[Python-ideas] Does jargon make learning more difficult?

[Chris Angelico]

On Wed, Aug 22, 2018 at 3:56 AM, Abe Dillon <abedillon at gmail.com> wrote:
> I've never hears someone say, "My child's name will be if it's a girl Sally
> otherwise Billy."

"My child's name depends on gender - if it's a girl, Sally, otherwise
Billy." Seems fine to me. You can always come up with something
awkward in a particular order, but it's not the order that made it
awkward.

> Consider the alternate form: <expression> with <args>  (thought there are
> many alternative possibilities)
>
> hand = sorted(cards, key=lambda card: value[card.suit] if card is not wild
> else max_value)
>
> hand = sorted(cards, by=value[card.suit]     if card is not wild else
> max_value with card)
>
> # notice how unsurprising it is that the signature is "card"

Okay, let's read that.

hand = # we're assigning this to the name 'hand'
sorted( # calling the function named 'sorted'
cards, # positional argument, whatever's in the 'cards' variable
by= # keyword argument, what comes next is the 'by' argument
value[card.suit] # subscript 'value' with 'card.suit'
if card is not wild # yep
else max_value # so we have an alternative
with card # WAIT WAIT WAIT

Once you get to 'with card', you have to go back and completely
reinterpret everything prior to that as a function. You have to scan
back and go "hang on, so exactly how much of this is getting wrapped
up into a function here?". Contrast the Python version:

hand = sorted(cards, key=lambda card: value[card.suit] if card is not
wild else max_value)

hand = # we're assigning this to the name 'hand'
sorted( # calling the function named 'sorted'
cards, # positional argument, whatever's in the 'cards' variable
key= # keyword argument, what comes next is the 'key' argument
lambda card: # a function taking one argument
value[card.suit] # subscript 'value' with 'card.suit'
if card is not wild # yep
else max_value # so we have an alternative
) # and we're done

The only part where you have to back up and change your interpretation
is when you hit "if card is not wild", which reads well enough to
justify the odd ordering. (JFTR, I wouldn't implement a deck of cards
this way. It implies that there is exactly one wild card, where many
decks of cards have at least two. In English, "card is not wild" can
be interpreted as a membership check, but in Python, it is only an
identity check; you're capitalizing on false readability by using this
notation.)

> Oh wait... Did I accidentally replace "key" with "by"? Huh... It seems to
> make more sense even though the jargon is a "key function"... Oops! ;)

I'm sure it would make even more sense if you wrote it this way:

hand = sorted(cards, by="suit")

That's how SQL works - you just name the column that you want to order
the results by. But if you think "by" is a better keyword here, start
explaining why your ordering is done with an anonymous function, not
with an attribute name.

ChrisA