Re: Exactly what is type match?

[ToddAndMargo via perl6-users]

El jue., 20 dic. 2018 21:43, ToddAndMargo via perl6-users 
<perl6-us...@perl.org <mailto:perl6-us...@perl.org>> escribió:

    Hi All,
    Exactly what is type "Match"?

    Here I want $D0..$D3 to only be strings.  And it throws a match error.

    $ p6 'my $x="11.2.3.4"; my Str $D0; my Str $D1; my Str $D2; my Str $D3;
    $x~~m{ (<:N>) [.] (\d+) [.] (\d+) [.] (\d+) }; $D0 = $0; $D1 = $1;
    $D2 =
    $2; $D3 = $3; print "$D0 $D1 $D2 $D3\n";'

    Type check failed in assignment to $D0; expected Str but got Match
    (Match.new(from => 1, made ...)
        in block <unit> at -e line 1

    Here is my work around:

    $ p6 'my $x="11.2.3.4"; my Str $D0; my Str $D1; my Str $D2; my Str $D3;
    $x~~m{ (<:N>+) [.] (\d+) [.] (\d+) [.] (\d+) }; $D0 = $0.Str; $D1 =
    $1.Str; $D2 = $2.Str; $D3 = $3.Str; print "$D0 $D1 $D2 $D3\n";'
    11 2 3 4


    Many thanks,
    -T

On 12/20/18 2:08 PM, JJ Merelo wrote:
Put a wriggly ~ in front of $0 to turn it into a Str; it's the Str 
contextualizer


Hi JJ,

You did not actually answer the question I asked.  What is type "Match"?

And I am missing something in your answer

This works:

$ p6 'my $x="11.2."; my Str $D0; my Str $D1; $x~~m{ (<:N>+) [.] (\d+) }; 
$D0 = $0.Str; $D1 = $1.Str;  print "$D0 $D1\n";'
11 2


This does not.  One with a space after the ~, one without it.

$ p6 'my $x="11.2."; my Str $D0; my Str $D1; $x~~m{ (<:N>+) [.] (\d+) }; 
$D0 ~$0; $D1 ~ $1;  print "$D0 $D1\n";'
WARNINGS for -e:
Useless use of "~" in expression "$D1 ~ $1" in sink context (line 1)
Useless use of "~" in expression "$D0 ~$0" in sink context (line 1)
Use of uninitialized value of type Str in string context.
Methods .^name, .perl, .gist, or .say can be used to stringify it to 
something meaningful.
  in block <unit> at -e line 1
Use of uninitialized value of type Str in string context.
Methods .^name, .perl, .gist, or .say can be used to stringify it to 
something meaningful.
  in block <unit> at -e line 1
Use of uninitialized value of type Str in string context.
Methods .^name, .perl, .gist, or .say can be used to stringify it to 
something meaningful.
  in block <unit> at -e line 1
Use of uninitialized value of type Str in string context.
Methods .^name, .perl, .gist, or .say can be used to stringify it to 
something meaningful.
  in block <unit> at -e line 1

I am confused,
-T