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- /*=============================================================================
- Copyright (c) 2011 Thomas Heller
- Distributed under the Boost Software License, Version 1.0. (See accompanying
- file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
- ==============================================================================*/
- #include <boost/phoenix/core.hpp>
- #include <boost/phoenix/statement.hpp>
- #include <boost/phoenix/operator.hpp>
- #include <boost/phoenix/scope.hpp>
- #include <iostream>
- #include <boost/phoenix/scope/this.hpp>
- template <typename T0>
- void f(T0 t)
- {
- std::cout << t(1) << "\n";
- std::cout << t(2) << "\n";
- std::cout << t(3) << "\n";
- std::cout << t(4) << "\n";
- std::cout << t(5) << "\n";
- std::cout << t(6) << "\n";
- std::cout << t(7) << "\n";
- }
- template <typename T0>
- void f_2(T0 t)
- {
- for(int i = 0; i < 10; ++i)
- {
- for(int j = 0; j < i; ++j)
- {
- std::cout << t(i, j) << " ";
- }
- std::cout << "\n";
- }
- }
- int main()
- {
- //using boost::phoenix::_this;
- using boost::phoenix::if_;
- using boost::phoenix::if_else;
- using boost::phoenix::val;
- using boost::phoenix::let;
- using boost::phoenix::nothing;
- using boost::phoenix::arg_names::_1;
- using boost::phoenix::arg_names::_2;
- using boost::phoenix::local_names::_a;
- f((
- if_(_1 == 0)
- [
- std::cout << val("\n")
- ]
- .else_
- [
- std::cout << _1 << " "
- , this_(_1 - 1)
- ]
- , val(0)
- ));
- /*
- f((
- if_else(
- _1 == 0
- , _1
- ,this_(_1 - 1)
- )
- ));
- */
- f((
- if_else(
- _1 != 0
- ,this_(_1 - 1)
- , _1
- )
- ));
- /*
- f(( // fac(n) = n * fac(n-1); fac(1) = 1
- if_else(
- _1 <= 1
- , 1
- , _1 * _this(_1 - 1)
- )
- ));
-
- f(( // fac(n) = n * fac(n-1); fac(1) = 1
- if_else(
- _1 > 1
- , let(_a = _this(_1-1))[_1 * _a]
- , 1
- )
- ));
-
- f(( // fib(n) = fib(n-1) + fib(n-2); fib(0) = 0; fib(1) = 1
- if_else(
- _1 == 0
- , 0
- , if_else(
- _1 == 1
- , 1
- , _this(_1 - 1) + _this(_1 - 2)
- )
- )
- ));
- f_2(( // bin(n, k) = bin(n-1, k-1) + bin(n-1, k); bin(n, 0) = 1; bin(0, k) = 0
- if_else(
- _1 == 0
- , 0
- , if_else(
- _2 == 0
- , 1
- , _this(_1 - 1, _2 - 1) + _this(_1 - 1, _2)
- )
- )
- ));
- */
- }
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