I don't understand the precedence in crystal

Help & Support
1 
Operator Precedence¶
This list is sorted by precedence, so upper entries bind stronger than lower ones.

Category	Operators
Index accessors	[], []?
Unary	+, &+, -, &-, !, ~
Exponential	**, &**
Multiplicative	*, &*, /, //, %
Additive	+, &+, -, &-
Shift	<<, >>
Binary AND	&
Binary OR/XOR	|,^
Equality and Subsumption	==, !=, =~, !~, ===
Comparison	<, <=, >, >=, <=>
Logical AND	&&
Logical OR	||
Range	.., ...
Conditional	?:
Assignment	=, []=, +=, &+=, -=, &-=, *=, &*=, /=, //=, %=, |=, &=,^=,**=,<<=,>>=, ||=, &&=
Splat	*, **

** has higher precedence than + and * why is it in the middle ?

2

Are you coming from a different language with an unusual precedence order? As far as I know it’s coming from standard math precedence and most languages follow, having exponentiation (**) higher than multiplication (*) higher than addition (+). For example the python operator precedence is quite similar

3

but look how they are sorted in the page low precedence and then higher and then low ???

4

+ here is unary operator, like this: +int

5

the list is sorted from higher precedence to lower precedence going from top to bottom. Maybe you are confused why ** appears lower than + and * despite having exponentiation having higher precedence? ** can mean two distinct things, exponentiation or splat, exponentiation has higher precedence and splat has lower

6

yes that what confuses me + higher than ** what !!! that is my confusion

7

but it should not be on top because ** is higher

8

i am really confused the precedence list is messed up

9

Operator precedence can be confusing at first, but this is not any different in crystal than in ruby or python that also have unary + operator and ** as splat operator.
unary + as in +5 meaning just positive 5 is highest
then exponentiation, ie 5**2 == 25
then + as in addition, as in 5 + 2 == 7
then ** meaning splat, as in:

tuple = {chomp: true}
gets(**tuple)
1 Like