28{
33 typedef typename compositor_t::function function_t;
34
35 T x = T(0);
36
37 compositor_t compositor;
38
39 compositor.add(
40 function_t("fibonacci")
41 .var("x")
42 .expression
43 (
44 " switch "
45 " { "
46 " case x == 0 : 0; "
47 " case x == 1 : 1; "
48 " default : "
49 " { "
50 " var prev := 0; "
51 " var curr := 1; "
52 " while ((x -= 1) > 0) "
53 " { "
54 " var temp := prev; "
55 " prev := curr; "
56 " curr += temp; "
57 " }; "
58 " }; "
59 " } "
60 ));
61
62 symbol_table_t& symbol_table = compositor.symbol_table();
63 symbol_table.add_constants();
64 symbol_table.add_variable("x",x);
65
66 std::string expression_str = "fibonacci(x)";
67
68 expression_t expression;
69 expression.register_symbol_table(symbol_table);
70
71 parser_t parser;
72 parser.compile(expression_str,expression);
73
74 for (std::size_t i = 0; i < 40; ++i)
75 {
76 x = static_cast<T>(i);
77
78 const T result = expression.value();
79
80 printf("fibonacci(%3d) = %10.0f\n",
81 static_cast<int>(i),
82 result);
83 }
84}
