Thanks Bruce,
This is great, and It works as I expected.
I appreciate all the helps.
Regards
Xin
> On Jun 4, 2018, at 9:04 AM, Bruce Gray <robertbrucegr...@gmail.com> wrote:
>
>
>> On Jun 3, 2018, at 7:41 PM, Xin Cheng <xinchen...@gmail.com> wrote:
>>
>> I am trying to make a program to do grep with perl6 regular expression, and
>> I would like to colorize the matched part to the terminal.
> —snip--
>> if $temp ~~ s/ (<$pattern>) /\\x1b\[31m$0\\x1b\[0m/ {say $temp}
>
> —snip—
>
> Change this: s/ (<$pattern>) /\\x1b\[31m$0\\x1b\[0m/
> to this: s/ (<$pattern>) /\x1b[31m$0\x1b[0m/
> and your example code will correctly highlight the pattern in the (terminal)
> output.
>
> The doubled backslash in your original code becomes a literal backslash;
> “\\x1b” is 4 characters long, “\x1b” is 1 character long (the escape
> character). Also, you would need to back-whack the `[` only on the left-hand
> side of `s///` (the pattern, which uses Regex syntax), not on the right-hand
> side (the replacement, which uses double-quoted string syntax).
>
> If you do not want to use Terminal::ANSIColor, I recommend that you save
> yourself some future confusion by isolating your escape sequences, like so:
>
> constant $color_red = "\e[31m";
> constant $color_off = "\e[0m";
>
> sub MAIN ( Str $pattern, Str $filename ) {
> for $filename.IO.lines -> $line {
> my Str $temp = $line;
>
> # if no <> surrounding $pattern it becomes literal.
> if $temp ~~ s/ (<$pattern>) /$color_red$0$color_off/ {
> say $temp;
> }
> }
> }
>
> —
> Hope this helps,
> Bruce Gray (Util of PerlMonks)
>
>
