Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Ruby Demystified: and vs. &&

blog.tinfoilsecurity.com

Post reply on HN
Print view View original

31–40 of 74 posts

Re: Ruby Demystified: and vs. &&

#31

Post by baddox »

tinco wrote: post #14
aston wrote: post #6

Not to start a language war, but this blog post demonstrates two things Python got right that Ruby got wrong. First, in Python, there's only one way to express a boolean "and". The && operator is left out. Second, this post demonstrates a danger of allowing assignment via '=' evaluate to an expression (granted with less weird precedence rules it wouldn't turn out as bad in this case).

Not to acknowledge we are at war, but allow me to react to your act of war. This article demonstrates one thing that Ruby does awesomely, and python does not at all. Wether that makes Ruby better than Python.. well yes it does, no point in being diplomatic now, we're at war! In Ruby there is only one way to express a boolean and, it goes: &&. Besides the boolean and there is also a binary operator with the name `and`…

My biggest complaint is that you called Ruby's way "intuitive."

Re: Ruby Demystified: and vs. &&

#32

Post by [deleted] »

tinco wrote: post #14
aston wrote: post #6

Not to start a language war, but this blog post demonstrates two things Python got right that Ruby got wrong. First, in Python, there's only one way to express a boolean "and". The && operator is left out. Second, this post demonstrates a danger of allowing assignment via '=' evaluate to an expression (granted with less weird precedence rules it wouldn't turn out as bad in this case).

Not to acknowledge we are at war, but allow me to react to your act of war. This article demonstrates one thing that Ruby does awesomely, and python does not at all. Wether that makes Ruby better than Python.. well yes it does, no point in being diplomatic now, we're at war! In Ruby there is only one way to express a boolean and, it goes: &&. Besides the boolean and there is also a binary operator with the name `and`…

[deleted]

Re: Ruby Demystified: and vs. &&

#33

Post by InAnEmergency »

I think I may be the last person who still thinks "and/or" are just fine for boolean expressions in Ruby.

It is true that "and/or" are not equivalent to "&&/||". But I don't find any of the arguments that we should then avoid "and/or" in favor of "&&/||" convincing.

Re: Ruby Demystified: and vs. &&

#34

Post by aardvark179 »

tinco wrote: post #14
aston wrote: post #6

Not to start a language war, but this blog post demonstrates two things Python got right that Ruby got wrong. First, in Python, there's only one way to express a boolean "and". The && operator is left out. Second, this post demonstrates a danger of allowing assignment via '=' evaluate to an expression (granted with less weird precedence rules it wouldn't turn out as bad in this case).

Not to acknowledge we are at war, but allow me to react to your act of war. This article demonstrates one thing that Ruby does awesomely, and python does not at all. Wether that makes Ruby better than Python.. well yes it does, no point in being diplomatic now, we're at war! In Ruby there is only one way to express a boolean and, it goes: &&. Besides the boolean and there is also a binary operator with the name `and`…

Both && and and are short-circuiting operators in Ruby. To eagerly evaluate both operator arguments you would need to use &.

Re: Ruby Demystified: and vs. &&

#35

Post by lmm »

danso wrote: post #7

> When I first started learning Ruby, I was excited to discover that Ruby has the keywords and and or as boolean operators. I quickly got into the habit of writing all of my boolean statements with these, instead of the more conventional && and ||, because my code became so much readable pry(main)> a = true && false pry(main)> a = true and false Hmm...I dunno, I don't think the latter is necessarily easier to read th…

I dislike using symbols, I think because they draw a mostly-arbitrary line between operators and method calls. As a scala/python fan I like to blur that line, and write code that reads as close to English as possible, so I'd write expressions like

    (user isActive) and (user.expiry before now)
and I think that really is more readable than '&&', in a way that your example obscures because you're still using '>' and 'false'.

Re: Ruby Demystified: and vs. &&

#37

Post by jabagonuts »

tinco wrote: post #14
aston wrote: post #6

Not to start a language war, but this blog post demonstrates two things Python got right that Ruby got wrong. First, in Python, there's only one way to express a boolean "and". The && operator is left out. Second, this post demonstrates a danger of allowing assignment via '=' evaluate to an expression (granted with less weird precedence rules it wouldn't turn out as bad in this case).

Not to acknowledge we are at war, but allow me to react to your act of war. This article demonstrates one thing that Ruby does awesomely, and python does not at all. Wether that makes Ruby better than Python.. well yes it does, no point in being diplomatic now, we're at war! In Ruby there is only one way to express a boolean and, it goes: &&. Besides the boolean and there is also a binary operator with the name `and`…

"which evaluates its left child, _and_ when it is true returns the value of its right child"

I like the way you put that. I always stumble for a moment when asked to explain why using "and" and "&&" interchangeably is not a good idea because it can lead to subtle bugs in your program. Maybe a mnemonic would help to remember this more easily.

    left && right is true or false, but
    left and right is right when true
or something along those lines.

Re: Ruby Demystified: and vs. &&

#38

Post by meepmorp »

Smudge wrote: post #26
meepmorp wrote: post #13

Earlier quoted context omitted.

So why have both?

Read the article.

I did. And I still don't see why you'd have both.

It seems like a landmine for someone learning the language and a place for bugs to creep in to code.

Pick one and go with it. The extra expressiveness or whatever a ruby person would call it, that comes from the alternate forms just doesn't seem worth it.

Re: Ruby Demystified: and vs. &&

#39

Post by mistercow »

tinco wrote: post #14
aston wrote: post #6

Not to start a language war, but this blog post demonstrates two things Python got right that Ruby got wrong. First, in Python, there's only one way to express a boolean "and". The && operator is left out. Second, this post demonstrates a danger of allowing assignment via '=' evaluate to an expression (granted with less weird precedence rules it wouldn't turn out as bad in this case).

Not to acknowledge we are at war, but allow me to react to your act of war. This article demonstrates one thing that Ruby does awesomely, and python does not at all. Wether that makes Ruby better than Python.. well yes it does, no point in being diplomatic now, we're at war! In Ruby there is only one way to express a boolean and, it goes: &&. Besides the boolean and there is also a binary operator with the name `and`…

>In this way it mimics the way we build sentences, that's smart. That's intuitive. That's Ruby.

The problem is that "just like English" does not always translate to "intuitive for a programming language". Programmers don't have a problem with learning a new set of rules that don't work the same as their native language, because programming isn't (and shouldn't be) like writing a letter to your computer.

The simple rule is "if it's a binary operator, it has higher precedence than assignment". That rule works for almost every binary operator in almost every language. Show me an exception (like the comma operator in C), and I'll show you an operator that confuses the hell out of most programmers.

Re: Ruby Demystified: and vs. &&

#40

Post by goatslacker »

tinco wrote: post #14
aston wrote: post #6

Not to start a language war, but this blog post demonstrates two things Python got right that Ruby got wrong. First, in Python, there's only one way to express a boolean "and". The && operator is left out. Second, this post demonstrates a danger of allowing assignment via '=' evaluate to an expression (granted with less weird precedence rules it wouldn't turn out as bad in this case).

Not to acknowledge we are at war, but allow me to react to your act of war. This article demonstrates one thing that Ruby does awesomely, and python does not at all. Wether that makes Ruby better than Python.. well yes it does, no point in being diplomatic now, we're at war! In Ruby there is only one way to express a boolean and, it goes: &&. Besides the boolean and there is also a binary operator with the name `and`…

This explanation is an excellent way to teach and vs &&.
Post reply on HN