Re: How do you reference variables in an AA of Variants?

[Wyatt via Digitalmars-d-learn]

On Tuesday, 9 February 2016 at 03:49:11 UTC, Enjoys Math wrote:

This:   
double b = 1.0;

Variant[string] aa = ["b": ];

writeln(aa["b"]);

fails with:

Error: cannot implicitly convert expression(["b":]) of type 
double*[string] to VariantN!20u[string]


Helps please!


I've found bugbears like this are distressingly common in 
std.variant.  Another one you might find yourself dealing with is 
https://issues.dlang.org/show_bug.cgi?id=10223, which applies to 
AAs as much as regular arrays.  It's actually why I stopped using 
it in favour of Adam Ruppe's arsd.jsvar.


-Wyatt

Re: How do you reference variables in an AA of Variants?

[Basile B. via Digitalmars-d-learn]

On Tuesday, 9 February 2016 at 03:49:11 UTC, Enjoys Math wrote:

This:   
double b = 1.0;

Variant[string] aa = ["b": ];

writeln(aa["b"]);

fails with:

Error: cannot implicitly convert expression(["b":]) of type 
double*[string] to VariantN!20u[string]


Helps please!


Use an intermediate to carry the result of &:

double b = 1.0;
Variant vb = 
Variant[string] aa = ["b": vb];
writeln(aa["b"]);

 is a rvalue.
vb is a lvalue.

Re: How do you reference variables in an AA of Variants?

[Ali Çehreli via Digitalmars-d-learn]

On 02/08/2016 07:49 PM, Enjoys Math wrote:

This:
 double b = 1.0;

 Variant[string] aa = ["b": ];

 writeln(aa["b"]);

fails with:

Error: cannot implicitly convert expression(["b":]) of type
double*[string] to VariantN!20u[string]

Helps please!


When initializing the array, you have to use Variant():

import std.stdio;
import std.variant;

void main() {
double b = 1.5;

Variant[string] aa = ["b": Variant()];

writeln(aa);
writeln(aa["b"]);
writeln(*aa["b"].get!(double*));
}

Prints something like the following:

["b":7FFD0104B100]
7FFD0104B100
1.5

Ali

How do you reference variables in an AA of Variants?

[Enjoys Math via Digitalmars-d-learn]

This:   
double b = 1.0;

Variant[string] aa = ["b": ];

writeln(aa["b"]);

fails with:

Error: cannot implicitly convert expression(["b":]) of type 
double*[string] to VariantN!20u[string]


Helps please!