Intro - Chapter: 0:History 1:Design 2:Basics 3:Var 4:Op 5:IO 6:Block 7:Sub 8:OOP 9:Rx 10:Meta
Overview - Appendix: A:Index B:Tables C:Cook D:Delta E:Best of F:Links G:Glossary
Perl folklore: Perl is an operator based language.
Perl 6 has a huge amount of operators, because they support 2 of the main design goals: they offer dense and readable code. 2 + 3 is certainly shorter and easier to understand then add(2,3), since pictograms can be picked up faster than words. (Fortran made his whole carrier on that). But because they are so many, they had to be sorted by a rule named huffman coding, which was applied here more than in any other part of the syntax.
To understand an operator you have to know his arity (how many parameters he takes - usually one (!) or two (+) ).
The precedence tells which operator to prefer in case of conflict, when no braces are used (round braces are only used for grouping and managing precedence). It allows 2 + 3 * 5 to return 17, not 25, which would upset your math teacher.
Behind that link is a table which also tells you also the associativity of every operator. This tells you after which rule to resolve precedence if one operator is used several times like in 2 * 3 * 7.
This is the most mighty (much more mighty than its backported Perl 5 twin) of all Perl 6 operators. It can be called the "compare-this-with-that-operator". If the left side of that infix op matches somehow the content of the right side, it returns Bool::True, otherwise Bool::False. The negated form !~ naturally works the other way around. The exact comparison operation depends on the data types of the values on both sides. Just look into that large table to check your specific case.
Smartmatching was originally invented to make matching with regex semantically sane.
~~ !~
eqv eq == ===
!= !==
++ -- succ pred
before after cmp
< == > <=> <= >=
lt eq gt leg le ge
3 < $a == $a < 7
is not the same as
3 < $a < 7
because latter is evaled at once and the first in 2 steps (left to right)
| & ^ !
any all one none
.. ^
&& - and
|| - or
// - err
^^ - xor
see also numerical selection
?? !!
ff fff
...
???
!!!
? !
?& ?| ?^
+ - * ** / % %%
+& +| +^ +< +>
mod exp sqrt sin cos tan log log10
min max minmax
~ x
~& ~| ~^ ~< ~>
The simplest way to create a list is by repeating some values:
'munch' xx 3 # results in 'munch', 'munch', 'munch'
('hallo', 'echo') xx 2 --> 'hallo', 'echo', 'hallo', 'echo'
In list context the range operator produces lists:
@ 2 .. 7 --> 2,3,4,5,6,7
...
Z
X
<< >>
[ ]
[\ ]
<== ==>
<<== ==>>
Intro - Chapter: 0:History 1:Design 2:Basics 3:Var 4:Op 5:IO 6:Block 7:Sub 8:OOP 9:Rx 10:Meta
Overview - Appendix: A:Index B:Tables C:Cook D:Delta E:Best of F:Links G:Glossary