%/?)(%w+)(.-)(%/?)>", j)
end
local text = strsub(s, i)
if not strfind(text, "^%s*$") then
tinsert(stack[stack.n], text)
end
end