base adjustment outside constructor

[dafhi]

Code: Select all

'' i want to randomize properties

type myRand
  as long a = rnd
  as long b = rnd
end type


'' But, error near last line:  Base Illegal outside a CONSTRUCTOR ..

type myExtend extends myRand
  as long c
  declare sub rand_me
end type

sub myExtend.rand_me '' manual call
  dim as myRand R
  Base = R
end sub

[fxm]

Code: Select all

type myRand
  as long a = rnd
  as long b = rnd
end type

type myExtend extends myRand
  as long c
  declare sub rand_me
end type

sub myExtend.rand_me '' manual call
  dim as myRand R
  cast(myRand, this) = R
end sub

[fxm]

More compact:

Code: Select all

type myRand
  as long a = rnd
  as long b = rnd
end type

type myExtend extends myRand
  as long c
  declare sub rand_me
end type

sub myExtend.rand_me '' manual call
  cast(myRand, this) = myRand()
end sub

[dafhi]

"you cant handle the cast"

[fxm]

Another possible syntax (if the subject interests one), but a little more hacking:

Code: Select all

type myRand
  as long a = rnd
  as long b = rnd
end type

type myExtend extends myRand
  as long c
  declare sub rand_me
end type

sub myExtend.rand_me '' manual call
  cast(myRand, this).constructor()  '' cast(myRand, this) = myRand()
end sub

In the above case, there is no longer creation of a new base instance then the copy of these base member fields to the initial derived instance, but only the re-construction of the base member fields of the initial derived instance.

[dafhi]

i had no idea cast was so powerful. really great info

[fxm]

This all works because in this type of expression, 'cast' returns a real reference, not a copy.