File

util/xtemplate.lua @ 12590:5eaf77114fdb

compat: Use table.pack (there since Lua 5.2) over our util.table Added in d278a770eddc avoid having to deal with its absence in Lua 5.1. No longer needed when Lua 5.1 support is dropped.
author Kim Alvefur <zash@zash.se>
date Mon, 11 Jul 2022 19:15:24 +0200
parent 12213:dc9d63166488
child 12975:d10957394a3c
line wrap: on
line source

local s_gsub = string.gsub;
local s_match = string.match;
local s_sub = string.sub;
local t_concat = table.concat;

local st = require("util.stanza");

local function render(template, root, escape, filters)
	escape = escape or st.xml_escape;

	return (s_gsub(template, "%b{}", function(block)
		local inner = s_sub(block, 2, -2);
		local path, pipe, pos = s_match(inner, "^([^|]+)(|?)()");
		if not (type(path) == "string") then return end
		local value
		if path == "." then
			value = root;
		elseif path == "#" then
			value = root:get_text();
		else
			value = root:find(path);
		end
		local is_escaped = false;

		while pipe == "|" do
			local func, args, tmpl, p = s_match(inner, "^(%w+)(%b())(%b{})()", pos);
			if not func then func, args, p = s_match(inner, "^(%w+)(%b())()", pos); end
			if not func then func, tmpl, p = s_match(inner, "^(%w+)(%b{})()", pos); end
			if not func then func, p = s_match(inner, "^(%w+)()", pos); end
			if not func then break end
			if tmpl then tmpl = s_sub(tmpl, 2, -2); end
			if args then args = s_sub(args, 2, -2); end

			if func == "each" and tmpl and st.is_stanza(value) then
				if not args then value, args = root, path; end
				local ns, name = s_match(args, "^(%b{})(.*)$");
				if ns then
					ns = s_sub(ns, 2, -2);
				else
					name, ns = args, nil;
				end
				if ns == "" then ns = nil; end
				if name == "" then name = nil; end
				local out, i = {}, 1;
				for c in (value):childtags(name, ns) do out[i], i = render(tmpl, c, escape, filters), i + 1; end
				value = t_concat(out);
				is_escaped = true;
			elseif func == "and" and tmpl then
				local condition = value;
				if args then condition = root:find(args); end
				if condition then
					value = render(tmpl, root, escape, filters);
					is_escaped = true;
				end
			elseif func == "or" and tmpl then
				local condition = value;
				if args then condition = root:find(args); end
				if not condition then
					value = render(tmpl, root, escape, filters);
					is_escaped = true;
				end
			elseif filters and filters[func] then
				local f = filters[func];
				if args == nil then
					value, is_escaped = f(value, tmpl);
				else
					value, is_escaped = f(args, value, tmpl);
				end
			else
				error("No such filter function: " .. func);
			end
			pipe, pos = s_match(inner, "^(|?)()", p);
		end

		if type(value) == "string" then
			if not is_escaped then value = escape(value); end
			return value
		elseif st.is_stanza(value) then
			value = value:get_text();
			if value then return escape(value) end
		end
		return ""
	end))
end

return { render = render }