target := expr
expr as target
expr -> target
target given target = expr
let target = expr
: target expr ;
Although in general "target:=exp" seems the most palatable of these to me,
there is one nice benefit to the "given" syntax:
Suppose you have a comprehension wherein you want to pass forward an
internal "state" between iterations, but not return it as the output:
In today's python, you'd to:
outputs = []
state = initial_state
for inp in inputs:
out, state = my_update_func(state)
outputs.append(state)
This could not be neatly compacted into:
state = initial_state
outputs = [out given out, state = my_update_func(inp, state) for inp in
inputs]
Or maybe:
outputs = [out given out, state = my_update_func(inp, state) for inp in
inputs given state=initial_state]
Though I agree for the much more common case of assigning a value inline "x
given x=y" seems messily redundant.
On Sat, May 12, 2018 at 10:37 PM, Stephen J. Turnbull <
[email protected]> wrote:
> David Mertz writes:
>
> > Only the BDFL has a vote with non-zero weight.
>
> "Infinitesimal" != "zero".
>
> Pedantically yours,
>
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