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comparison util/template.lua @ 3545:c85f9a4ae1c4

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util.template: Initial commit. A template library for XML stanzas.
author Waqas Hussain <waqas20@gmail.com>
date Sun, 24 Oct 2010 15:06:13 +0500
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children cb1600dea3ad
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3544:f2aca3e0fe3b 3545:c85f9a4ae1c4
1
2 local t_insert = table.insert;
3 local st = require "util.stanza";
4 local lxp = require "lxp";
5 local setmetatable = setmetatable;
6 local pairs = pairs;
7 local error = error;
8 local s_gsub = string.gsub;
9
10 local print = print;
11
12 module("template")
13
14 local function process_stanza(stanza, ops)
15 -- process attrs
16 for key, val in pairs(stanza.attr) do
17 if val:match("{[^}]*}") then
18 t_insert(ops, {stanza.attr, key, val});
19 end
20 end
21 -- process children
22 local i = 1;
23 while i <= #stanza do
24 local child = stanza[i];
25 if child.name then
26 process_stanza(child, ops);
27 elseif child:match("{[^}]*}") then -- text
28 t_insert(ops, {stanza, i, child});
29 end
30 i = i + 1;
31 end
32 end
33
34 local parse_xml = (function()
35 local ns_prefixes = {
36 ["http://www.w3.org/XML/1998/namespace"] = "xml";
37 };
38 local ns_separator = "\1";
39 local ns_pattern = "^([^"..ns_separator.."]*)"..ns_separator.."?(.*)$";
40 return function(xml)
41 local handler = {};
42 local stanza = st.stanza("root");
43 function handler:StartElement(tagname, attr)
44 local curr_ns,name = tagname:match(ns_pattern);
45 if name == "" then
46 curr_ns, name = "", curr_ns;
47 end
48 if curr_ns ~= "" then
49 attr.xmlns = curr_ns;
50 end
51 for i=1,#attr do
52 local k = attr[i];
53 attr[i] = nil;
54 local ns, nm = k:match(ns_pattern);
55 if nm ~= "" then
56 ns = ns_prefixes[ns];
57 if ns then
58 attr[ns..":"..nm] = attr[k];
59 attr[k] = nil;
60 end
61 end
62 end
63 stanza:tag(name, attr);
64 end
65 function handler:CharacterData(data)
66 data = data:gsub("^%s*", ""):gsub("%s*$", "");
67 stanza:text(data);
68 end
69 function handler:EndElement(tagname)
70 stanza:up();
71 end
72 local parser = lxp.new(handler, "\1");
73 local ok, err, line, col = parser:parse(xml);
74 if ok then ok, err, line, col = parser:parse(); end
75 --parser:close();
76 if ok then
77 return stanza.tags[1];
78 else
79 return ok, err.." (line "..line..", col "..col..")";
80 end
81 end;
82 end)();
83
84 local function create_template(text)
85 local stanza, err = parse_xml(text);
86 if not stanza then error(err); end
87 local ops = {};
88 process_stanza(stanza, ops);
89 ops.stanza = stanza;
90
91 local template = {};
92 function template.apply(data)
93 local newops = st.clone(ops);
94 for i=1,#newops do
95 local op = newops[i];
96 local t, k, v = op[1], op[2], op[3];
97 t[k] = s_gsub(v, "{([^}]*)}", data);
98 end
99 return newops.stanza;
100 end
101 return template;
102 end
103
104 local templates = setmetatable({}, { __mode = 'k' });
105 return function(text)
106 local template = templates[text];
107 if not template then
108 template = create_template(text);
109 templates[text] = template;
110 end
111 return template;
112 end;