• Charlie (7/7) Dec 05 2006 The following fails with : Error: "" is not an lvalue
• BCS (10/21) Dec 05 2006 What would this do?
• Charlie (5/31) Dec 05 2006 Yea I was trying to abuse it, you're right it shouldn't work with
• BCS (12/19) Dec 05 2006 Are you looking for some sort of "stuff in a throw away value" feature?
• Charlie (3/27) Dec 05 2006 Yes thats what I was looking for :).

Charlie <charlies nowhere.com> writes:

The following fails with : Error: "" is not an lvalue

void f( inout char [] x = "" ){ }

void main ()
{
   f();
}


Why is this not allowed ?

BCS <BCS pathilink.com> writes:

Charlie wrote:
 The following fails with : Error: "" is not an lvalue
 
 void f( inout char [] x = "" ){ }
 
 void main ()
 {
   f();
 }
 
 
 Why is this not allowed ?

What would this do?

void f( inout char [] x = "" )
{
	x = "world";
}

It amounts to "take a literal reference to a static string and set it to 
something else". It doesn't really have a meaning.

You could try shelling it by hand.

void f() { char[] x = null; f(x);}

Charlie <charlies nowhere.com> writes:

Yea I was trying to abuse it, you're right it shouldn't work with 
default parameters, what I was really trying to do was something like

char [] x = char[]

Charlie

BCS wrote:
 Charlie wrote:
 The following fails with : Error: "" is not an lvalue

 void f( inout char [] x = "" ){ }

 void main ()
 {
   f();
 }


 Why is this not allowed ?

 
 What would this do?
 
 void f( inout char [] x = "" )
 {
     x = "world";
 }
 
 It amounts to "take a literal reference to a static string and set it to 
 something else". It doesn't really have a meaning.
 
 You could try shelling it by hand.
 
 void f() { char[] x = null; f(x);}

BCS <BCS pathilink.com> writes:

Charlie wrote:
 Yea I was trying to abuse it, you're right it shouldn't work with 
 default parameters, what I was really trying to do was something like
 
 char [] x = char[]
 
 Charlie
 

Are you looking for some sort of "stuff in a throw away value" feature?

void foo(int i, inout char[] foo = /** somthing **/ )
{
	foo = "hello";
}

char[] a;
foo(1, a);
assert(a == "hello");
foo(1); // no side effects

What would be nice would be something like "Non l-values used for inout 
parameters get passed as copies and discarded after use."

Charlie <charlies nowhere.com> writes:

BCS wrote:
 Charlie wrote:
 Yea I was trying to abuse it, you're right it shouldn't work with 
 default parameters, what I was really trying to do was something like

 char [] x = char[]

 Charlie

 
 Are you looking for some sort of "stuff in a throw away value" feature?
 
 void foo(int i, inout char[] foo = /** somthing **/ )
 {
     foo = "hello";
 }
 
 char[] a;
 foo(1, a);
 assert(a == "hello");
 foo(1); // no side effects
 
 What would be nice would be something like "Non l-values used for inout 
 parameters get passed as copies and discarded after use."
 

Yes thats what I was looking for :).

Charlie