On 04/09/2017 10:49 PM, Duarte wrote:
---------------
import std.stdio;
pure void foo()
{
debug
{
stdout.writeln("1");
}
stdout.writeln("2");
}
void main(string[] args)
{
foo();
}
---------------
Using either '-debug' or '-release', the second stdout will give an
error (Error: pure function 'main.foo' cannot access mutable static data
'stdout') which is alright by me.
The question is why the first stdout doesn't throw the same error when
compiling with the '-debug' option? Surely the issue will be the same
and the debug-statement should be satisfied.
You're allowed to break purity in debug code.
From the spec: "As a concession to practicality, a pure function can
also [...] perform impure operations in statements that are in a
ConditionalStatement controlled by a DebugCondition"
https://dlang.org/spec/function.html#pure-functions
