Thank you Larry. Regards Olivier 2013/10/2 Larry Evans <cppljevans@suddenlink.net>
On 10/02/13 12:13, Olivier Austina wrote:
Hi, this is a basic question (I am sorry). I am try to undestand the calc2_ast.cpp example at http://www.boost.org/doc/libs/**1_41_0/libs/spirit/example/qi/** calc2_ast.cpp<http://www.boost.org/doc/libs/1_41_0/libs/spirit/example/qi/calc2_ast.cpp> I think the instruction expression_ast() : expr(nil()){} is an inheritance.
expr is a member variable of expression_ast.
Where can I find the definition of expr()?
See below.
This is the code struct expression_ast { typedef boost::variant< nil // can't happen! , unsigned int , boost::recursive_wrapper<**expression_ast> , boost::recursive_wrapper<**binary_op> , boost::recursive_wrapper<**unary_op> > type;
*expression_ast() : expr(nil()){};*
template <typename Expr> expression_ast(Expr const& expr) : expr(expr) {}
expression_ast& operator+=(expression_ast const& rhs); expression_ast& operator-=(expression_ast const& rhs); expression_ast& operator*=(expression_ast const& rhs); expression_ast& operator/=(expression_ast const& rhs);
type expr;
Here's the definition of expr.
};
//expression_ast bbb; struct binary_op { binary_op( char op , expression_ast const& left , expression_ast const& right) : op(op), left(left), right(right) {}
char op; expression_ast left; expression_ast right; };
Thank you.
Regards Olivier
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