28{
33 typedef typename compositor_t::function function_t;
34
36
37 symbol_table_t symbol_table;
38 symbol_table.add_function("print",print);
39
40 compositor_t compositor(symbol_table);
41
42
43 compositor.add(
44 function_t("collatz_trace")
45 .var("x")
46 .expression
47 (
48 " while (x > 1) "
49 " { "
50 " x := (x % 2 == 0) ? x / 2 : 3x + 1; "
51 " print(x); "
52 " } "
53 ));
54
55 const std::string collatz_program =
56 " x := 0; "
57 " repeat "
58 " print(x += 1); "
59 " collatz_trace(x); "
60 " print('\n\n'); "
61 " until (x > 100); "
62 " println; ";
63
64 expression_t expression;
65 expression.register_symbol_table(symbol_table);
66
67 parser_t parser;
68 parser.enable_unknown_symbol_resolver();
69 parser.compile(collatz_program,expression);
70
71 expression.value();
72}