My old, deeply flawed mental picture had "iio" taking the role of a pointer to a value. My bright, shiny new mental picture has "iio" acting just like a C #define macro: every time I call "iio", I'm really just writing "newIORef 0". Is that what you're saying? -Rod On Oct 27, 2008, at 4:36 PM, Martijn van Steenbergen wrote:
Rodney D Price wrote:
So apparently my mental picture of an IORef as a pointer to a value is wrong. I need a new mental picture. What's going on here?
Naming the creation of a new IORef "iio" is not gonna make it return the same IORef every time you call iio. Imagine iio being expanded to its definition in your counter1 example (which is exactly what happens); would you still expect the result to be 1,1,2,3? If you want the IORef to be shared by different pieces of code, pass it around as an argument.
Kind regards,
Martijn.