Hi Erik, I have changed my proposal to the alternative syntax a:: b (Note my preferred spacing. This is to make it read like some annoation applied to the expression, like delayed:: expensive_function()+1 ) Since :: is a binary operator, we need to think about associativity. My conservative proposal would be to make it non-associative, you would have to write explicitly a:: (b:: c) or (a:: b):: c Stephan Op 17 feb. 2017 22:35 schreef "Erik" <python@lucidity.plus.com>: On 17/02/17 10:22, Stephan Houben wrote:

Proposal: Light-weight call-by-name syntax in Python

The following syntax a : b is to be interpreted as: a(lambda: b)

Isn't this too general a syntax? Doesn't it lead to something like: if a: b: c: d: e: pass E.