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|
-- Prosody IM
-- Copyright (C) 2008-2009 Matthew Wild
-- Copyright (C) 2008-2009 Waqas Hussain
--
-- This project is MIT/X11 licensed. Please see the
-- COPYING file in the source package for more information.
--
local file = nil;
local last = nil;
local function read(expected)
local ch;
if last then
ch = last; last = nil;
else ch = file:read(1); end
if expected and ch ~= expected then error("expected: "..expected.."; got: "..(ch or "nil")); 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, __, _space = string.byte("AaZz09_ ", 1, 8);
local function isAlpha(ch)
ch = string.byte(ch) or 0;
return (ch >= _A and ch <= _Z) or (ch >= _a and ch <= _z);
end
local function isNumeric(ch)
ch = string.byte(ch) or 0;
return (ch >= _0 and ch <= _9);
end
local function isVar(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 == __;
end
local function isSpace(ch)
ch = string.byte(ch) or "x";
return ch <= _space;
end
local function readString()
read("\""); -- skip quote
local slash = nil;
local str = "";
while true do
local ch = read();
if ch == "\"" and not slash then break; end
str = str..ch;
end
str = str:gsub("\\.", {["\\b"]="\b", ["\\d"]="\d", ["\\e"]="\e", ["\\f"]="\f", ["\\n"]="\n", ["\\r"]="\r", ["\\s"]="\s", ["\\t"]="\t", ["\\v"]="\v", ["\\\""]="\"", ["\\'"]="'", ["\\\\"]="\\"});
return str;
end
local function readSpecialString()
read("<"); read("<"); -- read <<
local str = "";
if peek() == "\"" then
str = readString();
elseif peek() ~= ">" then
error();
end
read(">"); read(">"); -- read >>
return str;
end
local function readVar()
local var = read();
while isVar(peek()) do
var = var..read();
end
return var;
end
local function readNumber()
local num = read();
while isNumeric(peek()) do
num = num..read();
end
return tonumber(num);
end
local readItem = nil;
local function readTuple()
local t = {};
read(); -- read { or [
while true do
local item = readItem();
if not item then break; end
table.insert(t, item);
end
read(); -- read } or ]
return t;
end
readItem = function()
local ch = peek();
if ch == nil then return nil end
if ch == "{" or ch == "[" then
return readTuple();
elseif isAlpha(ch) then
return readVar();
elseif isNumeric(ch) then
return readNumber();
elseif ch == "\"" then
return readString();
elseif ch == "<" then
return readSpecialString();
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
module "erlparse"
function parseFile(file)
return readFile(file);
end
return _M;
|
