782 lines
25 KiB
Lua
782 lines
25 KiB
Lua
--- XML LOM Utilities.
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--
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-- This implements some useful things on [LOM](http://matthewwild.co.uk/projects/luaexpat/lom.html) documents, such as returned by `lxp.lom.parse`.
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-- In particular, it can convert LOM back into XML text, with optional pretty-printing control.
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-- It is s based on stanza.lua from [Prosody](http://hg.prosody.im/trunk/file/4621c92d2368/util/stanza.lua)
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--
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-- > d = xml.parse "<nodes><node id='1'>alice</node></nodes>"
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-- > = d
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-- <nodes><node id='1'>alice</node></nodes>
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-- > = xml.tostring(d,'',' ')
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-- <nodes>
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-- <node id='1'>alice</node>
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-- </nodes>
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--
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-- Can be used as a lightweight one-stop-shop for simple XML processing; a simple XML parser is included
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-- but the default is to use `lxp.lom` if it can be found.
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-- <pre>
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-- Prosody IM
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-- Copyright (C) 2008-2010 Matthew Wild
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-- Copyright (C) 2008-2010 Waqas Hussain--
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-- classic Lua XML parser by Roberto Ierusalimschy.
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-- modified to output LOM format.
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-- http://lua-users.org/wiki/LuaXml
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-- </pre>
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-- See @{06-data.md.XML|the Guide}
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--
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-- Dependencies: `pl.utils`
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--
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-- Soft Dependencies: `lxp.lom` (fallback is to use basic Lua parser)
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-- @module pl.xml
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local utils = require 'pl.utils'
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local split = utils.split;
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local t_insert = table.insert;
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local t_concat = table.concat;
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local t_remove = table.remove;
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local s_format = string.format;
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local s_match = string.match;
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local tostring = tostring;
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local setmetatable = setmetatable;
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local getmetatable = getmetatable;
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local pairs = pairs;
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local ipairs = ipairs;
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local type = type;
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local next = next;
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local print = print;
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local unpack = utils.unpack;
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local s_gsub = string.gsub;
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local s_char = string.char;
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local s_find = string.find;
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local os = os;
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local pcall,require,io = pcall,require,io
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local _M = {}
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local Doc = { __type = "doc" };
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Doc.__index = Doc;
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--- create a new document node.
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-- @param tag the tag name
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-- @param attr optional attributes (table of name-value pairs)
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function _M.new(tag, attr)
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local doc = { tag = tag, attr = attr or {}, last_add = {}};
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return setmetatable(doc, Doc);
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end
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--- parse an XML document. By default, this uses lxp.lom.parse, but
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-- falls back to basic_parse, or if use_basic is true
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-- @param text_or_file file or string representation
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-- @param is_file whether text_or_file is a file name or not
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-- @param use_basic do a basic parse
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-- @return a parsed LOM document with the document metatatables set
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-- @return nil, error the error can either be a file error or a parse error
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function _M.parse(text_or_file, is_file, use_basic)
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local parser,status,lom
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if use_basic then parser = _M.basic_parse
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else
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status,lom = pcall(require,'lxp.lom')
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if not status then parser = _M.basic_parse else parser = lom.parse end
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end
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if is_file then
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local f,err = io.open(text_or_file)
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if not f then return nil,err end
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text_or_file = f:read '*a'
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f:close()
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end
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local doc,err = parser(text_or_file)
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if not doc then return nil,err end
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if lom then
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_M.walk(doc,false,function(_,d)
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setmetatable(d,Doc)
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end)
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end
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return doc
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end
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---- convenient function to add a document node, This updates the last inserted position.
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-- @param tag a tag name
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-- @param attrs optional set of attributes (name-string pairs)
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function Doc:addtag(tag, attrs)
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local s = _M.new(tag, attrs);
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(self.last_add[#self.last_add] or self):add_direct_child(s);
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t_insert(self.last_add, s);
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return self;
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end
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--- convenient function to add a text node. This updates the last inserted position.
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-- @param text a string
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function Doc:text(text)
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(self.last_add[#self.last_add] or self):add_direct_child(text);
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return self;
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end
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---- go up one level in a document
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function Doc:up()
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t_remove(self.last_add);
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return self;
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end
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function Doc:reset()
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local last_add = self.last_add;
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for i = 1,#last_add do
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last_add[i] = nil;
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end
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return self;
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end
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--- append a child to a document directly.
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-- @param child a child node (either text or a document)
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function Doc:add_direct_child(child)
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t_insert(self, child);
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end
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--- append a child to a document at the last element added
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-- @param child a child node (either text or a document)
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function Doc:add_child(child)
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(self.last_add[#self.last_add] or self):add_direct_child(child);
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return self;
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end
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--accessing attributes: useful not to have to expose implementation (attr)
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--but also can allow attr to be nil in any future optimizations
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--- set attributes of a document node.
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-- @param t a table containing attribute/value pairs
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function Doc:set_attribs (t)
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for k,v in pairs(t) do
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self.attr[k] = v
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end
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end
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--- set a single attribute of a document node.
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-- @param a attribute
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-- @param v its value
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function Doc:set_attrib(a,v)
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self.attr[a] = v
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end
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--- access the attributes of a document node.
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function Doc:get_attribs()
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return self.attr
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end
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local function is_text(s) return type(s) == 'string' end
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--- function to create an element with a given tag name and a set of children.
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-- @param tag a tag name
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-- @param items either text or a table where the hash part is the attributes and the list part is the children.
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function _M.elem(tag,items)
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local s = _M.new(tag)
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if is_text(items) then items = {items} end
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if _M.is_tag(items) then
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t_insert(s,items)
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elseif type(items) == 'table' then
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for k,v in pairs(items) do
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if is_text(k) then
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s.attr[k] = v
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t_insert(s.attr,k)
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else
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s[k] = v
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end
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end
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end
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return s
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end
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--- given a list of names, return a number of element constructors.
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-- @param list a list of names, or a comma-separated string.
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-- @usage local parent,children = doc.tags 'parent,children' <br>
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-- doc = parent {child 'one', child 'two'}
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function _M.tags(list)
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local ctors = {}
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local elem = _M.elem
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if is_text(list) then list = split(list,'%s*,%s*') end
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for _,tag in ipairs(list) do
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local ctor = function(items) return _M.elem(tag,items) end
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t_insert(ctors,ctor)
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end
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return unpack(ctors)
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end
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local templ_cache = {}
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local function template_cache (templ)
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if is_text(templ) then
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if templ_cache[templ] then
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templ = templ_cache[templ]
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else
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local str,err = templ
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templ,err = _M.parse(str,false,true)
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if not templ then return nil,err end
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templ_cache[str] = templ
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end
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elseif not _M.is_tag(templ) then
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return nil, "template is not a document"
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end
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return templ
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end
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local function is_data(data)
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return #data == 0 or type(data[1]) ~= 'table'
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end
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local function prepare_data(data)
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-- a hack for ensuring that $1 maps to first element of data, etc.
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-- Either this or could change the gsub call just below.
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for i,v in ipairs(data) do
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data[tostring(i)] = v
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end
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end
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--- create a substituted copy of a document,
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-- @param templ may be a document or a string representation which will be parsed and cached
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-- @param data a table of name-value pairs or a list of such tables
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-- @return an XML document
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function Doc.subst(templ, data)
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local err
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if type(data) ~= 'table' or not next(data) then return nil, "data must be a non-empty table" end
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if is_data(data) then
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prepare_data(data)
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end
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templ,err = template_cache(templ)
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if err then return nil, err end
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local function _subst(item)
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return _M.clone(templ,function(s)
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return s:gsub('%$(%w+)',item)
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end)
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end
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if is_data(data) then return _subst(data) end
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local list = {}
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for _,item in ipairs(data) do
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prepare_data(item)
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t_insert(list,_subst(item))
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end
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if data.tag then
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list = _M.elem(data.tag,list)
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end
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return list
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end
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--- get the first child with a given tag name.
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-- @param tag the tag name
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function Doc:child_with_name(tag)
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for _, child in ipairs(self) do
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if child.tag == tag then return child; end
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end
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end
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local _children_with_name
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function _children_with_name(self,tag,list,recurse)
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for _, child in ipairs(self) do if type(child) == 'table' then
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if child.tag == tag then t_insert(list,child) end
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if recurse then _children_with_name(child,tag,list,recurse) end
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end end
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end
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--- get all elements in a document that have a given tag.
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-- @param tag a tag name
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-- @param dont_recurse optionally only return the immediate children with this tag name
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-- @return a list of elements
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function Doc:get_elements_with_name(tag,dont_recurse)
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local res = {}
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_children_with_name(self,tag,res,not dont_recurse)
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return res
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end
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-- iterate over all children of a document node, including text nodes.
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function Doc:children()
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local i = 0;
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return function (a)
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i = i + 1
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return a[i];
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end, self, i;
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end
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-- return the first child element of a node, if it exists.
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function Doc:first_childtag()
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if #self == 0 then return end
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for _,t in ipairs(self) do
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if type(t) == 'table' then return t end
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end
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end
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function Doc:matching_tags(tag, xmlns)
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xmlns = xmlns or self.attr.xmlns;
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local tags = self;
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local start_i, max_i, v = 1, #tags;
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return function ()
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for i=start_i,max_i do
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v = tags[i];
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if (not tag or v.tag == tag)
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and (not xmlns or xmlns == v.attr.xmlns) then
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start_i = i+1;
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return v;
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end
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end
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end, tags, start_i;
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end
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--- iterate over all child elements of a document node.
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function Doc:childtags()
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local i = 0;
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return function (a)
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local v
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repeat
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i = i + 1
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v = self[i]
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if v and type(v) == 'table' then return v; end
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until not v
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end, self[1], i;
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end
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--- visit child element of a node and call a function, possibility modifying the document.
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-- @param callback a function passed the node (text or element). If it returns nil, that node will be removed.
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-- If it returns a value, that will replace the current node.
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function Doc:maptags(callback)
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local is_tag = _M.is_tag
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local i = 1;
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while i <= #self do
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if is_tag(self[i]) then
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local ret = callback(self[i]);
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if ret == nil then
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t_remove(self, i);
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else
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self[i] = ret;
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i = i + 1;
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end
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end
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end
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return self;
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end
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local xml_escape
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do
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local escape_table = { ["'"] = "'", ["\""] = """, ["<"] = "<", [">"] = ">", ["&"] = "&" };
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function xml_escape(str) return (s_gsub(str, "['&<>\"]", escape_table)); end
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_M.xml_escape = xml_escape;
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end
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-- pretty printing
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-- if indent, then put each new tag on its own line
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-- if attr_indent, put each new attribute on its own line
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local function _dostring(t, buf, self, xml_escape, parentns, idn, indent, attr_indent)
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local nsid = 0;
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local tag = t.tag
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local lf,alf = ""," "
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if indent then lf = '\n'..idn end
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if attr_indent then alf = '\n'..idn..attr_indent end
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t_insert(buf, lf.."<"..tag);
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local function write_attr(k,v)
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if s_find(k, "\1", 1, true) then
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local ns, attrk = s_match(k, "^([^\1]*)\1?(.*)$");
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nsid = nsid + 1;
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t_insert(buf, " xmlns:ns"..nsid.."='"..xml_escape(ns).."' ".."ns"..nsid..":"..attrk.."='"..xml_escape(v).."'");
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elseif not(k == "xmlns" and v == parentns) then
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t_insert(buf, alf..k.."='"..xml_escape(v).."'");
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end
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end
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-- it's useful for testing to have predictable attribute ordering, if available
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if #t.attr > 0 then
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for _,k in ipairs(t.attr) do
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write_attr(k,t.attr[k])
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end
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else
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for k, v in pairs(t.attr) do
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write_attr(k,v)
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end
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end
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local len,has_children = #t;
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if len == 0 then
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local out = "/>"
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if attr_indent then out = '\n'..idn..out end
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t_insert(buf, out);
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else
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t_insert(buf, ">");
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for n=1,len do
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local child = t[n];
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if child.tag then
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self(child, buf, self, xml_escape, t.attr.xmlns,idn and idn..indent, indent, attr_indent );
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has_children = true
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else -- text element
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t_insert(buf, xml_escape(child));
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end
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end
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t_insert(buf, (has_children and lf or '').."</"..tag..">");
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end
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end
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---- pretty-print an XML document
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--- @param t an XML document
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--- @param idn an initial indent (indents are all strings)
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--- @param indent an indent for each level
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--- @param attr_indent if given, indent each attribute pair and put on a separate line
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--- @param xml force prefacing with default or custom <?xml...>
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--- @return a string representation
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function _M.tostring(t,idn,indent, attr_indent, xml)
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local buf = {};
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if xml then
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if type(xml) == "string" then
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buf[1] = xml
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else
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buf[1] = "<?xml version='1.0'?>"
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end
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end
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_dostring(t, buf, _dostring, xml_escape, nil,idn,indent, attr_indent);
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return t_concat(buf);
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end
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Doc.__tostring = _M.tostring
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--- get the full text value of an element
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function Doc:get_text()
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local res = {}
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for i,el in ipairs(self) do
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if is_text(el) then t_insert(res,el) end
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end
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return t_concat(res);
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end
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--- make a copy of a document
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-- @param doc the original document
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-- @param strsubst an optional function for handling string copying which could do substitution, etc.
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function _M.clone(doc, strsubst)
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local lookup_table = {};
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local function _copy(object,kind,parent)
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if type(object) ~= "table" then
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if strsubst and is_text(object) then return strsubst(object,kind,parent)
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else return object
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end
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elseif lookup_table[object] then
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return lookup_table[object]
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end
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local new_table = {};
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lookup_table[object] = new_table
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local tag = object.tag
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new_table.tag = _copy(tag,'*TAG',parent)
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if object.attr then
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local res = {}
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for attr,value in pairs(object.attr) do
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res[attr] = _copy(value,attr,object)
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end
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new_table.attr = res
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end
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for index = 1,#object do
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local v = _copy(object[index],'*TEXT',object)
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t_insert(new_table,v)
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end
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return setmetatable(new_table, getmetatable(object))
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end
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return _copy(doc)
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end
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Doc.filter = _M.clone -- also available as method
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--- compare two documents.
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-- @param t1 any value
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-- @param t2 any value
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function _M.compare(t1,t2)
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local ty1 = type(t1)
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local ty2 = type(t2)
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if ty1 ~= ty2 then return false, 'type mismatch' end
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if ty1 == 'string' then
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return t1 == t2 and true or 'text '..t1..' ~= text '..t2
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end
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if ty1 ~= 'table' or ty2 ~= 'table' then return false, 'not a document' end
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if t1.tag ~= t2.tag then return false, 'tag '..t1.tag..' ~= tag '..t2.tag end
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if #t1 ~= #t2 then return false, 'size '..#t1..' ~= size '..#t2..' for tag '..t1.tag end
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-- compare attributes
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for k,v in pairs(t1.attr) do
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if t2.attr[k] ~= v then return false, 'mismatch attrib' end
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end
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for k,v in pairs(t2.attr) do
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if t1.attr[k] ~= v then return false, 'mismatch attrib' end
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end
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-- compare children
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for i = 1,#t1 do
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local yes,err = _M.compare(t1[i],t2[i])
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if not yes then return err end
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end
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return true
|
|
end
|
|
|
|
--- is this value a document element?
|
|
-- @param d any value
|
|
function _M.is_tag(d)
|
|
return type(d) == 'table' and is_text(d.tag)
|
|
end
|
|
|
|
--- call the desired function recursively over the document.
|
|
-- @param doc the document
|
|
-- @param depth_first visit child notes first, then the current node
|
|
-- @param operation a function which will receive the current tag name and current node.
|
|
function _M.walk (doc, depth_first, operation)
|
|
if not depth_first then operation(doc.tag,doc) end
|
|
for _,d in ipairs(doc) do
|
|
if _M.is_tag(d) then
|
|
_M.walk(d,depth_first,operation)
|
|
end
|
|
end
|
|
if depth_first then operation(doc.tag,doc) end
|
|
end
|
|
|
|
local html_empty_elements = { --lists all HTML empty (void) elements
|
|
br = true,
|
|
img = true,
|
|
meta = true,
|
|
frame = true,
|
|
area = true,
|
|
hr = true,
|
|
base = true,
|
|
col = true,
|
|
link = true,
|
|
input = true,
|
|
option = true,
|
|
param = true,
|
|
isindex = true,
|
|
embed = true,
|
|
}
|
|
|
|
local escapes = { quot = "\"", apos = "'", lt = "<", gt = ">", amp = "&" }
|
|
local function unescape(str) return (str:gsub( "&(%a+);", escapes)); end
|
|
|
|
--- Parse a well-formed HTML file as a string.
|
|
-- Tags are case-insenstive, DOCTYPE is ignored, and empty elements can be .. empty.
|
|
-- @param s the HTML
|
|
function _M.parsehtml (s)
|
|
return _M.basic_parse(s,false,true)
|
|
end
|
|
|
|
--- Parse a simple XML document using a pure Lua parser based on Robero Ierusalimschy's original version.
|
|
-- @param s the XML document to be parsed.
|
|
-- @param all_text if true, preserves all whitespace. Otherwise only text containing non-whitespace is included.
|
|
-- @param html if true, uses relaxed HTML rules for parsing
|
|
function _M.basic_parse(s,all_text,html)
|
|
local t_insert,t_remove = table.insert,table.remove
|
|
local s_find,s_sub = string.find,string.sub
|
|
local stack = {}
|
|
local top = {}
|
|
|
|
local function parseargs(s)
|
|
local arg = {}
|
|
s:gsub("([%w:%-_]+)%s*=%s*([\"'])(.-)%2", function (w, _, a)
|
|
if html then w = w:lower() end
|
|
arg[w] = unescape(a)
|
|
end)
|
|
if html then
|
|
s:gsub("([%w:%-_]+)%s*=%s*([^\"']+)%s*", function (w, a)
|
|
w = w:lower()
|
|
arg[w] = unescape(a)
|
|
end)
|
|
end
|
|
return arg
|
|
end
|
|
|
|
t_insert(stack, top)
|
|
local ni,c,label,xarg, empty, _, istart
|
|
local i, j = 1, 1
|
|
-- we're not interested in <?xml version="1.0"?>
|
|
_,istart = s_find(s,'^%s*<%?[^%?]+%?>%s*')
|
|
if not istart then -- or <!DOCTYPE ...>
|
|
_,istart = s_find(s,'^%s*<!DOCTYPE.->%s*')
|
|
end
|
|
if istart then i = istart+1 end
|
|
while true do
|
|
ni,j,c,label,xarg, empty = s_find(s, "<([%/!]?)([%w:%-_]+)(.-)(%/?)>", i)
|
|
if not ni then break end
|
|
if c == "!" then -- comment
|
|
-- case where there's no space inside comment
|
|
if not (label:match '%-%-$' and xarg == '') then
|
|
if xarg:match '%-%-$' then -- we've grabbed it all
|
|
j = j - 2
|
|
end
|
|
-- match end of comment
|
|
_,j = s_find(s, "-->", j, true)
|
|
end
|
|
else
|
|
local text = s_sub(s, i, ni-1)
|
|
if html then
|
|
label = label:lower()
|
|
if html_empty_elements[label] then empty = "/" end
|
|
if label == 'script' then
|
|
end
|
|
end
|
|
if all_text or not s_find(text, "^%s*$") then
|
|
t_insert(top, unescape(text))
|
|
end
|
|
if empty == "/" then -- empty element tag
|
|
t_insert(top, setmetatable({tag=label, attr=parseargs(xarg), empty=1},Doc))
|
|
elseif c == "" then -- start tag
|
|
top = setmetatable({tag=label, attr=parseargs(xarg)},Doc)
|
|
t_insert(stack, top) -- new level
|
|
else -- end tag
|
|
local toclose = t_remove(stack) -- remove top
|
|
top = stack[#stack]
|
|
if #stack < 1 then
|
|
error("nothing to close with "..label..':'..text)
|
|
end
|
|
if toclose.tag ~= label then
|
|
error("trying to close "..toclose.tag.." with "..label.." "..text)
|
|
end
|
|
t_insert(top, toclose)
|
|
end
|
|
end
|
|
i = j+1
|
|
end
|
|
local text = s_sub(s, i)
|
|
if all_text or not s_find(text, "^%s*$") then
|
|
t_insert(stack[#stack], unescape(text))
|
|
end
|
|
if #stack > 1 then
|
|
error("unclosed "..stack[#stack].tag)
|
|
end
|
|
local res = stack[1]
|
|
return is_text(res[1]) and res[2] or res[1]
|
|
end
|
|
|
|
local function empty(attr) return not attr or not next(attr) end
|
|
local function is_element(d) return type(d) == 'table' and d.tag ~= nil end
|
|
|
|
-- returns the key,value pair from a table if it has exactly one entry
|
|
local function has_one_element(t)
|
|
local key,value = next(t)
|
|
if next(t,key) ~= nil then return false end
|
|
return key,value
|
|
end
|
|
|
|
local function append_capture(res,tbl)
|
|
if not empty(tbl) then -- no point in capturing empty tables...
|
|
local key
|
|
if tbl._ then -- if $_ was set then it is meant as the top-level key for the captured table
|
|
key = tbl._
|
|
tbl._ = nil
|
|
if empty(tbl) then return end
|
|
end
|
|
-- a table with only one pair {[0]=value} shall be reduced to that value
|
|
local numkey,val = has_one_element(tbl)
|
|
if numkey == 0 then tbl = val end
|
|
if key then
|
|
res[key] = tbl
|
|
else -- otherwise, we append the captured table
|
|
t_insert(res,tbl)
|
|
end
|
|
end
|
|
end
|
|
|
|
local function make_number(pat)
|
|
if pat:find '^%d+$' then -- $1 etc means use this as an array location
|
|
pat = tonumber(pat)
|
|
end
|
|
return pat
|
|
end
|
|
|
|
local function capture_attrib(res,pat,value)
|
|
pat = make_number(pat:sub(2))
|
|
res[pat] = value
|
|
return true
|
|
end
|
|
|
|
local match
|
|
function match(d,pat,res,keep_going)
|
|
local ret = true
|
|
if d == nil then d = '' end --return false end
|
|
-- attribute string matching is straight equality, except if the pattern is a $ capture,
|
|
-- which always succeeds.
|
|
if is_text(d) then
|
|
if not is_text(pat) then return false end
|
|
if _M.debug then print(d,pat) end
|
|
if pat:find '^%$' then
|
|
return capture_attrib(res,pat,d)
|
|
else
|
|
return d == pat
|
|
end
|
|
else
|
|
if _M.debug then print(d.tag,pat.tag) end
|
|
-- this is an element node. For a match to succeed, the attributes must
|
|
-- match as well.
|
|
-- a tagname in the pattern ending with '-' is a wildcard and matches like an attribute
|
|
local tagpat = pat.tag:match '^(.-)%-$'
|
|
if tagpat then
|
|
tagpat = make_number(tagpat)
|
|
res[tagpat] = d.tag
|
|
end
|
|
if d.tag == pat.tag or tagpat then
|
|
|
|
if not empty(pat.attr) then
|
|
if empty(d.attr) then ret = false
|
|
else
|
|
for prop,pval in pairs(pat.attr) do
|
|
local dval = d.attr[prop]
|
|
if not match(dval,pval,res) then ret = false; break end
|
|
end
|
|
end
|
|
end
|
|
-- the pattern may have child nodes. We match partially, so that {P1,P2} shall match {X,P1,X,X,P2,..}
|
|
if ret and #pat > 0 then
|
|
local i,j = 1,1
|
|
local function next_elem()
|
|
j = j + 1 -- next child element of data
|
|
if is_text(d[j]) then j = j + 1 end
|
|
return j <= #d
|
|
end
|
|
repeat
|
|
local p = pat[i]
|
|
-- repeated {{<...>}} patterns shall match one or more elements
|
|
-- so e.g. {P+} will match {X,X,P,P,X,P,X,X,X}
|
|
if is_element(p) and p.repeated then
|
|
local found
|
|
repeat
|
|
local tbl = {}
|
|
ret = match(d[j],p,tbl,false)
|
|
if ret then
|
|
found = false --true
|
|
append_capture(res,tbl)
|
|
end
|
|
until not next_elem() or (found and not ret)
|
|
i = i + 1
|
|
else
|
|
ret = match(d[j],p,res,false)
|
|
if ret then i = i + 1 end
|
|
end
|
|
until not next_elem() or i > #pat -- run out of elements or patterns to match
|
|
-- if every element in our pattern matched ok, then it's been a successful match
|
|
if i > #pat then return true end
|
|
end
|
|
if ret then return true end
|
|
else
|
|
ret = false
|
|
end
|
|
-- keep going anyway - look at the children!
|
|
if keep_going then
|
|
for child in d:childtags() do
|
|
ret = match(child,pat,res,keep_going)
|
|
if ret then break end
|
|
end
|
|
end
|
|
end
|
|
return ret
|
|
end
|
|
|
|
function Doc:match(pat)
|
|
local err
|
|
pat,err = template_cache(pat)
|
|
if not pat then return nil, err end
|
|
_M.walk(pat,false,function(_,d)
|
|
if is_text(d[1]) and is_element(d[2]) and is_text(d[3]) and
|
|
d[1]:find '%s*{{' and d[3]:find '}}%s*' then
|
|
t_remove(d,1)
|
|
t_remove(d,2)
|
|
d[1].repeated = true
|
|
end
|
|
end)
|
|
|
|
local res = {}
|
|
local ret = match(self,pat,res,true)
|
|
return res,ret
|
|
end
|
|
|
|
|
|
return _M
|
|
|