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Perl-Users Digest, Issue: 2790 Volume: 11

daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Tue Jan 26 14:09:46 2010

Date: Tue, 26 Jan 2010 11:09:27 -0800 (PST)
From: Perl-Users Digest <Perl-Users-Request@ruby.OCE.ORST.EDU>
To: Perl-Users@ruby.OCE.ORST.EDU (Perl-Users Digest)

Perl-Users Digest           Tue, 26 Jan 2010     Volume: 11 Number: 2790

Today's topics:
    Re: Leanest way to get at keyboard events ? <peter@www.pjb.com.au>
        Posting Guidelines for comp.lang.perl.misc ($Revision:  tadmc@seesig.invalid
    Re: print array with separator? <rvtol+usenet@xs4all.nl>
    Re: print array with separator? <hjp-usenet2@hjp.at>
    Re: print array with separator? <jurgenex@hotmail.com>
    Re: print array with separator? <hjp-usenet2@hjp.at>
    Re: print array with separator? <rvtol+usenet@xs4all.nl>
    Re: print array with separator? <john@castleamber.com>
    Re: What are the minimum and maximum float numbers and  sln@netherlands.com
    Re: When to use "use strict;"? <OJZGSRPBZVCX@spammotel.com>
    Re: When to use "use strict;"? <RedGrittyBrick@spamweary.invalid>
    Re: When to use "use strict;"? <cwilbur@chromatico.net>
        Digest Administrivia (Last modified: 6 Apr 01) (Perl-Users-Digest Admin)

----------------------------------------------------------------------

Date: 26 Jan 2010 06:02:14 GMT
From: Peter Billam <peter@www.pjb.com.au>
Subject: Re: Leanest way to get at keyboard events ?
Message-Id: <slrnhlt1b7.3kp.peter@box8.pjb.com.au>

On 2010-01-22, Alan Curry <pacman@kosh.dhis.org> wrote:
> In article <slrnhlhubu.3mc.peter@box8.pjb.com.au>,
> Peter Billam  <contact.html@www.pjb.com.au> wrote:
>>In a small command-line app, e.g. running in an xterm or a
>>linux console, I need to get at the keydown and keyup events.
>
> On a VC (i.e. /dev/tty1 through /dev/tty63) you can put the keyboard
> into raw (scancode) or medium-raw (keycode) mode with the KDSKBMODE
> ioctl. Seeconsole_ioctl(4). It shouldn't take much to make that
> work from perl. ... The xterm case will probably be harder.

It didn't take long to give up the idea of kbd-event-handling from
the command-line :-) I thought about doing it as CGI/JavaScript,
but ended up just making it a _monophonic_ keyboard and reading
bytes from STDIN.  Now in its first production version ...
  http://www.pjb.com.au/midi/index.html
  http://www.pjb.com.au/midi/midikbd.html

Thanks for help,   Regards,  Peter

-- 
Peter Billam       www.pjb.com.au    www.pjb.com.au/comp/contact.html


------------------------------

Date: Tue, 26 Jan 2010 02:13:29 -0600
From: tadmc@seesig.invalid
Subject: Posting Guidelines for comp.lang.perl.misc ($Revision: 1.9 $)
Message-Id: <0YydnZQzk8K0OcPWnZ2dnUVZ_rqdnZ2d@giganews.com>

Outline
   Before posting to comp.lang.perl.misc
      Must
       - Check the Perl Frequently Asked Questions (FAQ)
       - Check the other standard Perl docs (*.pod)
      Really Really Should
       - Lurk for a while before posting
       - Search a Usenet archive
      If You Like
       - Check Other Resources
   Posting to comp.lang.perl.misc
      Is there a better place to ask your question?
       - Question should be about Perl, not about the application area
      How to participate (post) in the clpmisc community
       - Carefully choose the contents of your Subject header
       - Use an effective followup style
       - Speak Perl rather than English, when possible
       - Ask perl to help you
       - Do not re-type Perl code
       - Provide enough information
       - Do not provide too much information
       - Do not post binaries, HTML, or MIME
      Social faux pas to avoid
       - Asking a Frequently Asked Question
       - Asking a question easily answered by a cursory doc search
       - Asking for emailed answers
       - Beware of saying "doesn't work"
       - Sending a "stealth" Cc copy
      Be extra cautious when you get upset
       - Count to ten before composing a followup when you are upset
       - Count to ten after composing and before posting when you are upset
-----------------------------------------------------------------

Posting Guidelines for comp.lang.perl.misc ($Revision: 1.9 $)
    This newsgroup, commonly called clpmisc, is a technical newsgroup
    intended to be used for discussion of Perl related issues (except job
    postings), whether it be comments or questions.

    As you would expect, clpmisc discussions are usually very technical in
    nature and there are conventions for conduct in technical newsgroups
    going somewhat beyond those in non-technical newsgroups.

    The article at:

        http://www.catb.org/~esr/faqs/smart-questions.html

    describes how to get answers from technical people in general.

    This article describes things that you should, and should not, do to
    increase your chances of getting an answer to your Perl question. It is
    available in POD, HTML and plain text formats at:

     http://www.rehabitation.com/clpmisc.shtml

    For more information about netiquette in general, see the "Netiquette
    Guidelines" at:

     http://andrew2.andrew.cmu.edu/rfc/rfc1855.html

    A note to newsgroup "regulars":

       Do not use these guidelines as a "license to flame" or other
       meanness. It is possible that a poster is unaware of things
       discussed here.  Give them the benefit of the doubt, and just
       help them learn how to post, rather than assume that they do 
       know and are being the "bad kind" of Lazy.

    A note about technical terms used here:

       In this document, we use words like "must" and "should" as
       they're used in technical conversation (such as you will
       encounter in this newsgroup). When we say that you *must* do
       something, we mean that if you don't do that something, then
       it's unlikely that you will benefit much from this group.
       We're not bossing you around; we're making the point without
       lots of words.

    Do *NOT* send email to the maintainer of these guidelines. It will be
    discarded unread. The guidelines belong to the newsgroup so all
    discussion should appear in the newsgroup. I am just the secretary that
    writes down the consensus of the group.

Before posting to comp.lang.perl.misc
  Must
    This section describes things that you *must* do before posting to
    clpmisc, in order to maximize your chances of getting meaningful replies
    to your inquiry and to avoid getting flamed for being lazy and trying to
    have others do your work.

    The perl distribution includes documentation that is copied to your hard
    drive when you install perl. Also installed is a program for looking
    things up in that (and other) documentation named 'perldoc'.

    You should either find out where the docs got installed on your system,
    or use perldoc to find them for you. Type "perldoc perldoc" to learn how
    to use perldoc itself. Type "perldoc perl" to start reading Perl's
    standard documentation.

    Check the Perl Frequently Asked Questions (FAQ)
        Checking the FAQ before posting is required in Big 8 newsgroups in
        general, there is nothing clpmisc-specific about this requirement.
        You are expected to do this in nearly all newsgroups.

        You can use the "-q" switch with perldoc to do a word search of the
        questions in the Perl FAQs.

    Check the other standard Perl docs (*.pod)
        The perl distribution comes with much more documentation than is
        available for most other newsgroups, so in clpmisc you should also
        see if you can find an answer in the other (non-FAQ) standard docs
        before posting.

    It is *not* required, or even expected, that you actually *read* all of
    Perl's standard docs, only that you spend a few minutes searching them
    before posting.

    Try doing a word-search in the standard docs for some words/phrases
    taken from your problem statement or from your very carefully worded
    "Subject:" header.

  Really Really Should
    This section describes things that you *really should* do before posting
    to clpmisc.

    Lurk for a while before posting
        This is very important and expected in all newsgroups. Lurking means
        to monitor a newsgroup for a period to become familiar with local
        customs. Each newsgroup has specific customs and rituals. Knowing
        these before you participate will help avoid embarrassing social
        situations. Consider yourself to be a foreigner at first!

    Search a Usenet archive
        There are tens of thousands of Perl programmers. It is very likely
        that your question has already been asked (and answered). See if you
        can find where it has already been answered.

        One such searchable archive is:

         http://groups.google.com/advanced_search

  If You Like
    This section describes things that you *can* do before posting to
    clpmisc.

    Check Other Resources
        You may want to check in books or on web sites to see if you can
        find the answer to your question.

        But you need to consider the source of such information: there are a
        lot of very poor Perl books and web sites, and several good ones
        too, of course.

Posting to comp.lang.perl.misc
    There can be 200 messages in clpmisc in a single day. Nobody is going to
    read every article. They must decide somehow which articles they are
    going to read, and which they will skip.

    Your post is in competition with 199 other posts. You need to "win"
    before a person who can help you will even read your question.

    These sections describe how you can help keep your article from being
    one of the "skipped" ones.

  Is there a better place to ask your question?
    Question should be about Perl, not about the application area
        It can be difficult to separate out where your problem really is,
        but you should make a conscious effort to post to the most
        applicable newsgroup. That is, after all, where you are the most
        likely to find the people who know how to answer your question.

        Being able to "partition" a problem is an essential skill for
        effectively troubleshooting programming problems. If you don't get
        that right, you end up looking for answers in the wrong places.

        It should be understood that you may not know that the root of your
        problem is not Perl-related (the two most frequent ones are CGI and
        Operating System related), so off-topic postings will happen from
        time to time. Be gracious when someone helps you find a better place
        to ask your question by pointing you to a more applicable newsgroup.

  How to participate (post) in the clpmisc community
    Carefully choose the contents of your Subject header
        You have 40 precious characters of Subject to win out and be one of
        the posts that gets read. Don't waste them. Take care while
        composing them, they are the key that opens the door to getting an
        answer.

        Spend them indicating what aspect of Perl others will find if they
        should decide to read your article.

        Do not spend them indicating "experience level" (guru, newbie...).

        Do not spend them pleading (please read, urgent, help!...).

        Do not spend them on non-Subjects (Perl question, one-word
        Subject...)

        For more information on choosing a Subject see "Choosing Good
        Subject Lines":

         http://www.cpan.org/authors/id/D/DM/DMR/subjects.post

        Part of the beauty of newsgroup dynamics, is that you can contribute
        to the community with your very first post! If your choice of
        Subject leads a fellow Perler to find the thread you are starting,
        then even asking a question helps us all.

    Use an effective followup style
        When composing a followup, quote only enough text to establish the
        context for the comments that you will add. Always indicate who
        wrote the quoted material. Never quote an entire article. Never
        quote a .signature (unless that is what you are commenting on).

        Intersperse your comments *following* each section of quoted text to
        which they relate. Unappreciated followup styles are referred to as
        "top-posting", "Jeopardy" (because the answer comes before the
        question), or "TOFU" (Text Over, Fullquote Under).

        Reversing the chronology of the dialog makes it much harder to
        understand (some folks won't even read it if written in that style).
        For more information on quoting style, see:

         http://web.presby.edu/~nnqadmin/nnq/nquote.html

    Speak Perl rather than English, when possible
        Perl is much more precise than natural language. Saying it in Perl
        instead will avoid misunderstanding your question or problem.

        Do not say: I have variable with "foo\tbar" in it.

        Instead say: I have $var = "foo\tbar", or I have $var = 'foo\tbar',
        or I have $var = <DATA> (and show the data line).

    Ask perl to help you
        You can ask perl itself to help you find common programming mistakes
        by doing two things: enable warnings (perldoc warnings) and enable
        "strict"ures (perldoc strict).

        You should not bother the hundreds/thousands of readers of the
        newsgroup without first seeing if a machine can help you find your
        problem. It is demeaning to be asked to do the work of a machine. It
        will annoy the readers of your article.

        You can look up any of the messages that perl might issue to find
        out what the message means and how to resolve the potential mistake
        (perldoc perldiag). If you would like perl to look them up for you,
        you can put "use diagnostics;" near the top of your program.

    Do not re-type Perl code
        Use copy/paste or your editor's "import" function rather than
        attempting to type in your code. If you make a typo you will get
        followups about your typos instead of about the question you are
        trying to get answered.

    Provide enough information
        If you do the things in this item, you will have an Extremely Good
        chance of getting people to try and help you with your problem!
        These features are a really big bonus toward your question winning
        out over all of the other posts that you are competing with.

        First make a short (less than 20-30 lines) and *complete* program
        that illustrates the problem you are having. People should be able
        to run your program by copy/pasting the code from your article. (You
        will find that doing this step very often reveals your problem
        directly. Leading to an answer much more quickly and reliably than
        posting to Usenet.)

        Describe *precisely* the input to your program. Also provide example
        input data for your program. If you need to show file input, use the
        __DATA__ token (perldata.pod) to provide the file contents inside of
        your Perl program.

        Show the output (including the verbatim text of any messages) of
        your program.

        Describe how you want the output to be different from what you are
        getting.

        If you have no idea at all of how to code up your situation, be sure
        to at least describe the 2 things that you *do* know: input and
        desired output.

    Do not provide too much information
        Do not just post your entire program for debugging. Most especially
        do not post someone *else's* entire program.

    Do not post binaries, HTML, or MIME
        clpmisc is a text only newsgroup. If you have images or binaries
        that explain your question, put them in a publically accessible
        place (like a Web server) and provide a pointer to that location. If
        you include code, cut and paste it directly in the message body.
        Don't attach anything to the message. Don't post vcards or HTML.
        Many people (and even some Usenet servers) will automatically filter
        out such messages. Many people will not be able to easily read your
        post. Plain text is something everyone can read.

  Social faux pas to avoid
    The first two below are symptoms of lots of FAQ asking here in clpmisc.
    It happens so often that folks will assume that it is happening yet
    again. If you have looked but not found, or found but didn't understand
    the docs, say so in your article.

    Asking a Frequently Asked Question
        It should be understood that you may have missed the applicable FAQ
        when you checked, which is not a big deal. But if the Frequently
        Asked Question is worded similar to your question, folks will assume
        that you did not look at all. Don't become indignant at pointers to
        the FAQ, particularly if it solves your problem.

    Asking a question easily answered by a cursory doc search
        If folks think you have not even tried the obvious step of reading
        the docs applicable to your problem, they are likely to become
        annoyed.

        If you are flamed for not checking when you *did* check, then just
        shrug it off (and take the answer that you got).

    Asking for emailed answers
        Emailed answers benefit one person. Posted answers benefit the
        entire community. If folks can take the time to answer your
        question, then you can take the time to go get the answer in the
        same place where you asked the question.

        It is OK to ask for a *copy* of the answer to be emailed, but many
        will ignore such requests anyway. If you munge your address, you
        should never expect (or ask) to get email in response to a Usenet
        post.

        Ask the question here, get the answer here (maybe).

    Beware of saying "doesn't work"
        This is a "red flag" phrase. If you find yourself writing that,
        pause and see if you can't describe what is not working without
        saying "doesn't work". That is, describe how it is not what you
        want.

    Sending a "stealth" Cc copy
        A "stealth Cc" is when you both email and post a reply without
        indicating *in the body* that you are doing so.

  Be extra cautious when you get upset
    Count to ten before composing a followup when you are upset
        This is recommended in all Usenet newsgroups. Here in clpmisc, most
        flaming sub-threads are not about any feature of Perl at all! They
        are most often for what was seen as a breach of netiquette. If you
        have lurked for a bit, then you will know what is expected and won't
        make such posts in the first place.

        But if you get upset, wait a while before writing your followup. I
        recommend waiting at least 30 minutes.

    Count to ten after composing and before posting when you are upset
        After you have written your followup, wait *another* 30 minutes
        before committing yourself by posting it. You cannot take it back
        once it has been said.

AUTHOR
    Tad McClellan and many others on the comp.lang.perl.misc newsgroup.

-- 
Tad McClellan
email: perl -le "print scalar reverse qq/moc.liamg\100cm.j.dat/"


------------------------------

Date: Tue, 26 Jan 2010 10:38:16 +0100
From: "Dr.Ruud" <rvtol+usenet@xs4all.nl>
Subject: Re: print array with separator?
Message-Id: <4b5eb808$0$22918$e4fe514c@news.xs4all.nl>

Peng Yu wrote:

> @array=("a", "b", "c");

1. "array" is the stupidest name for an array.
2. whitespace is cheap
0. use strict; use warnings;

   my @word = qw/ a b c /;

   my @word = "a" .. "c";

-- 
Ruud


------------------------------

Date: Tue, 26 Jan 2010 11:44:54 +0100
From: "Peter J. Holzer" <hjp-usenet2@hjp.at>
Subject: Re: print array with separator?
Message-Id: <slrnhltht7.o54.hjp-usenet2@hrunkner.hjp.at>

On 2010-01-26 09:38, Dr.Ruud <rvtol+usenet@xs4all.nl> wrote:
> Peng Yu wrote:
>> @array=("a", "b", "c");
>
> 1. "array" is the stupidest name for an array.
[...]
>    my @word = qw/ a b c /;

The name of a variable should tell the reader something about its
content and/or purpose. So I would agree that @array is in almost all
cases a very stupid name, as it doesn't tell you anything except that
it's an array, and it does so redundantly ("@" and "array").

However, in this example, the only thing important is that is an array.
It isn't important what kind of data is in the array (except that the
elements are strings or can be stringified) or what the data is used
for. So @array is ok, because it tells you that this is "just an array".

@word, however, is a bad name. It conveys that the array contains
"words". This then causes the reader to wonder what a "word" is (an
English word? No, "b" and "c" are not English words. Some other natural
language? Maybe. Strings matching /^\w+$/? Maybe.) and whether the
example is still valid if an element contains data which is not a
"word".

So @stringifiable_data might be ideal but it's a bit long. @strings is
already a bit too narrow (is 1 a string? Is an object with an
overloaded "" operator a string?), in about the same sense that @array
is too wide. So I don't really see that one of @stringifiable_data,
@strings or @array is clearly better than the others.

	hp



------------------------------

Date: Tue, 26 Jan 2010 08:39:43 -0800
From: Jürgen Exner <jurgenex@hotmail.com>
Subject: Re: print array with separator?
Message-Id: <qf6ul5ppld7ilesndl0cifvnu8avhsoubu@4ax.com>

"Peter J. Holzer" <hjp-usenet2@hjp.at> wrote:
>On 2010-01-26 09:38, Dr.Ruud <rvtol+usenet@xs4all.nl> wrote:
>> Peng Yu wrote:
>>> @array=("a", "b", "c");
>>
>> 1. "array" is the stupidest name for an array.
>[...]
>>    my @word = qw/ a b c /;
>
>The name of a variable should tell the reader something about its
>content and/or purpose. So I would agree that @array is in almost all
>cases a very stupid name, as it doesn't tell you anything except that
>it's an array, and it does so redundantly ("@" and "array").
>
>However, in this example, the only thing important is that is an array.
>It isn't important what kind of data is in the array (except that the
>elements are strings or can be stringified) or what the data is used
>for. So @array is ok, because it tells you that this is "just an array".

Ack

>@word, however, is a bad name. It conveys that the array contains
>"words". 

Actually it conveys that @word contains exactly one word, maybe split
into individual letters. 

>This then causes the reader to wonder what a "word" is (an
>English word? No, "b" and "c" are not English words. Some other natural
>language? Maybe. Strings matching /^\w+$/? Maybe.) and whether the
>example is still valid if an element contains data which is not a
>"word".

If that would have been the intented meaning then @words would have been
preferable to @word.

jue


------------------------------

Date: Tue, 26 Jan 2010 18:11:20 +0100
From: "Peter J. Holzer" <hjp-usenet2@hjp.at>
Subject: Re: print array with separator?
Message-Id: <slrnhlu8hp.dek.hjp-usenet2@hrunkner.hjp.at>

On 2010-01-26 16:39, Jürgen Exner <jurgenex@hotmail.com> wrote:
> "Peter J. Holzer" <hjp-usenet2@hjp.at> wrote:
>>On 2010-01-26 09:38, Dr.Ruud <rvtol+usenet@xs4all.nl> wrote:
>>> Peng Yu wrote:
>>>> @array=("a", "b", "c");
>>>
>>> 1. "array" is the stupidest name for an array.
>>[...]
>>>    my @word = qw/ a b c /;
>>
>>The name of a variable should tell the reader something about its
>>content and/or purpose. So I would agree that @array is in almost all
>>cases a very stupid name, as it doesn't tell you anything except that
>>it's an array, and it does so redundantly ("@" and "array").
>>
>>However, in this example, the only thing important is that is an array.
>>It isn't important what kind of data is in the array (except that the
>>elements are strings or can be stringified) or what the data is used
>>for. So @array is ok, because it tells you that this is "just an array".
>
> Ack
>
>>@word, however, is a bad name. It conveys that the array contains
>>"words". 
>
> Actually it conveys that @word contains exactly one word, maybe split
> into individual letters. 
[...]
> If that would have been the intented meaning then @words would have been
> preferable to @word.

I, too, prefer using the plural for array names.

But there are valid arguments for using the singular:

 * $word[5] reads more naturally as "word (number) 5" than $words[5].

 * In Perl, singular/plural is expressed by the sigil, so
   @word is already "several word(s)" and the English plural-s is 
   at best redundant and at worst harmful, because Perl doesn't
   understand it (@words is *not* the array containing $word[0], 
   $word[1], ...).

So I consider that a matter of personal style and decided not to
complicate this discussion by bringing up the singular/plural debate.
I should have known that somebody else would ...

	hp



------------------------------

Date: Tue, 26 Jan 2010 19:21:01 +0100
From: "Dr.Ruud" <rvtol+usenet@xs4all.nl>
Subject: Re: print array with separator?
Message-Id: <4b5f328d$0$22917$e4fe514c@news.xs4all.nl>

Peter J. Holzer wrote:
> On 2010-01-26 16:39, Jürgen Exner <jurgenex@hotmail.com> wrote:
>> "Peter J. Holzer" <hjp-usenet2@hjp.at> wrote:
>>> On 2010-01-26 09:38, Dr.Ruud <rvtol+usenet@xs4all.nl> wrote:
>>>> Peng Yu wrote:

>>>>> @array=("a", "b", "c");
>>>> 1. "array" is the stupidest name for an array.
>>> [...]
>>>>    my @word = qw/ a b c /;
>>> The name of a variable should tell the reader something about its
>>> content and/or purpose. So I would agree that @array is in almost all
>>> cases a very stupid name, as it doesn't tell you anything except that
>>> it's an array, and it does so redundantly ("@" and "array").
>>>
>>> However, in this example, the only thing important is that is an array.
>>> It isn't important what kind of data is in the array (except that the
>>> elements are strings or can be stringified) or what the data is used
>>> for. So @array is ok, because it tells you that this is "just an array".
>> Ack
>>
>>> @word, however, is a bad name. It conveys that the array contains
>>> "words". 
>> Actually it conveys that @word contains exactly one word, maybe split
>> into individual letters. 
> [...]
>> If that would have been the intented meaning then @words would have been
>> preferable to @word.
> 
> I, too, prefer using the plural for array names.
> 
> But there are valid arguments for using the singular:
> 
>  * $word[5] reads more naturally as "word (number) 5" than $words[5].
> 
>  * In Perl, singular/plural is expressed by the sigil, so
>    @word is already "several word(s)" and the English plural-s is 
>    at best redundant and at worst harmful, because Perl doesn't
>    understand it (@words is *not* the array containing $word[0], 
>    $word[1], ...).
> 
> So I consider that a matter of personal style and decided not to
> complicate this discussion by bringing up the singular/plural debate.
> I should have known that somebody else would ...

When calling it @word, I hoped for these comments.
:)

-- 
Ruud


------------------------------

Date: Tue, 26 Jan 2010 12:29:19 -0600
From: John Bokma <john@castleamber.com>
Subject: Re: print array with separator?
Message-Id: <87bpggk9ds.fsf@castleamber.com>

"Uri Guttman" <uri@StemSystems.com> writes:

>>>>>> "JB" == John Bokma <john@castleamber.com> writes:
>
>   JB> I wouldn't use it though, but like Abigail, IIRC, once wrote, there is
>   JB> no reason to have a problem with map in void context because we use
>   JB> other functions in void context without problems (like print).
>
> the point with map in void context is not efficiency

It used to be, and back then, IMO there was a much stronger argument to
not use map in void context.

> but in conveying
> meaning to the reader. map is intended to generate a list, not execute
> side effects.

But who decides that map is not intended for its side effects? In Perl
there are IMO quite some constructs that are used in somewhat unexpected
ways, especially to people new to the language.

> for modifier does the same thing and is meant for side
> effects as it doesn't generate a list. perl has many related things like
> this and you should choose the one with better semantics for your
> intentions. map generates lists so use it that way. for modifier doesn't
> generate lists so use it for side effects.

Like I wrote, I don't like it, and won't use it. But the arguments
against using map in void context are more a matter of taste IMO. The
"its not intended for that" is weak at best, in my (current) opinion.

-- 
John Bokma                                                               j3b

Hacking & Hiking in Mexico -  http://johnbokma.com/
http://castleamber.com/ - Perl & Python Development


------------------------------

Date: Tue, 26 Jan 2010 09:52:26 -0800
From: sln@netherlands.com
Subject: Re: What are the minimum and maximum float numbers and integers?
Message-Id: <6paul5p1288p40puinvl5p9s2fg42htdvo@4ax.com>

On Mon, 25 Jan 2010 13:19:32 -0800 (PST), Peng Yu <pengyu.ut@gmail.com> wrote:

>Is there a way to get the minimum and maximum float numbers and
>integers?

Something like this should get you in the range.

-sln

---------------
use strict;
use warnings;

my $exp = 10;
while (sprintf("%e", 10**$exp) !~ /inf/i) {
	++$exp;
}
--$exp;

my $places = 6;
my $mant   = 2 - .1;   # Because 2 always overflows

while (sprintf("%e", $mant * 10**$exp) =~ /inf/i) {
	$mant /= 1 + 10**(-$places);
}

printf ("UINT:   %u\n", -1);
printf ("INT:    +/- %d\n", sprintf ("%u", -1) / 2);
printf ("FLOAT:  +/- %.".$places."e\n", $mant * 10**$exp);

__END__

UINT:   4294967295
INT:    +/- 2147483647
FLOAT:  +/- 1.797693e+308



------------------------------

Date: Tue, 26 Jan 2010 08:38:14 +0100
From: "Jochen Lehmeier" <OJZGSRPBZVCX@spammotel.com>
Subject: Re: When to use "use strict;"?
Message-Id: <op.u64p50wtmk9oye@frodo>

On Tue, 26 Jan 2010 00:34:46 +0100, Peng Yu <pengyu.ut@gmail.com> wrote:

> Do I still need to add "use strict" to my perl program?

Yes.


------------------------------

Date: Tue, 26 Jan 2010 14:09:28 +0000
From: RedGrittyBrick <RedGrittyBrick@spamweary.invalid>
Subject: Re: When to use "use strict;"?
Message-Id: <4b5ef798$0$2540$da0feed9@news.zen.co.uk>


Peng Yu wrote:
> I was told to always use "use strict;" in another thread in this
> newsgroup. However, I checked Programming Perl. It seems that "use
> strict" is not necessary for small program.
> 
> In my case, each my perl script is less than 100 lines and would be
> reused anywhere else. Do I still need to add "use strict" to my perl
> program?

I always use strict (except in one-liners).

-- 
RGB


------------------------------

Date: Tue, 26 Jan 2010 11:23:54 -0500
From: Charlton Wilbur <cwilbur@chromatico.net>
Subject: Re: When to use "use strict;"?
Message-Id: <867hr4al7p.fsf@mithril.chromatico.net>

>>>>> "PY" == Peng Yu <pengyu.ut@gmail.com> writes:

    PY> I was told to always use "use strict;" in another thread in this
    PY> newsgroup. However, I checked Programming Perl. It seems that
    PY> "use strict" is not necessary for small program.

If you need to ask, you aren't experienced enough to know when you don't
need it.  And if you are experienced enough to know when you don't need
it, you've also been bitten by stupid bugs often enough to always use it
anyway.


Charlton


-- 
Charlton Wilbur
cwilbur@chromatico.net


------------------------------

Date: 6 Apr 2001 21:33:47 GMT (Last modified)
From: Perl-Users-Request@ruby.oce.orst.edu (Perl-Users-Digest Admin) 
Subject: Digest Administrivia (Last modified: 6 Apr 01)
Message-Id: <null>


Administrivia:

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------------------------------
End of Perl-Users Digest V11 Issue 2790
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