Re: @safe question

[Paul Backus via Digitalmars-d-learn]

On Monday, 10 January 2022 at 01:16:31 UTC, forkit wrote:

On Sunday, 9 January 2022 at 21:56:05 UTC, Salih Dincer wrote:


Try the @trusted and in/out:
...
..
.


thanks for introducing me to the in/out feature of D :-)

I'll certainly look into that feature more.

But my question still remains:

//pointers ~=  // why is this *not* allowed in @safe
pointers ~= [i]; // while this *is* allowed in @safe


Taking the address of a local variable is forbidden in @safe 
code. Even though str is a ref variable that points to a 
heap-allocated string, it is still considered a local variable 
because it is declared inside the body of a function.

Re: @safe question

[forkit via Digitalmars-d-learn]

On Sunday, 9 January 2022 at 21:56:05 UTC, Salih Dincer wrote:


Try the @trusted and in/out:
...
..
.


thanks for introducing me to the in/out feature of D :-)

I'll certainly look into that feature more.

But my question still remains:

//pointers ~=  // why is this *not* allowed in @safe
pointers ~= [i]; // while this *is* allowed in @safe

Re: @safe question

[Salih Dincer via Digitalmars-d-learn]

On Sunday, 9 January 2022 at 20:58:05 UTC, forkit wrote:
Do not understand why one line is not considered @safe, but the 
other is.


//

module test;

import std;

@safe void main()
{
immutable string[] strings = ["one", "one", "two"];

immutable(string)*[] pointers = null;

foreach(size_t i, ref str; strings)
{
if(str == "one")
{
//pointers ~=  // not allowed in @safe ??

pointers ~= [i]; // for @safe, I have to 
revert to using an index into strings.

}
i++;
}
}

//-


Try the @trusted and in/out:

```d
auto pro(in immutable string[]   strings,
out immutable(string)*[] pointers) @trusted {
foreach(i, ref str; strings)
{
if(str == "one")
{
//pointers ~= [i]/* ok
pointers ~= //*/
}
/* unnecessary:
i++;//*/
}
}

@safe void main()
{
immutable string[] strings = ["one", "one", "two"];

immutable(string)*[] pointers = null;

strings.pro(pointers);

assert(pointers[0] ==
   [0]); // ok

assert(pointers[1] ==
   [1]); // ok

}
```

@safe question

[forkit via Digitalmars-d-learn]

Do not understand why one line is not considered @safe, but the 
other is.


//

module test;

import std;

@safe void main()
{
immutable string[] strings = ["one", "one", "two"];

immutable(string)*[] pointers = null;

foreach(size_t i, ref str; strings)
{
if(str == "one")
{
//pointers ~=  // not allowed in @safe ??

pointers ~= [i]; // for @safe, I have to 
revert to using an index into strings.

}
i++;
}
}

//-

Re: srand in D

[kdevel via Digitalmars-d-learn]

On Sunday, 9 January 2022 at 03:15:02 UTC, Ali Çehreli wrote:

What would work in the code above is 'choice':

  char q = choice(allowed_chars);

But that hits another fact of D: arrays of chars are strings, 
which cannot be RandomAccessRange because individual chars must 
be decoded to form dchars.


One can use explicit index notation which is nearly as compact as 
the template parameter form:


   string salt = iota (0, 16)
  .map!(i => saltchars [uniform(0, $)])
  .array;