5 ms·

Python uses * * , but that is ambigous with int a = 1; int *b = &a; int c = a ** b; // Am I casting b to an int (returning it's address) and exponentin

Python uses * * , but that is ambigous with int a = 1; int *b = &a; int c = a ** b; // Am I casting b to an int (returning it's address) and exponenting it or am I derefrencing b and multiplying it's result with a?

userbinator 9y ago
I suppose ^^ might work, although a little odd because by consistency it would otherwise be the "logical XOR", a mythical operator that doesn't actually make much sense.
- poizan42 9y ago
  > a mythical operator that doesn't actually make much sense. Hmm I'm pretty sure practically every programming languages have it. It usually looks like "!=" or "<>". The even more obscure logical XNOR is usually denoted "==" or "="
  - danharaj 9y ago
    Not quite..
  - kazagistar 9y ago
    Alas, this doesn't deal with the idea of truthyness as a proper logocal XOR would, so it is incorrect in many of the most popular languages, including C, where a value that is true is not always equal to another value that is true. This only works in the much more strongly typed languages, or when you force cast both sides to a boolean with something like !!
  - opejn 9y ago
    Yes! In C its full spelling is "!a != !b".
- theOnliest 9y ago
  Perl has logical xor, which is occasionally useful. I usually reach for it when argument checking, where it makes sense to have either this param or that but not both.
wkz 9y ago
How would this be different from &? It is also a unary operator and && is a different binary operator. '||' and '&&' are distinct tokens in C as far as i know, i.e. not handled as two consecutive '|'s or '&'s. So your example would unambiguously be parsed as "a to the b:th power". Whereas the other case would need explicit parens: int c = a * (*b); Similar example for &: int a = 1; int b = 1 && a; /* 1 LOGICAL_AND a */ int c = 1 & (&a); /* 1 AND address of a */
- mafuy 9y ago
  Just dropping in to say you are completely correct. It is called "maximum munch" and mandated by the C spec. I recently wrote a toy C compiler and was confused until I learned this.

userbinator 9y ago

I suppose ^^ might work, although a little odd because by consistency it would otherwise be the "logical XOR", a mythical operator that doesn't actually make much sense.

poizan42 9y ago
> a mythical operator that doesn't actually make much sense. Hmm I'm pretty sure practically every programming languages have it. It usually looks like "!=" or "<>". The even more obscure logical XNOR is usually denoted "==" or "="
- danharaj 9y ago
  Not quite..
- kazagistar 9y ago
  Alas, this doesn't deal with the idea of truthyness as a proper logocal XOR would, so it is incorrect in many of the most popular languages, including C, where a value that is true is not always equal to another value that is true. This only works in the much more strongly typed languages, or when you force cast both sides to a boolean with something like !!
- opejn 9y ago
  Yes! In C its full spelling is "!a != !b".
theOnliest 9y ago
Perl has logical xor, which is occasionally useful. I usually reach for it when argument checking, where it makes sense to have either this param or that but not both.

wkz 9y ago

How would this be different from &? It is also a unary operator and && is a different binary operator. '||' and '&&' are distinct tokens in C as far as i know, i.e. not handled as two consecutive '|'s or '&'s. So your example would unambiguously be parsed as "a to the b:th power". Whereas the other case would need explicit parens: int c = a * (*b); Similar example for &: int a = 1; int b = 1 && a; /* 1 LOGICAL_AND a */ int c = 1 & (&a); /* 1 AND address of a */

mafuy 9y ago
Just dropping in to say you are completely correct. It is called "maximum munch" and mandated by the C spec. I recently wrote a toy C compiler and was confused until I learned this.