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digitalmars.D.learn - __traits, compile time member type info

reply "Lloyd Dupont" <ld-REMOVE galador.net> writes:
I'm trying to build an introspection system for a project I have.
I already have a working template to get members value
=== working members getter ===
Variant GETTER(T, string member)(Object target)
{
    T tt = cast(T)target;
    if (!tt)
        throw new ReflectionException("target is null or not " ~T.stringof 
~" value: " ~target.toString());
    return Variant(__traits(getMember, tt, member));
}
===========================

Now I'm trying to implement a working setter. I have a problem for testing 
and converts the value.
Ideally I'd like something like the code below
===== not compiling setter ====
void SETTER(T, string member)(Object target, Variant value)
{
    T tt = cast(T)target;
    if (!tt)
        throw new ReflectionException("target is null or not " ~T.stringof 
~" value: " ~target.toString());

    if(!value.convertsTo!( typeid(__traits(getMember, T, member))) )
        throw new ReflectionException("Can't convert " ~value.stringof ~" to 
" ~typeid(__traits(getMember, T, member)).toString());
    __traits(getMember, tt, member) = value.coerce( 
typeid(__traits(getMember, T, member)) );
}
==========================

it doesn't compile because I don't know how to get the type, at compile 
time, of member "member" of type "T"
how do I do that please?
Jun 16 2011
next sibling parent "Lloyd Dupont" <ld-REMOVE galador.net> writes:
work with typeinfo!! :)

=====
void SETTER(T, string member)(Object target, Variant value)
{
    T tt = cast(T)target;
    if (!tt)
        throw new ReflectionException("target is null or not " ~T.stringof 
~" value: " ~target.toString());

    if(!value.convertsTo!( typeof(__traits(getMember, T, member)) ))
        throw new ReflectionException("Can't convert " ~value.stringof ~" to 
" ~typeof(__traits(getMember, T, member)).stringof);
    __traits(getMember, tt, member) = value.coerce!( 
typeof(__traits(getMember, T, member)) );
}
======
Jun 16 2011
prev sibling parent "Lloyd Dupont" <ld-REMOVE galador.net> writes:
works with typeinfo!

void SETTER(T, string member)(Object target, Variant value)
{
    T tt = cast(T)target;
    if (!tt)
        throw new ReflectionException("target is null or not " ~T.stringof 
~" value: " ~target.toString());

    if(!value.convertsTo!( typeof(__traits(getMember, T, member)) ))
        throw new ReflectionException("Can't convert " ~value.stringof ~" to 
" ~typeof(__traits(getMember, T, member)).stringof);
    __traits(getMember, tt, member) = value.coerce!( 
typeof(__traits(getMember, T, member)) );
}




"Lloyd Dupont"  wrote in message news:itcthc$1onk$1 digitalmars.com...

I'm trying to build an introspection system for a project I have.
I already have a working template to get members value
=== working members getter ===
Variant GETTER(T, string member)(Object target)
{
    T tt = cast(T)target;
    if (!tt)
        throw new ReflectionException("target is null or not " ~T.stringof
~" value: " ~target.toString());
    return Variant(__traits(getMember, tt, member));
}
===========================

Now I'm trying to implement a working setter. I have a problem for testing
and converts the value.
Ideally I'd like something like the code below
===== not compiling setter ====
void SETTER(T, string member)(Object target, Variant value)
{
    T tt = cast(T)target;
    if (!tt)
        throw new ReflectionException("target is null or not " ~T.stringof
~" value: " ~target.toString());

    if(!value.convertsTo!( typeid(__traits(getMember, T, member))) )
        throw new ReflectionException("Can't convert " ~value.stringof ~" to
" ~typeid(__traits(getMember, T, member)).toString());
    __traits(getMember, tt, member) = value.coerce(
typeid(__traits(getMember, T, member)) );
}
==========================

it doesn't compile because I don't know how to get the type, at compile
time, of member "member" of type "T"
how do I do that please?
Jun 16 2011