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The visual difference between a ! and an l is not that great, send_email if !user.suspended? or send_email if luser.suspended? The latter could easi

The visual difference between a ! and an l is not that great, send_email if !user.suspended? or send_email if luser.suspended? The latter could easily be an aggressive dev sending abusive emails to users they dislike enough to call lusers, at first glance at least ...

SanjayMehta 4y ago
Brought back memories of alt.sysadmin.recovery.
quietbritishjim 4y ago
Perhaps a Python style spelt-out `not` for boolean negation would have been a better solution for this than `unless` in deep retrospect? send_email if not user_suspended?
- jjgreen 4y ago
  Ruby has "not", but the precedence rules between "not" and "!" differ
  - quietbritishjim 4y ago
    Well I really showed myself up as commenting on a topic that I know nothing about! :-) But that's actually ideal in this context, a really low precedence operator is exactly what you want because you can swap `unless` for `if not` without worring about extra parentheses: send_email if not user_suspended? || user_opt_out?
    - greenpeas 4y ago
      I wouldn't use this. Relying on tricky operator precedence can trip up your readers. It's better to just wrap everything in parentheses. I also use parentheses when mixing && and ||, even though their precedence relationship is (probably) more widely known. I generally avoid `not`, `and`, `or` keywords.
hnbad 4y ago
Sadly `¬` never caught on. But I suppose being visually similar to `-` isn't much better.
- Joker_vD 4y ago
  The "logical negation" sign used to have the vertical line as long as "|", so e.g. "¬A" looked more like "‾|A" but fully vertically aligned with the letter. Sadly, this glyph fell out of usage in fonts in favour of "minus with cedilla/descender".
  - jjgreen 4y ago
    I'd always understood it came from Frege's Begriffsschrift, a small descender from a horizontal line (part of a larger diagram), so like a short wide T, then lost its right arm later. Would you have some examples? (a quick google images shows nothing like that ...)
    - Joker_vD 4y ago
      It was definitely a thing in Soviet works on mathematical/symbolic logic. But here's an example from Curry [0]. As I said, it was mostly a stylistic choice. [0] https://www.google.ru/books/edition/Foundations_of_Mathematical_Logic/27dkTJFrLZIC?hl=ru&gbpv=1&dq=symbolic%20logic&pg=PA4&printsec=frontcover https://www.google.ru/books/edition/Foundations_of_Mathemati...
- tsimionescu 4y ago
  If it's not a shift+<something> key on a popular keyboard layout, it's not going to gain widespread adoption in programming.
  - housecarpenter 4y ago
    ¬ is shift+` on the most common UK keyboard layout, but yeah, it would probably need to be popular in America.
forkerenok 4y ago
Funny, when I read your point, I was sure and ready counter with an argument that code editors must highlight symbols and unary operators differently (colours, maybe spacing as well). But I just checked this on a couple of Ruby and JS highlighters and they are actually not! :scream:

SanjayMehta 4y ago

Brought back memories of alt.sysadmin.recovery.

quietbritishjim 4y ago

Perhaps a Python style spelt-out `not` for boolean negation would have been a better solution for this than `unless` in deep retrospect? send_email if not user_suspended?

jjgreen 4y ago
Ruby has "not", but the precedence rules between "not" and "!" differ
- quietbritishjim 4y ago
  Well I really showed myself up as commenting on a topic that I know nothing about! :-) But that's actually ideal in this context, a really low precedence operator is exactly what you want because you can swap `unless` for `if not` without worring about extra parentheses: send_email if not user_suspended? || user_opt_out?
  - greenpeas 4y ago
    I wouldn't use this. Relying on tricky operator precedence can trip up your readers. It's better to just wrap everything in parentheses. I also use parentheses when mixing && and ||, even though their precedence relationship is (probably) more widely known. I generally avoid `not`, `and`, `or` keywords.

hnbad 4y ago

Sadly `¬` never caught on. But I suppose being visually similar to `-` isn't much better.

Joker_vD 4y ago
The "logical negation" sign used to have the vertical line as long as "|", so e.g. "¬A" looked more like "‾|A" but fully vertically aligned with the letter. Sadly, this glyph fell out of usage in fonts in favour of "minus with cedilla/descender".
- jjgreen 4y ago
  I'd always understood it came from Frege's Begriffsschrift, a small descender from a horizontal line (part of a larger diagram), so like a short wide T, then lost its right arm later. Would you have some examples? (a quick google images shows nothing like that ...)
  - Joker_vD 4y ago
    It was definitely a thing in Soviet works on mathematical/symbolic logic. But here's an example from Curry [0]. As I said, it was mostly a stylistic choice. [0] https://www.google.ru/books/edition/Foundations_of_Mathematical_Logic/27dkTJFrLZIC?hl=ru&gbpv=1&dq=symbolic%20logic&pg=PA4&printsec=frontcover https://www.google.ru/books/edition/Foundations_of_Mathemati...
tsimionescu 4y ago
If it's not a shift+<something> key on a popular keyboard layout, it's not going to gain widespread adoption in programming.
- housecarpenter 4y ago
  ¬ is shift+` on the most common UK keyboard layout, but yeah, it would probably need to be popular in America.

forkerenok 4y ago

Funny, when I read your point, I was sure and ready counter with an argument that code editors must highlight symbols and unary operators differently (colours, maybe spacing as well). But I just checked this on a couple of Ruby and JS highlighters and they are actually not! :scream: