Hello James,
You can try :database($db)
Look at this http://design.perl6.org/S02.html#Adverbial_Pair_forms
I've found it very useful!
James E Keenan writes:
> Yesterday I made my first attempt at using any library in a Perl6
> program -- specifically, DBIish.
>
> The following succeeded in establishing a connection to a Postgresql
> database named 'hierarchy' on the same disk as Perl6:
>
> #####
> $ cat dbiish_connect.pl6
> #!/usr/bin/env perl6
> use DBIish;
>
> my $dbh = DBIish.connect("Pg", :database<hierarchy>);
>
> say "Database: connection ", ($dbh.ping ?? "established" !! "not
> established");
>
> $ perl6 dbiish_connect.pl6
> Database: connection established
> #####
>
> Since I have several different Postgresql databases on disk, I want to
> be able to store a DB's name in a variable, then have DBIish.connect
> interpolate that variable while establishing a connection. I tried:
>
> #####
> $ cat dbiish_connect_dynamic.pl6
> #!/usr/bin/env perl6
> use DBIish;
>
> my $db = 'hierarchy';
> my $dbh = DBIish.connect("Pg", :database<$db>);
>
> say "Database $db: connection ", ($dbh.ping ?? "established" !! "not
> established");
> #####
>
> But I only got this error output:
>
> #####
> $ perl6 dbiish_connect_dynamic.pl6
> DBDish::Pg: Can't connect: FATAL: database "$db" does not exist
> (1)
> in block at
> /home/jkeenan/rakudo-star/share/perl6/site/sources/3EA876C6AC912AF3692CEF8EEF5E9033C03F7507
> (DBIish) line 41
> in any at
> /home/jkeenan/.perl6/precomp/D7820A4EF6D97B780F45CAC4B50C4E6E59589690.1462056119.68849/3E/3EA876C6AC912AF3692CEF8EEF5E9033C03F7507
> line 1
> in method connect at
> /home/jkeenan/rakudo-star/share/perl6/site/sources/C2BC378F86912AB748EF3CF51FBE6E3AE0CFE0EA
> (DBDish::Pg) line 79
> in method connect at
> /home/jkeenan/rakudo-star/share/perl6/site/sources/3EA876C6AC912AF3692CEF8EEF5E9033C03F7507
> (DBIish) line 45
> in block <unit> at dbiish_connect_dynamic.pl6 line 5
> #####
>
> I also tried:
>
> #####
> $ cat dbiish_connect_dynamic_2.pl6
> #!/usr/bin/env perl6
> use DBIish;
>
> my $db = 'hierarchy';
> my $dbh = DBIish.connect("Pg", ":database<$db>");
>
> say "Database $db: connection ", ($dbh.ping ?? "established" !! "not
> established");
> #####
>
> But that gave me a different error:
>
> #####
> $ perl6 dbiish_connect_dynamic_2.pl6
> Too many positionals passed; expected 2 arguments but got 3
> in method connect at
> /home/jkeenan/rakudo-star/share/perl6/site/sources/3EA876C6AC912AF3692CEF8EEF5E9033C03F7507
> (DBIish) line 29
> in block <unit> at dbiish_connect_dynamic_2.pl6 line 5
> #####
>
> Why does variable interpolation not work here? What part is my doing
> something wrong? What part is a limitation in the DBIish library?
>
> Thank you very much.
> Jim Keenan
