parse source code

1 module parse;
2 
3 import brainfuck;
4 import input_stream;
5 
6 BrainfuckInstruction[] parse_brainfuck(string code) {
7     code ~= "\u0000";
8     return parse_block(new InputStream!(immutable char)(code), '\u0000');
9 }
10 
11 BrainfuckInstruction[] parse_block(InputStream!(immutable char) stream, char delimiter) {
12     BrainfuckInstruction[] insts;
13     char first_char = stream.read();
14 
15     while(first_char != delimiter) {
16         switch(first_char) {
17             case '+':
18             case '-':
19                 auto amt = first_char == '+' ? 1 : -1;
20 
21                 auto c = cast(char) stream.read();
22                 while(c == '+' || c == '-') {
23                     amt += c == '+' ? 1 : -1;
24                     c = stream.read();
25                 }
26 
27                 insts ~= new Modify(amt);
28                 stream.seek(-1);
29                 break;
30             case '>':
31             case '<':
32                 auto amt = first_char == '>' ? 1 : -1;
33 
34                 auto c = cast(char) stream.read();
35                 while(c == '>' || c == '<') {
36                     amt += c == '>' ? 1 : -1;
37                     c = stream.read();
38                 }
39 
40                 insts ~= new Select(amt);
41                 stream.seek(-1);
42                 break;
43             case '[':
44                 insts ~= new Loop(parse_block(stream, ']'));
45                 break;
46             case ',':
47                 insts ~= new Input();
48                 break;
49             case '.':
50                 insts ~= new Output();
51                 break;
52             default:
53                 break;
54         }
55 
56         first_char = stream.read();
57     }
58     return insts;
59 }