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I think lambda syntax can be a bit cumbersome, but that aside what I really miss is a clean syntax for chaining functional operations. So often I find myself th

by jpulec 10y ago

I think lambda syntax can be a bit cumbersome, but that aside what I really miss is a clean syntax for chaining functional operations. So often I find myself thinking about data in terms of 'pipelines'. i.e. in JS: _.chain(values) .map(() => {}) .flatten() .compact() .uniq() .value() vs Python where doing the same thing becomes either a nested mess of function calls or comprehensions or a for loop.

SoftwareMaven 10y ago
But that's a function of API, not the language itself. Django (and most ORMs, I believe) support that kind of behavior: MyTable.objects. filter(some_row__gt=5). exlude(other_row='q'). order_by('other_row') The Python iterable APIs have decided to use nesting rather than chaining, but you can still have an underscore-like API: https://github.com/serkanyersen/underscore.py https://github.com/serkanyersen/underscore.py The bigger problem remains: lambda functions are hideous in Python. map() will forever be ugly if you try to use it in the same way it is used in most functional languages.
- chris_7 10y ago
  This sort of API is hard to implement in Python though, because there's no formal notion of interfaces, so you cannot extend all iterables generically. So you need to use free functions (which don't read well when chained) or a wrapper object (ick).
hcrisp 10y ago
You don't like using pytoolz? Pseudocode: result = pytoolz.pipe(values, map, flatten, compact, uniq, value) # or func = pytoolz.compose(value, uniq, compact, flatten, map) results = func(values)
- Bromskloss 10y ago
  Looks interesting. How do you tell map what function to use?
  - hcarvalhoalves 10y ago
    You probably need `compose(foo, partial(map, fn), bar)`.
    - hcrisp 10y ago
      Yeah, you do this or use curried version: pytoolz.curried.map(fn)
Bromskloss 10y ago
I've been thinking that it might be nice to use chaining (though I didn't know it had a name) in ordinary mathematical notation too, writing "x f g" instead of "g(f(x))".
moosingin3space 10y ago
Elixir and F# have my favorite syntax for that: values |> map(&({})) |> flatten |> compact |> uniq Although, the closure syntax is a little clunky before you get used to it.

by jpulec 10y ago

SoftwareMaven 10y ago

But that's a function of API, not the language itself. Django (and most ORMs, I believe) support that kind of behavior: MyTable.objects. filter(some_row__gt=5). exlude(other_row='q'). order_by('other_row') The Python iterable APIs have decided to use nesting rather than chaining, but you can still have an underscore-like API: https://github.com/serkanyersen/underscore.py https://github.com/serkanyersen/underscore.py The bigger problem remains: lambda functions are hideous in Python. map() will forever be ugly if you try to use it in the same way it is used in most functional languages.

chris_7 10y ago
This sort of API is hard to implement in Python though, because there's no formal notion of interfaces, so you cannot extend all iterables generically. So you need to use free functions (which don't read well when chained) or a wrapper object (ick).

hcrisp 10y ago

You don't like using pytoolz? Pseudocode: result = pytoolz.pipe(values, map, flatten, compact, uniq, value) # or func = pytoolz.compose(value, uniq, compact, flatten, map) results = func(values)

Bromskloss 10y ago
Looks interesting. How do you tell map what function to use?
- hcarvalhoalves 10y ago
  You probably need `compose(foo, partial(map, fn), bar)`.
  - hcrisp 10y ago
    Yeah, you do this or use curried version: pytoolz.curried.map(fn)

Bromskloss 10y ago

I've been thinking that it might be nice to use chaining (though I didn't know it had a name) in ordinary mathematical notation too, writing "x f g" instead of "g(f(x))".

moosingin3space 10y ago

Elixir and F# have my favorite syntax for that: values |> map(&({})) |> flatten |> compact |> uniq Although, the closure syntax is a little clunky before you get used to it.