Is it possible to set the default values for the Main function's arguments?
It seems that I'm getting Range error.

>import std.stdio : writeln;
>void main(string[] args = ["asdsfasdf", "asdklfajsdk", "asdfasdfasd"]){
> 
>    writeln("", args[1]);
>}

Output:
>vaidas@vaidas-SATELLITE-L855:~/Desktop$ rdmd newfile.d
>>core.exception.RangeError@newfile.d(4): Range violation
>----------------
>??:? _d_arrayboundsp [0x555f5b79f8e9]
>??:? _Dmain [0x555f5b79e7ee]

On Thursday, 27 June 2019 at 17:05:05 UTC, Vaidas wrote:
> Is it possible to set the default values for the Main function's arguments?

No, as far as the language is concerned, a value is always being passed from the operating system, so those default values would never trigger.

What you could do though is just check inside main:

void main(string[] args) {
   if(args.length <= 1) args = ["defaults", "here"];
}


Keep in mind that args[0] is almost always set to the name of the executable, so length == 0 is liekly never going to happen.

On Thursday, 27 June 2019 at 17:05:05 UTC, Vaidas wrote:
> Is it possible to set the default values for the Main function's arguments?
> It seems that I'm getting Range error.
>
>>import std.stdio : writeln;
>>void main(string[] args = ["asdsfasdf", "asdklfajsdk", "asdfasdfasd"]){
>> 
>>    writeln("", args[1]);
>>}
>
> Output:
>>vaidas@vaidas-SATELLITE-L855:~/Desktop$ rdmd newfile.d
>>>core.exception.RangeError@newfile.d(4): Range violation
>>----------------
>>??:? _d_arrayboundsp [0x555f5b79f8e9]
>>??:? _Dmain [0x555f5b79e7ee]

consider this:

module d-program;

void main(string[] args)
{
  import std.stdio;
  writeln("args = ", args);
}

---

~/> ./d-program abc def

Output:
args = ["~/d-program", "abc", "def"]

---

~/> ./d-program

Output:

args = ["~/d-program"]

On Thursday, 27 June 2019 at 17:05:05 UTC, Vaidas wrote:
> Is it possible to set the default values for the Main function's arguments?
> It seems that I'm getting Range error.
>
>>import std.stdio : writeln;
>>void main(string[] args = ["asdsfasdf", "asdklfajsdk", "asdfasdfasd"]){
>> 
>>    writeln("", args[1]);
>>}
>
> Output:
>>vaidas@vaidas-SATELLITE-L855:~/Desktop$ rdmd newfile.d
>>>core.exception.RangeError@newfile.d(4): Range violation
>>----------------
>>??:? _d_arrayboundsp [0x555f5b79f8e9]
>>??:? _Dmain [0x555f5b79e7ee]

Your main function is receiving an empty array as an argument, which overrides the default argument.

The correct way to do what you want to do is this:

void main(string[] args)
{
    string[] defaultArgs = ["my", "default", "arguments"];
    if (args.length == 0) {
        args = defaultArgs;
    }
    // Process args...
}

On Thursday, 27 June 2019 at 17:20:37 UTC, Paul Backus wrote:
> void main(string[] args)
> {
>     string[] defaultArgs = ["my", "default", "arguments"];
>     if (args.length == 0) {
>         args = defaultArgs;
>     }
>     // Process args...
> }

Correction: you should check for `args.length == 1`, since (as Adam points out) the name of the program will be passed as args[0].

On Thursday, 27 June 2019 at 17:22:36 UTC, Paul Backus wrote:
> On Thursday, 27 June 2019 at 17:20:37 UTC, Paul Backus wrote:
>> void main(string[] args)
>> {
>>     string[] defaultArgs = ["my", "default", "arguments"];
>>     if (args.length == 0) {
>>         args = defaultArgs;
>>     }
>>     // Process args...
>> }
>
> Correction: you should check for `args.length == 1`, since (as Adam points out) the name of the program will be passed as args[0].

I'm feeling, that overwriting the zero argument that is containing the program's path is mostly never a good idea.

Here, zero argument will not be overwritten.

Program.d
>import std.stdio : writeln;
>void main(string[] args)
>{
>     string[] defaultArgs = [args[0], "default", "arguments"];
>     if (args.length == 1) {
>         args = defaultArgs;
>     }
>     // Process args...
>     writeln("", args);
> }

Output:

>vaidas@vaidas-SATELLITE-L855:~/Desktop$ rdmd program.d
>["/tmp/.rdmd-1000/rdmd-program.d-7E2D9881B29D67DB2D97D001FFD2817D/program", "default", "arguments"]