• Walter Bright (1/1) May 21 2009 http://www.reddit.com/r/programming/comments/8m6p0/dobbs_code_talk_its_n...
• Tim Matthews (14/15) May 21 2009 Should this change the way pure functions work. for example:
• Walter Bright (3/21) May 21 2009 No. Pure functions cannot change global state, even if that global state...

Walter Bright <newshound1 digitalmars.com> writes:

http://www.reddit.com/r/programming/comments/8m6p0/dobbs_code_talk_its_not_always_nice_to_share/

"Tim Matthews" <tim.matthews7 gmail.com> writes:

On Fri, 22 May 2009 05:37:42 +1200, Walter Bright  
<newshound1 digitalmars.com> wrote:

 http://www.reddit.com/r/programming/comments/8m6p0/dobbs_code_talk_its_not_always_nice_to_share/


Should this change the way pure functions work. for example:

module test;

int i; //tls

pure void foo(int arg)
{
	i = arg;
}

void main()
{
	foo(2);
}


  Error: pure function 'foo' cannot access mutable static data 'i'

Walter Bright <newshound1 digitalmars.com> writes:

Tim Matthews wrote:
 Should this change the way pure functions work. for example:
 
 module test;
 
 int i; //tls
 
 pure void foo(int arg)
 {
     i = arg;
 }
 
 void main()
 {
     foo(2);
 }
 
 
  Error: pure function 'foo' cannot access mutable static data 'i'

No. Pure functions cannot change global state, even if that global state 
is for one thread only.