File

tools/erlparse.lua @ 12580:a9dbf657c894 0.12

util.datamapper: Improve handling of schemas with non-obvious "type" The JSON Schema specification says that schemas are objects or booleans, and that the 'type' property is optional and can be an array. This module previously allowed bare type names as schemas and did not really handle booleans. It now handles missing 'type' properties and boolean 'true' as a schema. Objects and arrays are guessed based on the presence of 'properties' or 'items' field.
author Kim Alvefur <zash@zash.se>
date Fri, 08 Jul 2022 17:32:48 +0200
parent 7819:ad709ee7d3d8
line wrap: on
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-- Prosody IM
-- Copyright (C) 2008-2010 Matthew Wild
-- Copyright (C) 2008-2010 Waqas Hussain
--
-- This project is MIT/X11 licensed. Please see the
-- COPYING file in the source package for more information.
--

local string_byte, string_char = string.byte, string.char;
local t_concat, t_insert = table.concat, table.insert;
local type, tonumber, tostring = type, tonumber, tostring;

local file = nil;
local last = nil;
local line = 1;
local function read(expected)
	local ch;
	if last then
		ch = last; last = nil;
	else
		ch = file:read(1);
		if ch == "\n" then line = line + 1; end
	end
	if expected and ch ~= expected then error("expected: "..expected.."; got: "..(ch or "nil").." on line "..line); end
	return ch;
end
local function pushback(ch)
	if last then error(); end
	last = ch;
end
local function peek()
	if not last then last = read(); end
	return last;
end

local _A, _a, _Z, _z, _0, _9, __, _at, _space, _minus = string_byte("AaZz09@_ -", 1, 10);
local function isLowerAlpha(ch)
	ch = string_byte(ch) or 0;
	return (ch >= _a and ch <= _z);
end
local function isNumeric(ch)
	ch = string_byte(ch) or 0;
	return (ch >= _0 and ch <= _9) or ch == _minus;
end
local function isAtom(ch)
	ch = string_byte(ch) or 0;
	return (ch >= _A and ch <= _Z) or (ch >= _a and ch <= _z) or (ch >= _0 and ch <= _9) or ch == __ or ch == _at;
end
local function isSpace(ch)
	ch = string_byte(ch) or "x";
	return ch <= _space;
end

local escapes = {["\\b"]="\b", ["\\d"]="\127", ["\\e"]="\27", ["\\f"]="\f", ["\\n"]="\n", ["\\r"]="\r", ["\\s"]=" ", ["\\t"]="\t", ["\\v"]="\v", ["\\\""]="\"", ["\\'"]="'", ["\\\\"]="\\"};
local function readString()
	read("\""); -- skip quote
	local slash = nil;
	local str = {};
	while true do
		local ch = read();
		if slash then
			slash = slash..ch;
			if not escapes[slash] then error("Unknown escape sequence: "..slash); end
			str[#str+1] = escapes[slash];
			slash = nil;
		elseif ch == "\"" then
			break;
		elseif ch == "\\" then
			slash = ch;
		else
			str[#str+1] = ch;
		end
	end
	return t_concat(str);
end
local function readAtom1()
	local var = { read() };
	while isAtom(peek()) do
		var[#var+1] = read();
	end
	return t_concat(var);
end
local function readAtom2()
	local str = { read("'") };
	local slash = nil;
	while true do
		local ch = read();
		str[#str+1] = ch;
		if ch == "'" and not slash then break; end
	end
	return t_concat(str);
end
local function readNumber()
	local num = { read() };
	while isNumeric(peek()) do
		num[#num+1] = read();
	end
	if peek() == "." then
		num[#num+1] = read();
		while isNumeric(peek()) do
			num[#num+1] = read();
		end
	end
	return tonumber(t_concat(num));
end
local readItem = nil;
local function readTuple()
	local t = {};
	local s = {}; -- string representation
	read(); -- read {, or [, or <
	while true do
		local item = readItem();
		if not item then break; end
		if type(item) ~= "number" or item > 255 then
			s = nil;
		elseif s then
			s[#s+1] = string_char(item);
		end
		t_insert(t, item);
	end
	read(); -- read }, or ], or >
	if s and #s > 0  then
		return t_concat(s)
	else
		return t
	end;
end
local function readBinary()
	read("<"); -- read <
	-- Discard PIDs
	if isNumeric(peek()) then
		while peek() ~= ">" do read(); end
		read(">");
		return {};
	end
	local t = readTuple();
	read(">") -- read >
	local ch = peek();
	if type(t) == "string" then
		-- binary is a list of integers
		return t;
	elseif type(t) == "table" then
		if t[1] then
			-- binary contains string
			return t[1];
		else
			-- binary is empty
			return "";
		end;
	else
		error();
	end
end
readItem = function()
	local ch = peek();
	if ch == nil then return nil end
	if ch == "{" or ch == "[" then
		return readTuple();
	elseif isLowerAlpha(ch) then
		return readAtom1();
	elseif ch == "'" then
		return readAtom2();
	elseif isNumeric(ch) then
		return readNumber();
	elseif ch == "\"" then
		return readString();
	elseif ch == "<" then
		return readBinary();
	elseif isSpace(ch) or ch == "," or ch == "|" then
		read();
		return readItem();
	else
		--print("Unknown char: "..ch);
		return nil;
	end
end
local function readChunk()
	local x = readItem();
	if x then read("."); end
	return x;
end
local function readFile(filename)
	file = io.open(filename);
	if not file then error("File not found: "..filename); os.exit(0); end
	return function()
		local x = readChunk();
		if not x and peek() then error("Invalid char: "..peek()); end
		return x;
	end;
end

local _M = {};

function _M.parseFile(file)
	return readFile(file);
end

return _M;