Today's revised revision of yesterday's new revisions
with amendments!
:-)
perl 6: method:
12/10/2019
perl 6: method:
12/10/2019
Also: "starts-with" and "ends-with"
A method is a routine that you feed: .foo
$ p6 'say "abc".contains( "a" );'
True
$ p6 'say "abc".contains( "z" );'
False
$ p6 'my $x="\na\nb\nc\n"; for $x.lines -> $i {print "<$i>\n"};'
<>
<a>
<b>
<c>
Case insensitive contains:
if "2018 Jul 7".fc.contains( "jul".fc ) {say "Yes";}
Yes
if "2018 xJul 7".fc.contains( "jul".fc ) {say "Yes";}
Yes
if "2018 xul 7".fc.contains( "jul".fc ) {say "Yes";}
<nothing>
Warning: in the following, use "none" not "not" to negate if
"coming soon"
is found. "not" will always return False.
my $x="strong>2018.2.0; Coming Soon</strong>"; say so
$x.fc.contains("strong" & none "coming soon");
False
multi method contains(Str:D: Cool:D $needle, Int(Cool:D) $pos --> Bool)
"multi method"
This means there are multiple ways to address this, as in
multi method contains(Str:D: Cool:D $needle --> Bool)
multi method contains(Str:D: Str:D $needle --> Bool)
multi method contains(Str:D: Cool:D $needle, Int(Cool:D) $pos
--> Bool)
multi method contains(Str:D: Str:D $needle, Int:D $pos --> Bool)
"Str"
is the string data (Haystack) that will be operated on by the
method (contains)
":D"
means it wants actual data in the string and not a Nil.
The jargon for this requirement is that is is constrained
to an actual value
If it wanted a Nil, it would say ":U" or constrained to
a Nil
":"
is the delimiter that tells you it is finished defining
what is wants to be fed
"Cool:D $needle"
means it wants a type Cool (string or number) for the
substring ($needle) it is looking for in the Haystack (Str)
"Int(Cool:D)"
Means it will change a type Cool into a type Int (integer)
and the ":D" means it want some actual data and not a Nil.
"$pos"
Is short of Position. It is the starting index in the
haystack (Str) to start looking for the substring
(needle). Index starts at zero by way of string
convention in Perl 6
$pos is an optional parameter. Instead of $pos?
for optional, they stated it with several "multi method"
that do not include $pos.
"-->Bool"
means it return True or False
