import std.stdio;

/*
  ATTEMPT TO USE NESTED "PURE" FUNCTIONS IN A TEMPLATE.

  All works fine unless you uncomment the third line in main. If you
  do, dmd 2.032 yeilds:

  pure.d(35): Error: pure nested function 'bar' cannot access mutable
  data 'fooState'

  pure.d(36): Error: pure nested function 'bar' cannot access mutable
  data 'y'

  pure.d(47): Error: template instance pure.fooPT!(char) error
  instantiating
*/


//"pure" inner function, with concrete types - ok
pure string foo(string x, string y){
  
  string fooState;

  string bar(string x){
    fooState = "hello ";
    return x ~ y;
  }

  return fooState ~ bar(x);
}

//potentially pure (?) templated version not labled as pure - ok
immutable(T)[] fooT(T)(immutable(T)[] x, immutable(T)[] y){

  immutable(T)[] fooState;

  immutable(T)[] bar(immutable(T)[] x){
    fooState = "hello ";
    return x ~ y;
  }

  return fooState ~ bar(x);

}

//attempt to make templated version pure - no dice
pure immutable(T)[] fooPT(T)(immutable(T)[] x, immutable(T)[] y){

  immutable(T)[] fooState;

  immutable(T)[] bar(immutable(T)[] x){
    fooState = "hello ";
    return x ~ y;
  }

  return fooState ~ bar(x);

}


void main(){
  writeln(foo("p", "c"));
  writeln(fooT("p", "c"));
  //writeln(fooPT("p", "c"));