Re: This looks like someone sneezed and hit the keyboard

use YAPE::Regex::Explain;

$regex = qr/.*([\$#\%>~]|\@\w~\$|\\\[\\e\[0m\\\] \[0m)\s?/;

print YAPE::Regex::Explain->new($regex)->explain;
[download]

__OUTPUT__

The regular expression:

(?-imsx:.*([\$#%>~]|\@\w~\$|\\\[\\e\[0m\\\] \[0m)\s?)

matches as follows:

NODE                     EXPLANATION
----------------------------------------------------------------------
(?-imsx:                 group, but do not capture (case-sensitive)
                         (with ^ and $ matching normally) (with . not
                         matching \n) (matching whitespace and #
                         normally):
----------------------------------------------------------------------
  .*                       any character except \n (0 or more times
                           (matching the most amount possible))
----------------------------------------------------------------------
  (                        group and capture to \1:
----------------------------------------------------------------------
    [\$#%>~]                 any character of: '\$', '#', '%', '>',
                             '~'
----------------------------------------------------------------------
   |                        OR
----------------------------------------------------------------------
    \@                       '@'
----------------------------------------------------------------------
    \w                       word characters (a-z, A-Z, 0-9, _)
----------------------------------------------------------------------
    ~                        '~'
----------------------------------------------------------------------
    \$                       '$'
----------------------------------------------------------------------
   |                        OR
----------------------------------------------------------------------
    \\                       '\'
----------------------------------------------------------------------
    \[                       '['
----------------------------------------------------------------------
    \\                       '\'
----------------------------------------------------------------------
    e                        'e'
----------------------------------------------------------------------
    \[                       '['
----------------------------------------------------------------------
    0m                       '0m'
----------------------------------------------------------------------
    \\                       '\'
----------------------------------------------------------------------
    \]                       ']'
----------------------------------------------------------------------
                             ' '
----------------------------------------------------------------------
    \[                       '['
----------------------------------------------------------------------
    0m                       '0m'
----------------------------------------------------------------------
  )                        end of \1
----------------------------------------------------------------------
  \s?                      whitespace (\n, \r, \t, \f, and " ")
                           (optional (matching the most amount
                           possible))
----------------------------------------------------------------------
)                        end of grouping
----------------------------------------------------------------------
[download]

Let me show you my (colourful) command prompt... :-) which looks like: ($hostname)$fullpath>

export PS1="\[\033[1;37m\](\[\033[1;32m\]`uname -n`\[\033[1;37m\])\[\0
+33[1;36m\]\$PWD\[\033[1;37m\]>\[\033[0m\] "

# ANSI colour commands
#   \[\033[1;37m\]  => set colour to white (37)
#   \[\033[1;32m\]  => set colour to green (32)
#   \[\033[1;36m\]  => set colour to cyan  (36)
#   ...
#   \[\033[0m\]     => set colour back to normal
[download]

Comment on Re: This looks like someone sneezed and hit the keyboard Select or Download Code

Replies are listed 'Best First'.
Re: Re: This looks like someone sneezed and hit the keyboard by flyingmoose (Priest) on Feb 03, 2004 at 14:09 UTC
In one of my first projects using Perl (I had an internship at the time), someone wanted me to parse the output of top and another Unix tool. Both used ANSI codes, so I backed away. It looks like this guy didn't back away, so I'll give him a gold star for bravery. However, he looses his gold star for not commenting his code and using an ugly regex without the /x modifier. It's really amazing how many people (and in good open-source programs, too) forget to add line comments here at there when they could greatly help. I am not asking for flower-box style comments, just an occasional "now we parse the ANSI terminal prompt" kind of comment here and there. Long story short, people who never comment their code and modules implementations need to be shot :)	[reply]
Re: Re: Re: This looks like someone sneezed and hit the keyboard by ysth (Canon) on Feb 03, 2004 at 17:05 UTC
I have real trouble with remembering to use whitespace, comments, and /x in my regexs. I just don't have the habit (yet!) while writing code. Almost all the /x's that end up in my code are added after-the-fact. I'm almost ready to decide just to put an /x on all regexes (to help develop the habit), but I know that will get me strange looks.	[reply]
Re: Re: Re: Re: This looks like someone sneezed and hit the keyboard by flyingmoose (Priest) on Feb 03, 2004 at 19:27 UTC
My regexes tend to be very basic, so, like you I don't use /x much. It would look crazy if used everywhere. However, this example is pretty ugly and needs it just for maintaince purposes. We are lucky some folks remember what ANSI escape sequences look like, as someone who didn't use ANSI codes wouldn't have a clue.	[reply]
Re: Re: This looks like someone sneezed and hit the keyboard by spartan (Pilgrim) on Feb 03, 2004 at 17:31 UTC
wow. I'd spend all my votes to upvote this for a week if I could. I've always thought of regexes as a sort of black art (and still do to a certain degree), and I've always wanted something that would just explain in plain english what the heck a regex means when you read it. This could be my ticket (and possibly MANY others as well) to finally get a grip on regexes. Very funny Scotty... Now PLEASE beam down my PANTS!	[reply]
Re: Re: Re: This looks like someone sneezed and hit the keyboard by hessef (Monk) on Feb 03, 2004 at 18:01 UTC
Have you considered reading the O'Reilly Press book "Mastering Regular Expressions" by Jeffrey E. F. Friedl? The first few chapters explain in detail how to read regexes, step by step.	[reply]
Re:This looks like someone sneezed and hit the keyboard by Anonymous Monk on Feb 05, 2004 at 09:00 UTC
Hi, There is an article on perl.com that might be useful: http://www.perl.com/pub/a/2004/01/16/regexps.html Regexes are a programs. It takes time to learn new languages and that's why it might look difficult at the begining. With time and practice that kind of regex become (almost) clear. Using /x and commenting is very important but having the right support from the tools you use is also important. Here is a little html document that show your regex colored. I couldn't get it to show directly in this answer so you'll have to copy past :-(: <HTML> <HEAD> <TITLE>Smed generated dump</TITLE> </head> <body bgcolor="#FFFFFF"> <FONT color=#000000 style="BACKGROUND-COLOR: #ffffff"> <br> </FONT> <FONT color=#000000 style="BACKGROUND-COLOR: #ffffff"> <br> </FONT> <FONT color=#f00000 style="BACKGROUND-COLOR: #ffffff"> / </FONT> <FONT color=#ffff00 style="BACKGROUND-COLOR: #ff0000"> .* </FONT> <FONT color=#ffffff style="BACKGROUND-COLOR: #ff0000"> ( </FONT> <FONT color=#ffff00 style="BACKGROUND-COLOR: #643296"> [\$#\%>~] < +/FONT> <FONT color=#000000 style="BACKGROUND-COLOR: #00ff00"> \| </FONT> <FONT color=#ff0000 style="BACKGROUND-COLOR: #ffff00"> \@ </FONT> <FONT color=#000000 style="BACKGROUND-COLOR: #afeeee"> \w </FONT> <FONT color=#000000 style="BACKGROUND-COLOR: #f0f0ff"> ~ </FONT> <FONT color=#ff0000 style="BACKGROUND-COLOR: #ffff00"> \$ </FONT> <FONT color=#000000 style="BACKGROUND-COLOR: #00ff00"> \| </FONT> <FONT color=#ff0000 style="BACKGROUND-COLOR: #ffff00"> \\ </FONT> <FONT color=#ff0000 style="BACKGROUND-COLOR: #ffff00"> \[ </FONT> <FONT color=#ff0000 style="BACKGROUND-COLOR: #ffff00"> \\ </FONT> <FONT color=#000000 style="BACKGROUND-COLOR: #f0f0ff"> e </FONT> <FONT color=#ff0000 style="BACKGROUND-COLOR: #ffff00"> \[ </FONT> <FONT color=#000000 style="BACKGROUND-COLOR: #f0f0ff"> 0 </FONT> <FONT color=#000000 style="BACKGROUND-COLOR: #f0f0ff"> m </FONT> <FONT color=#ff0000 style="BACKGROUND-COLOR: #ffff00"> \\ </FONT> <FONT color=#ff0000 style="BACKGROUND-COLOR: #ffff00"> \] </FONT> <FONT color=#000000 style="BACKGROUND-COLOR: #f0f0ff"> </FONT> <FONT color=#ff0000 style="BACKGROUND-COLOR: #ffff00"> \[ </FONT> <FONT color=#000000 style="BACKGROUND-COLOR: #f0f0ff"> 0 </FONT> <FONT color=#000000 style="BACKGROUND-COLOR: #f0f0ff"> m </FONT> <FONT color=#ffffff style="BACKGROUND-COLOR: #ff0000"> ) </FONT> <FONT color=#000000 style="BACKGROUND-COLOR: #afeeee"> \s </FONT> <FONT color=#f00000 style="BACKGROUND-COLOR: #f0f0ff"> ? </FONT> <FONT color=#f00000 style="BACKGROUND-COLOR: #ffffff"> / </FONT> <FONT color=#000000 style="BACKGROUND-COLOR: #ffffff"> <br> </FONT> <FONT color=#000000 style="BACKGROUND-COLOR: #ffffff"> <br> </FONT> </body> </HTML> [download] If your text editor supported this, you would have less problems getting in regexes. There few tools to work on regexes and they do the coloring as well. Cheers, Nadim (NKH).	[reply] [d/l]
Re: Re: This looks like someone sneezed and hit the keyboard by Anonymous Monk on Feb 09, 2004 at 23:39 UTC
my (colourful) command prompt... :-) Or, simpler, with \h instead of `uname -n`: `export PS1="\[\033[1;37m\](\[\033[1;32m\]\u@\h\[\033[1;37m\])\[\033[1; +36m\]\$PWD\[\033[1;37m\]>\[\033[0m\] "` [download] which shows (username@host)path>	[reply] [d/l]


laziness, impatience, and hubris
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