Re: How to invert bool false/true in alias compose?

[Marcone via Digitalmars-d-learn]

On Saturday, 7 December 2019 at 04:05:23 UTC, mipri wrote:

On Saturday, 7 December 2019 at 04:00:53 UTC, Marcone wrote:

import std;

alias cmd = compose!(to!bool, wait, spawnShell, to!string);

void main(){
writeln(cmd("where notepad.exe"));
}


Result:

C:\Windows\System32\notepad.exe
C:\Windows\notepad.exe
false


The result show "false" because good spawnshell command return 
0 and 0 to bool is false. But I want to invert false to true 
to get true or false if command success.


These all work:

alias cmd = compose!(unaryFun!"!a", to!bool, wait, spawnShell, 
to!string);


alias cmd = compose!("!a", to!bool, wait, spawnShell, 
to!string);


alias cmd = compose!(b => !b, to!bool, wait, spawnShell, 
to!string);


Thank you very much mipri! Work very well!

Re: How to invert bool false/true in alias compose?

[mipri via Digitalmars-d-learn]

On Saturday, 7 December 2019 at 04:00:53 UTC, Marcone wrote:

import std;

alias cmd = compose!(to!bool, wait, spawnShell, to!string);

void main(){
writeln(cmd("where notepad.exe"));
}


Result:

C:\Windows\System32\notepad.exe
C:\Windows\notepad.exe
false


The result show "false" because good spawnshell command return 
0 and 0 to bool is false. But I want to invert false to true to 
get true or false if command success.


These all work:

alias cmd = compose!(unaryFun!"!a", to!bool, wait, spawnShell, 
to!string);


alias cmd = compose!("!a", to!bool, wait, spawnShell, to!string);

alias cmd = compose!(b => !b, to!bool, wait, spawnShell, 
to!string);

Re: How to invert bool false/true in alias compose?

[Timon Gehr via Digitalmars-d-learn]

On 07.12.19 05:00, Marcone wrote:

import std;

alias cmd = compose!(to!bool, wait, spawnShell, to!string);

void main(){
 writeln(cmd("where notepad.exe"));
}


Result:

C:\Windows\System32\notepad.exe
C:\Windows\notepad.exe
false


The result show "false" because good spawnshell command return 0 and 0 
to bool is false. But I want to invert false to true to get true or 
false if command success.


alias cmd = compose!(not!(to!bool), wait, spawnShell, to!string);

How to invert bool false/true in alias compose?

[Marcone via Digitalmars-d-learn]

import std;

alias cmd = compose!(to!bool, wait, spawnShell, to!string);

void main(){
writeln(cmd("where notepad.exe"));
}


Result:

C:\Windows\System32\notepad.exe
C:\Windows\notepad.exe
false


The result show "false" because good spawnshell command return 0 
and 0 to bool is false. But I want to invert false to true to get 
true or false if command success.