[xclite]

Just a simple challenge to get back in the swing of things - life has been crazy. Of course, if my excuse is always that "life is crazy," I should just deal with it and call that "normal."

Right, the challenge.
In the fewest characters possible, implement grep. This version of grep is called as follows:

grep.rb regexp [File(s)]

If no files are present, the script should read from stdin. No requirements to support the various switches/flags, just that the script outputs lines matching the regexp.

Support Ruby regular expressions, rather than grep.

Restrictions:
1) No system calls of any kind
2) You shouldn't have to "require" or "load" anything
3) The results should be printed to STDOUT, one line of output per matching string.

This post has been edited by xclite: 03 October 2012 - 07:12 AM

[sepp2k]

Should the supported regex syntax be that of Ruby regexen or the one supported by grep?

Also: are there any restrictions on built-in methods that can be used?

This post has been edited by sepp2k: 03 October 2012 - 07:09 AM

[xclite]

Built-in methods are allowed, and I'm aware there are a few that will make this quite simple.

And I was going to mention which version but I totally forgot to include it: just use it as a Ruby REGEX instead of supporting grep.

[sepp2k]

Okay, here's my solution - 25 characters:

Spoiler

puts$<.grep /#{$*.shift}/

[Lemur]

sepp2k, on 03 October 2012 - 09:19 AM, said:

Okay, here's my solution - 25 characters:

Spoiler

puts$<.grep /#{$*.shift}/

Can't get much shorter than that one.

[NotarySojac]

In ruby, what does dollar sign less than symbol mean? I got most of that solusion, but that first symbol is evading google.

Here's an expanded solution that makes the algo slightly less cryptic, to anyone else who got a little lost:

Spoiler

#!/usr/bin/env ruby

file_arguments = $<  # aka ARGF

command_line_arguments = $*


puts file_arguments.grep /#{command_line_arguments.shift}/

This post has been edited by NotarySojac: 03 October 2012 - 06:41 PM

[blackcompe]

Quote

Okay, here's my solution - 25 characters:

Very Impressive.

Quote

In ruby, what does dollar sign less than symbol mean? I got most of that solusion, but that first symbol is evading google.

No need for him to explain it again.

Here's mine: 149 characters.

Spoiler

if ARGV.length == 1:puts $stdin.readlines.select{|l|l.match(ARGV[0])}
else ARGV[1..-1].map{|f|puts File.readlines(f).select{|l|l.match(ARGV[0])}} end

I need to DRY that out.

This post has been edited by blackcompe: 03 October 2012 - 06:36 PM