aboutsummaryrefslogtreecommitdiffstats
path: root/tools/erlparse.lua
blob: f31436024777a4a4aad9338e11ae7b92aff64e78 (plain)
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
-- Prosody IM v0.2
-- Copyright (C) 2008 Matthew Wild
-- Copyright (C) 2008 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;