1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
|
-- 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;
|
