4 ms·

I've used one or two of these before, would be interested in more patterns that use, methodcaller (I think in the example given str.strip would have worked too)

by stuaxo 5y ago

I've used one or two of these before, would be interested in more patterns that use, methodcaller (I think in the example given str.strip would have worked too).

mjw1007 5y ago
In my experience methodcaller is an occasionally-useful "mid-refactoring feature". That is, sometimes when I'm making a largeish modification there's a point in the commit series where the natural way to express what's going on involves using methodcaller, then by the time the work is finished the use has gone away again.
klyrs 5y ago
methodcaller can be useful in functional programming, like close_file = methodcaller('close') exhaust(map(close_file, files)) where exhaust is a function that consumes an iterator. Obviously this is a contrived example, but it's a weird transformation -- it turns map from 'call this function on each of a sequence of arguments' to, roughly 'call each of this sequence of functions on a fixed argument'
- xrisk 5y ago
  exhaust((file.close() for file in files)) works.
  - klyrs 5y ago
    Like I said, contrived example. Though, it's a specific example of a more general pattern where you have a bunch of objects that you need to send a message to. You might use this for event handling in the guts of a game engine.
  - elteto 5y ago
    I believe exhaust(file.close() for file in files) should work as well, no need for the extra parens.
- wruza 5y ago
  It’s higher order for the sake of higher order, and unreadable as hell when you return to five full pages of this nonsense a year later. These getter-caller generators are cool to show off, but irl the most naturally readable form is either a plain anonymous function, or a special form suggested by a sibling commenter. Both by a compiler easily readable by a human unreadable out of purely functional languages by design this high fashion came.
  - klyrs 5y ago
    Sometimes you need to do higher order stuff (or, maybe you don't? But it exists for good reason) Do you think it's better to use a conceptually difficult example to showcase a high order function? Or do you think it's better to show an example where the reader can accurately understand the concept and focus on what the function does?

by stuaxo 5y ago

I've used one or two of these before, would be interested in more patterns that use, methodcaller (I think in the example given str.strip would have worked too).

mjw1007 5y ago

In my experience methodcaller is an occasionally-useful "mid-refactoring feature". That is, sometimes when I'm making a largeish modification there's a point in the commit series where the natural way to express what's going on involves using methodcaller, then by the time the work is finished the use has gone away again.

klyrs 5y ago

methodcaller can be useful in functional programming, like close_file = methodcaller('close') exhaust(map(close_file, files)) where exhaust is a function that consumes an iterator. Obviously this is a contrived example, but it's a weird transformation -- it turns map from 'call this function on each of a sequence of arguments' to, roughly 'call each of this sequence of functions on a fixed argument'

xrisk 5y ago
exhaust((file.close() for file in files)) works.
- klyrs 5y ago
  Like I said, contrived example. Though, it's a specific example of a more general pattern where you have a bunch of objects that you need to send a message to. You might use this for event handling in the guts of a game engine.
- elteto 5y ago
  I believe exhaust(file.close() for file in files) should work as well, no need for the extra parens.
wruza 5y ago
It’s higher order for the sake of higher order, and unreadable as hell when you return to five full pages of this nonsense a year later. These getter-caller generators are cool to show off, but irl the most naturally readable form is either a plain anonymous function, or a special form suggested by a sibling commenter. Both by a compiler easily readable by a human unreadable out of purely functional languages by design this high fashion came.
- klyrs 5y ago
  Sometimes you need to do higher order stuff (or, maybe you don't? But it exists for good reason) Do you think it's better to use a conceptually difficult example to showcase a high order function? Or do you think it's better to show an example where the reader can accurately understand the concept and focus on what the function does?