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-rw-r--r--util/template.lua112
1 files changed, 112 insertions, 0 deletions
diff --git a/util/template.lua b/util/template.lua
new file mode 100644
index 00000000..c143a216
--- /dev/null
+++ b/util/template.lua
@@ -0,0 +1,112 @@
+
+local t_insert = table.insert;
+local st = require "util.stanza";
+local lxp = require "lxp";
+local setmetatable = setmetatable;
+local pairs = pairs;
+local error = error;
+local s_gsub = string.gsub;
+
+local print = print;
+
+module("template")
+
+local function process_stanza(stanza, ops)
+ -- process attrs
+ for key, val in pairs(stanza.attr) do
+ if val:match("{[^}]*}") then
+ t_insert(ops, {stanza.attr, key, val});
+ end
+ end
+ -- process children
+ local i = 1;
+ while i <= #stanza do
+ local child = stanza[i];
+ if child.name then
+ process_stanza(child, ops);
+ elseif child:match("{[^}]*}") then -- text
+ t_insert(ops, {stanza, i, child});
+ end
+ i = i + 1;
+ end
+end
+
+local parse_xml = (function()
+ local ns_prefixes = {
+ ["http://www.w3.org/XML/1998/namespace"] = "xml";
+ };
+ local ns_separator = "\1";
+ local ns_pattern = "^([^"..ns_separator.."]*)"..ns_separator.."?(.*)$";
+ return function(xml)
+ local handler = {};
+ local stanza = st.stanza("root");
+ function handler:StartElement(tagname, attr)
+ local curr_ns,name = tagname:match(ns_pattern);
+ if name == "" then
+ curr_ns, name = "", curr_ns;
+ end
+ if curr_ns ~= "" then
+ attr.xmlns = curr_ns;
+ end
+ for i=1,#attr do
+ local k = attr[i];
+ attr[i] = nil;
+ local ns, nm = k:match(ns_pattern);
+ if nm ~= "" then
+ ns = ns_prefixes[ns];
+ if ns then
+ attr[ns..":"..nm] = attr[k];
+ attr[k] = nil;
+ end
+ end
+ end
+ stanza:tag(name, attr);
+ end
+ function handler:CharacterData(data)
+ data = data:gsub("^%s*", ""):gsub("%s*$", "");
+ stanza:text(data);
+ end
+ function handler:EndElement(tagname)
+ stanza:up();
+ end
+ local parser = lxp.new(handler, "\1");
+ local ok, err, line, col = parser:parse(xml);
+ if ok then ok, err, line, col = parser:parse(); end
+ --parser:close();
+ if ok then
+ return stanza.tags[1];
+ else
+ return ok, err.." (line "..line..", col "..col..")";
+ end
+ end;
+end)();
+
+local function create_template(text)
+ local stanza, err = parse_xml(text);
+ if not stanza then error(err); end
+ local ops = {};
+ process_stanza(stanza, ops);
+ ops.stanza = stanza;
+
+ local template = {};
+ function template.apply(data)
+ local newops = st.clone(ops);
+ for i=1,#newops do
+ local op = newops[i];
+ local t, k, v = op[1], op[2], op[3];
+ t[k] = s_gsub(v, "{([^}]*)}", data);
+ end
+ return newops.stanza;
+ end
+ return template;
+end
+
+local templates = setmetatable({}, { __mode = 'k' });
+return function(text)
+ local template = templates[text];
+ if not template then
+ template = create_template(text);
+ templates[text] = template;
+ end
+ return template;
+end;