Using a colon in a method and function call in Perl 6

Question

I'm wondering which colons are associated with method and function calls in Perl 6. For the record, I use the version of perl6 2015.05-55-gd84bbbc built on the version of MoarVM 2015.05.

I just saw the following in the Perl6 Test spec (S32-io) (I added a comment):

$fh.print: "0123456789A";   # prints '0123456789A' to the file

As far as I can tell, this is equivalent to:

$fh.print("0123456789A");   # prints '0123456789A' to the file

Both of them seem to take a few arguments and fine-tune lists:

$fh.print: "012", "345", "6789A";   # prints '0123456789A' to the file
$fh.print("012", "345", "6789A");   # prints '0123456789A' to the file

my @a = <012 345 6789A>;

$fh.print(@a);   # prints '0123456789A' to the file
$fh.print: @a;   # prints '0123456789A' to the file

There must be some reason to have these two different syntaxes. Is there a reason to use one or the other syntax?

I also noticed that when used as a method, we should use either :or ()with print:

$fh.print(@a);   # Works
$fh.print: @a;   # Works!
$fh.print @a;    # ERROR!

print. : () :

print @a;  # Prints '0123456789A' (no newline, just like Perl 5)
print(@a); # Ditto
print: @a; # Prints '012 345 6789A' followed by a newline (at least in REPL)

print  @a, @a; # Error (Two terms in a row)
print: @a, @a; # Prints '012 345 6789A 012 345 6789A' followed by a newline (in REPL) 

script. :

print @a;

:

print: @a, @a;

:

$fh.print: @a, @a; # Prints '0123456789A0123456789A' to the file

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Answer 1

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Answer 2

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