A possible lazy evaluation system?

[Stephen Horne]

I one mentioned that I thought it was sensible to label function
parameters in some way to modify the call mechanism. The obvious
analogy is 'var' parameters in Pascal, though I was thinking more of a
'lazy' modifier.

It occured to me that, instead of a fully lazy parameter system, a
simpler approach may be to lable parameters as lambdas.

You could then write something like...

  def IF (c, lambda x, lambda y) :
    if c :
      return x ()
    else :
      return y ()

...and call it with...

  IF (y != 0, x/y, 1000000)

The 'lambda' asserts that the parameters expression gets converted to
a parameterless lambda instead of being evaluated immediately.

The same notation in declarations of __call__ could provide the same
capability to all callables.

The question is - is this a sane suggestion?