On 10/9/18 5:42 AM, Fernando Santagata wrote:
The answer Laurent Roseenfeld gave you works for read and readchars as well.
Save the following lines in a file and run it (try and change .read into
.readchars too); it will output a series of 10-byte long Buf[uint8]s,
until it reaches the end of file.
#!/usr/bin/env perl6
given $*PROGRAM-NAME.IO.open {
while my $bytes = .read: 10 {
$bytes.say;
}
}
On Tue, Oct 9, 2018 at 10:17 AM ToddAndMargo via perl6-users
<perl6-us...@perl.org <mailto:perl6-us...@perl.org>> wrote:
On 10/9/18 1:02 AM, ToddAndMargo via perl6-users wrote:
> Hi All,
>
> When reading a text file
> https://docs.perl6.org/routine/lines
> seems pretty straight forward.
>
> Question: How do I tell when I when I have
> reached the EOF (End Of File)?
>
> Many thanks,
> -T
Please expand the question to include `read` and `readchars`.
--
Fernando Santagata
Hi Frenando,
Thank you for the help!
I am not getting anywhere with `.lines`. Read the whole thing in the
first line.
$ p6 'my $fh=open "/home/linuxutil/WhoIsMySub.pl6", :r; while my $f =
$fh.lines { say "$f\n"}; $fh.close;'
#!/usr/bin/env perl6 sub f() { put &?ROUTINE.gist; }; sub abc () {
say "This subroutine's ID is ", f; print "\n"; &?ROUTINE.gist
~~ m/' '(.*?)' '\(/; my $SubName = $0; say "This subroutine is
called $SubName"; } abc;
-T
On 10/9/18 7:03 AM, Brad Gilbert wrote:
That isn't the syntax for a loop local variable in Perl 6.
You are trying to use the Perl 5 syntax, which is not going to work in Perl 6
This is the Perl 5 code you are trying to write
while( my $f = readline $fh ){ say "$f\n"}
Which actually would turn into the following by Perl 5 compiler
while( defined( my $f = readline $fh ) ){ say "$f\n"}
If you want something that works the same in Perl 6:
while $fh.get -> $f { say $f }
---
The reason you use `while` in Perl 5 is to prevent `for` from reading
the entire file before looping.
# Perl 5
# reads in entire file before doing any work on it
for my $f (readline $fh){ say $f }
# (the reason is that readline is in list context)
This is not a problem in Perl 6
# Perl 6
# loops over a Seq which only reads enough data to get the next line
for $fh.lines -> $f { say $f }
On Tue, Oct 9, 2018 at 7:49 AM ToddAndMargo via perl6-users
<perl6-us...@perl.org> wrote:
Hi Brad,
That explains it. Thank you!
-T
