Perl 6 Deep Dive

Matching a grammar

Our sample program, which will be parsed line by line in the rest of the chapter, looks like this:

my $x;$x = 5;say $x; # 5 my $y;$y = $x;say $y; # 5my $z;$z = $x + $y;say $z; # 10

This is a valid Perl 6 program, and we have to create the grammar that parses and executes it.

Let us save the reference program in a separate file, say, refer.pl, and use the parsefile method instead of the parse one:

my $result = G.parsefile('refer.pl');say $result;

This program prints the whole content of the file, as the TOP rule still matches with everything it gets. To make sure the grammar is parsing the whole file, let us add anchors to tie the beginning and the end of the text:

grammar G {    rule TOP {        ^ .* $    }}

You may feel free ...