From: Eric Hodel <drbrain@...7.net>
Date: 2003-09-21T07:19:32-07:00
Subject: Re: RCR: New interpreter switch


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Martin DeMello (martindemello@yahoo.com) wrote:

> One place where perl's heavy use of implicit variables scores is in
> quick one-liners from the command prompt. I think ruby would be more
> appealing in that area if it had a switch that ran the following loop:
>=20
> while gets
>   print $_.instance_eval {
>     ...
>   }
> end
>=20
> This would generalise the existing technique of mixing a few String
> methods like gsub and scan into Kernel and having them act implicitly on
> $_.

Its already got that, use ruby -h. -n and -p do those things

Additionally:

$ ri Kernel#gets
----------------------------------------------------------- Kernel::gets
     gets( aString=3D$/ ) -> aString or nil
------------------------------------------------------------------------
     Returns (and assigns to $_) the next line from the list of files in
     ARGV (or $*), or from standard input if no files are present on the
     command line. Returns nil at end of file. The optional argument
     specifies the record separator. The separator is included with the
     contents of each record. A separator of nil reads the entire
     contents, and a zero-length separator reads the input one paragraph
     at a time, where paragraphs are divided by two consecutive
     newlines. If multiple filenames are present in ARGV, gets(nil) will
     read the contents one file at a time.
        ARGV << "testfile"
        print while gets
     produces:
        This is line one
        This is line two
        This is line three
        And so on...


$ ri Kernel#scan
----------------------------------------------------------- Kernel::scan
     scan( pattern ) -> anArray
     scan( pattern ) {| | block } -> $_
------------------------------------------------------------------------
     Equivalent to calling $_.scan. See String#scan on page 378.

$ ri Kernel#gsub
----------------------------------------------------------- Kernel::gsub
     gsub( pattern, replacement ) -> aString
     gsub( pattern ) {| | block }  -> aString
------------------------------------------------------------------------
     Equivalent to $_.gsub..., except that $_ receives the modified
     result.
        $_ =3D "quick brown fox"
        gsub /[aeiou]/, '*'   #=3D> "q**ck br*wn f*x"
        $_                    #=3D> "q**ck br*wn f*x"

--=20
Eric Hodel - drbrain@segment7.net - http://segment7.net
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