5 ms·

I prefer the laziness of PHP and Python. JavaScript threw me off with its eagerness. Took a while getting used to.

by hackaflocka 10y ago

deleted 10y ago
[deleted]
spicyj 10y ago
In what ways are PHP and Python more lazy than JS?
- RussianCow 10y ago
  I can't speak for PHP, but in Python (version 3 at least), a lot of the built-in functions that return iterators, like `map` and `range`, are lazy.
  - daveguy 10y ago
    Also in python 2.7 (and I assume py3k stuff too) conditionals also have lazy evaluation if you have the statement: if False and (fibonacci(1000)/fibonacci(1000)): print "Nope" It will immediately evaluate to False and pring "Nope" rather than checking the (fibonacci(1000)/fibonacci(1000)) portion of the conditional. EDIT: Side note, is there a shortcut for displaying code snippets within HN posts? Extra returns (what I usually use for clarification by formatting) do not display very well.
    - lfowles 10y ago
      That's not necessarily "lazy" in the normal programming context, it's specifically short-circuit evaluation in Python. Although as Wikipedia points out: "In languages that use lazy evaluation by default (like Haskell), all functions are effectively "short-circuit", and special short-circuit operators are unnecessary."
    - mastazi 10y ago
      PHP too. (if isset($foo) && $foo == 14) If $foo is not set the second boolean expression is not evaluated (short circuit evaluation). In fact, checking if isset followed by another boolean expression is very idiomatic in PHP.
    - throwanem 10y ago
      Javascript will short-circuit in && and the ternary operator, too. But that's not really the same as lazy evaluation, which both is more general and happens in a different context; ES6 generators, for example, are lazy, which means that any sequence function in which one is used is lazy as well. Indent your code snippets with a minimum of four spaces and they will be rendered as preformatted, monospaced text. Vertically adjacent lines thus indented will be rendered as a single block.
    - Buge 10y ago
      I think there is a bug in that code. It will not print Nope.
      - daveguy 10y ago
        You are right. I meant immediately evaluate False and not print Nope.

I prefer the laziness of PHP and Python. JavaScript threw me off with its eagerness. Took a while getting used to.

deleted 10y ago

[deleted]

spicyj 10y ago

In what ways are PHP and Python more lazy than JS?

RussianCow 10y ago
I can't speak for PHP, but in Python (version 3 at least), a lot of the built-in functions that return iterators, like `map` and `range`, are lazy.
- daveguy 10y ago
  Also in python 2.7 (and I assume py3k stuff too) conditionals also have lazy evaluation if you have the statement: if False and (fibonacci(1000)/fibonacci(1000)): print "Nope" It will immediately evaluate to False and pring "Nope" rather than checking the (fibonacci(1000)/fibonacci(1000)) portion of the conditional. EDIT: Side note, is there a shortcut for displaying code snippets within HN posts? Extra returns (what I usually use for clarification by formatting) do not display very well.
  - lfowles 10y ago
    That's not necessarily "lazy" in the normal programming context, it's specifically short-circuit evaluation in Python. Although as Wikipedia points out: "In languages that use lazy evaluation by default (like Haskell), all functions are effectively "short-circuit", and special short-circuit operators are unnecessary."
  - mastazi 10y ago
    PHP too. (if isset($foo) && $foo == 14) If $foo is not set the second boolean expression is not evaluated (short circuit evaluation). In fact, checking if isset followed by another boolean expression is very idiomatic in PHP.
  - throwanem 10y ago
    Javascript will short-circuit in && and the ternary operator, too. But that's not really the same as lazy evaluation, which both is more general and happens in a different context; ES6 generators, for example, are lazy, which means that any sequence function in which one is used is lazy as well. Indent your code snippets with a minimum of four spaces and they will be rendered as preformatted, monospaced text. Vertically adjacent lines thus indented will be rendered as a single block.
  - Buge 10y ago
    I think there is a bug in that code. It will not print Nope.
    - daveguy 10y ago
      You are right. I meant immediately evaluate False and not print Nope.