Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.php > #2834 > unrolled thread

A Few Noob Questions

Back to article view | Back to comp.lang.php

Contents

  A Few Noob Questions "eBob.com" <eBob.com@totallybogus.com> - 2011-08-16 11:02 -0400
    Re: A Few Noob Questions A.Reader <anonymously@example.com> - 2011-08-16 11:11 -0400
      Re: A Few Noob Questions The Natural Philosopher <tnp@invalid.invalid> - 2011-08-16 16:35 +0100
    Re: A Few Noob Questions Tim Streater <timstreater@greenbee.net> - 2011-08-16 17:03 +0100
    Re: A Few Noob Questions Man-wai Chang <toylet.toylet@gmail.com> - 2011-08-17 00:35 +0800
      Re: A Few Noob Questions Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2011-08-16 19:24 +0200
        Re: A Few Noob Questions The Natural Philosopher <tnp@invalid.invalid> - 2011-08-16 23:58 +0100
          Re: A Few Noob Questions Man-wai Chang <toylet.toylet@gmail.com> - 2011-08-19 00:41 +0800
            Re: A Few Noob Questions The Natural Philosopher <tnp@invalid.invalid> - 2011-08-18 18:33 +0100
            Re: A Few Noob Questions Tim Streater <timstreater@greenbee.net> - 2011-08-18 18:39 +0100
              Re: A Few Noob Questions The Natural Philosopher <tnp@invalid.invalid> - 2011-08-18 19:09 +0100
        Re: A Few Noob Questions Man-wai Chang <toylet.toylet@gmail.com> - 2011-08-19 00:40 +0800
          Re: A Few Noob Questions The Natural Philosopher <tnp@invalid.invalid> - 2011-08-18 18:26 +0100
          Re: A Few Noob Questions A.Reader <anonymously@example.com> - 2011-08-18 13:44 -0400
          Re: A Few Noob Questions Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2011-08-20 19:48 +0200
            Re: A Few Noob Questions Samuel Smythe <s.smythe@yahoo.com> - 2011-08-20 15:08 -0400
              Re: A Few Noob Questions Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2011-08-20 23:31 +0200
                Re: A Few Noob Questions Samuel Smythe <s.smythe@yahoo.com> - 2011-08-20 18:37 -0400
                  Re: A Few Noob Questions Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2011-08-21 00:41 +0200
                    Re: A Few Noob Questions Samuel Smythe <s.smythe@yahoo.com> - 2011-08-20 19:04 -0400
                      Re: A Few Noob Questions Jerry Stuckle <jstucklex@attglobal.net> - 2011-08-20 21:44 -0400
                      Re: A Few Noob Questions Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2011-08-21 09:16 +0200
          Re: A Few Noob Questions Jerry Stuckle <jstucklex@attglobal.net> - 2011-08-20 15:52 -0400
    Re: A Few Noob Questions Denis McMahon <denis.m.f.mcmahon@gmail.com> - 2011-08-16 21:30 +0000
      Re: A Few Noob Questions "eBob.com" <eBob.com@totallybogus.com> - 2011-08-16 20:31 -0400
        Re: A Few Noob Questions A.Reader <anonymously@example.com> - 2011-08-17 05:50 -0400
          Re: A Few Noob Questions "eBob.com" <eBob.com@totallybogus.com> - 2011-08-18 10:12 -0400

Page 1 of 2  [1] 2  Next page →

#2834 — A Few Noob Questions

Is "script" official terminology in PHP?  The book I am reading says 
"Built-in superglobal variables are visible everywhere within a script." but 
has never explicitly defined "script".  (Although there is a hint that maybe 
everything between tags is a script.)

How can the "units" of PHP between tags communicate?  Can my PHP code create 
$GLOBALS variables?  How about $_SESSION variables?

The book gives the following example of a ternary operator:

($grade >= 50 ? 'Passed" : "Failed")

I don't understand the function of the enclosing parentheses.  The official 
doc at php.net doesn't seem to suggest that the parentheses are necessary.

Just to make sure, "@" only suppresses MESSAGES.  It does not interfere with 
try/catch logic/code.  Right?

Thanks very much.

Bob 

[toc] | [next] | [standalone]

#2836

On Tue, 16 Aug 2011 11:02:40 -0400,
"eBob.com" <eBob.com@totallybogus.com> wrote:

>Is "script" official terminology in PHP?  The book I am reading says 
>"Built-in superglobal variables are visible everywhere within a script." but 
>has never explicitly defined "script".  (Although there is a hint that maybe 
>everything between tags is a script.)

"Script" in this context is a synonym for "program".  Some people
seem to need to make things confusing by giving new names to old
concepts.

>
>How can the "units" of PHP between tags communicate?  Can my PHP code create 
>$GLOBALS variables?  How about $_SESSION variables?

You'll have to ask the question in a different way.

>
>The book gives the following example of a ternary operator:
>
>($grade >= 50 ? 'Passed" : "Failed")
>
>I don't understand the function of the enclosing parentheses.  The official 
>doc at php.net doesn't seem to suggest that the parentheses are necessary.

The parens encapsulate the expression/statement, and prevent the
compiler from getting confused.  You'll see similar uses in other
contexts.

>
>Just to make sure, "@" only suppresses MESSAGES.  It does not interfere with 
>try/catch logic/code.  Right?

Right. 

[toc] | [prev] | [next] | [standalone]

#2837

A.Reader wrote:
> On Tue, 16 Aug 2011 11:02:40 -0400,
> "eBob.com" <eBob.com@totallybogus.com> wrote:
> 
>> Is "script" official terminology in PHP?  The book I am reading says 
>> "Built-in superglobal variables are visible everywhere within a script." but 
>> has never explicitly defined "script".  (Although there is a hint that maybe 
>> everything between tags is a script.)
> 
> "Script" in this context is a synonym for "program".  Some people
> seem to need to make things confusing by giving new names to old
> concepts.
> 
Script tends to be or interpreted code, rather than compiled.

[toc] | [prev] | [next] | [standalone]

#2839

In article <3Ev2q.149930$AU4.73655@en-nntp-07.dc1.easynews.com>,
 "eBob.com" <eBob.com@totallybogus.com> wrote:

> Is "script" official terminology in PHP?  The book I am reading says 
> "Built-in superglobal variables are visible everywhere within a script." but 
> has never explicitly defined "script".  (Although there is a hint that maybe 
> everything between tags is a script.)
> 
> How can the "units" of PHP between tags communicate?  Can my PHP code create 
> $GLOBALS variables?  How about $_SESSION variables?

Are you talking about a file that might contain a number of <?php ?> tag 
pairs?

> The book gives the following example of a ternary operator:
> 
> ($grade >= 50 ? 'Passed" : "Failed")
> 
> I don't understand the function of the enclosing parentheses.  The official 
> doc at php.net doesn't seem to suggest that the parentheses are necessary.

I can't remember if this is actually the case but it probably has to do 
with operator precedence. If you put parens around it then you know it 
will be executed as a unit. Otherwise you may find that when you combine 
it with other expressions execution does not proceed as you expect. It 
may also make things clearer to you the reader, even if strictly they 
are not necessary.

> Just to make sure, "@" only suppresses MESSAGES.  It does not interfere with 
> try/catch logic/code.  Right?

Right.

-- 
Tim

"That excessive bail ought not to be required, nor excessive fines imposed,
nor cruel and unusual punishments inflicted"  --  Bill of Rights 1689

[toc] | [prev] | [next] | [standalone]

#2840

On 16/08/11 11:02 PM, eBob.com wrote:
> Is "script" official terminology in PHP? The book I am reading says
> "Built-in superglobal variables are visible everywhere within a script."
> but has never explicitly defined "script". (Although there is a hint
> that maybe everything between tags is a script.)

In the old days, "Programs" were compiled into binary codes for direct 
execution by the CPU. "Scripts" were not compiled, but interpreted by a 
program called intepreter.

-- 
   @~@   You have the right to remain silent.
  / v \  Simplicity is Beauty!
/( _ )\ May the Force and farces be with you!
   ^ ^   (x86_64 Ubuntu 9.10)  Linux 2.6.39.3
不借貸! 不詐騙! 不援交! 不打交! 不打劫! 不自殺! 請考慮綜援 (CSSA):
http://www.swd.gov.hk/tc/index/site_pubsvc/page_socsecu/sub_addressesa

[toc] | [prev] | [next] | [standalone]

#2843

Man-wai Chang wrote:

> On 16/08/11 11:02 PM, eBob.com wrote:
>> Is "script" official terminology in PHP? The book I am reading says
>> "Built-in superglobal variables are visible everywhere within a script."
>> but has never explicitly defined "script". (Although there is a hint
>> that maybe everything between tags is a script.)
> 
> In the old days, "Programs" were compiled into binary codes for direct
> execution by the CPU. "Scripts" were not compiled, but interpreted by a
> program called intepreter.

Contrary to popular belief, scripts, i. e. programs written in a scripting 
language, are compiled, too.  They are *JIT-compiled* *at runtime*.

PHP 4+ scripts are compiled by the Zend Engine (a virtual machine, currently 
Zend Engine II), to Zend Opcode, a platform-independent byte code (much like 
with Java).  That byte code is interpreted by that VM.

See also:

- <http://php.net/manual/en/internals2.opcodes.php>
- <http://www.infoworld.com/d/developer-world/zend-hails-php-microsoft-
ibm-733>.


PointedEars
-- 
Danny Goodman's books are out of date and teach practices that are
positively harmful for cross-browser scripting.
 -- Richard Cornford, cljs, <cife6q$253$1$8300dec7@news.demon.co.uk> (2004)

[toc] | [prev] | [next] | [standalone]

#2859

Thomas 'PointedEars' Lahn wrote:
> Man-wai Chang wrote:
> 
>> On 16/08/11 11:02 PM, eBob.com wrote:
>>> Is "script" official terminology in PHP? The book I am reading says
>>> "Built-in superglobal variables are visible everywhere within a script."
>>> but has never explicitly defined "script". (Although there is a hint
>>> that maybe everything between tags is a script.)
>> In the old days, "Programs" were compiled into binary codes for direct
>> execution by the CPU. "Scripts" were not compiled, but interpreted by a
>> program called intepreter.
> 
> Contrary to popular belief, scripts, i. e. programs written in a scripting 
> language, are compiled, too.  They are *JIT-compiled* *at runtime*.
> 

Contrary to popular belief, machine code is interpreted by the CPU's 
microcode, if you REALLY want to be pedantic.

[toc] | [prev] | [next] | [standalone]

#2874

> Contrary to popular belief, machine code is interpreted by the CPU's
> microcode, if you REALLY want to be pedantic.

Could some experts here draw a tree diagram to explain all these? :)

[toc] | [prev] | [next] | [standalone]

#2876

Man-wai Chang wrote:
>> Contrary to popular belief, machine code is interpreted by the CPU's
>> microcode, if you REALLY want to be pedantic.
> 
> Could some experts here draw a tree diagram to explain all these? :)
No need PHP code is 'compiled' into an intermediate language which is 
interpreted by the zend engine which is written in (c? C++?) and so runs 
machine code on the processor, which takes the machine code like  PUSH 
AX interprets it into machine code instructions like 'move this register 
onto the data bus a and put the contents of that other register on the 
address part of the bus, then issue a write memory bit pattern to the 
bus  and increment this register' .

[toc] | [prev] | [next] | [standalone]

#2878

In article <j2jfcg$48l$2@dont-email.me>,
 Man-wai Chang <toylet.toylet@gmail.com> wrote:

> > Contrary to popular belief, machine code is interpreted by the CPU's
> > microcode, if you REALLY want to be pedantic.

That's arguably true *if* the CPU *has* microcode. It may be implemented 
using random logic.

> Could some experts here draw a tree diagram to explain all these? :)

Google.

-- 
Tim

"That excessive bail ought not to be required, nor excessive fines imposed,
nor cruel and unusual punishments inflicted"  --  Bill of Rights 1689

[toc] | [prev] | [next] | [standalone]

#2881

Tim Streater wrote:
> In article <j2jfcg$48l$2@dont-email.me>,
> Man-wai Chang <toylet.toylet@gmail.com> wrote:
> 
>> > Contrary to popular belief, machine code is interpreted by the CPU's
>> > microcode, if you REALLY want to be pedantic.
> 
> That's arguably true *if* the CPU *has* microcode. It may be implemented 
> using random logic.
> 

Most if not all CISC has *some* microcode.

Not sure about ARM chips..

Mostly mnot it seems

[toc] | [prev] | [next] | [standalone]

#2873

>> In the old days, "Programs" were compiled into binary codes for direct
>> execution by the CPU. "Scripts" were not compiled, but interpreted by a
>> program called intepreter.
>
> Contrary to popular belief, scripts, i. e. programs written in a scripting
> language, are compiled, too.  They are *JIT-compiled* *at runtime*.

Is this real compilation? :)

> PHP 4+ scripts are compiled by the Zend Engine (a virtual machine, currently
> Zend Engine II), to Zend Opcode, a platform-independent byte code (much like
> with Java).  That byte code is interpreted by that VM.

So is PHP still a script?

[toc] | [prev] | [next] | [standalone]

#2875

Man-wai Chang wrote:
>>> In the old days, "Programs" were compiled into binary codes for direct
>>> execution by the CPU. "Scripts" were not compiled, but interpreted by a
>>> program called intepreter.
>>
>> Contrary to popular belief, scripts, i. e. programs written in a 
>> scripting
>> language, are compiled, too.  They are *JIT-compiled* *at runtime*.
> 
> Is this real compilation? :)
> 

well its like pascal. Its compiled to an intermediate level interpreterd 
thing.

>> PHP 4+ scripts are compiled by the Zend Engine (a virtual machine, 
>> currently
>> Zend Engine II), to Zend Opcode, a platform-independent byte code 
>> (much like
>> with Java).  That byte code is interpreted by that VM.
> 
> So is PHP still a script?

who gives a damn?

[toc] | [prev] | [next] | [standalone]

#2879

On Fri, 19 Aug 2011 00:40:26 +0800,
Man-wai Chang <toylet.toylet@gmail.com> wrote:

>>> In the old days, "Programs" were compiled into binary codes for direct
>>> execution by the CPU. "Scripts" were not compiled, but interpreted by a
>>> program called intepreter.
>>
>> Contrary to popular belief, scripts, i. e. programs written in a scripting
>> language, are compiled, too.  They are *JIT-compiled* *at runtime*.
>
>Is this real compilation? :)

How do you define "real compilation"?

The principle of compilation, as of assembly, is translate once
(because translation is slow and was costly), and ever after just
run the product of the assembly/compilation process.  

So, given that definition, compiling to p(seudo)-code is just as
much compilation as compiling to machine code.  

Only the execution environment is different:  pcode runs on a
pmachine, a virtual chip implemented in software rather than
hardware and thus potentially able to be run on any hardware to
which that pmachine has been ported.  Machine code runs directly
on the hardware -- but only the specific type of hardware for
which it was written.  Machine-code programs are fast, pcode
programs are slower, source-interpreted programs are slowest.

PHP, like Java, JavaScript, and quite a few other languages,
compiles to pcode, and the programs run on a pmachine.

>
>> PHP 4+ scripts are compiled by the Zend Engine (a virtual machine, currently
>> Zend Engine II), to Zend Opcode, a platform-independent byte code (much like
>> with Java).  That byte code is interpreted by that VM.
>
>So is PHP still a script?

Of course you can call a php program a "script" if you like, but
the traditional name for any coherent, task-oriented set of
computer instructions, regardless of how or whether they are
compiled, is "program". 

I've never seen the point of inventing new names for existing
concepts; all it seems to do is add confusion.  But some people
profit from confusion, so I'm sure that explains at least part of
it.

[toc] | [prev] | [next] | [standalone]

#2915

Man-wai Chang wrote:

>>> In the old days, "Programs" were compiled into binary codes for direct
>>> execution by the CPU. "Scripts" were not compiled, but interpreted by a
>>> program called intepreter.
>>
>> Contrary to popular belief, scripts, i. e. programs written in a
>> scripting language, are compiled, too.  They are *JIT-compiled* *at
>> runtime*.
> 
> Is this real compilation? :)

Yes.

>> PHP 4+ scripts are compiled by the Zend Engine (a virtual machine,
>> currently Zend Engine II), to Zend Opcode, a platform-independent byte
>> code (much like
>> with Java).  That byte code is interpreted by that VM.
> 
> So is PHP still a script?

PHP is a scripting language.  Scripting languages are a subset of 
programming languages.

As a result, a PHP program may be called a PHP script.

This is not an Internet chat, so please leave in the attribution lines.


PointedEars
-- 
Prototype.js was written by people who don't know javascript for people
who don't know javascript. People who don't know javascript are not
the best source of advice on designing systems that use javascript.
  -- Richard Cornford, cljs, <f806at$ail$1$8300dec7@news.demon.co.uk>

[toc] | [prev] | [next] | [standalone]

#2916

On Sat, 20 Aug 2011 19:48:58, Thomas 'PointedEars' Lahn wrote:

> This is not an Internet chat, so please leave in the attribution lines.

He won't, any more than you'll fix your sig.

-- 
Sig Heil!

[toc] | [prev] | [next] | [standalone]

#2919

Samuel Smythe wrote:

> On Sat, 20 Aug 2011 19:48:58, Thomas 'PointedEars' Lahn wrote:
>> This is not an Internet chat, so please leave in the attribution lines.
> 
> He won't, any more than you'll fix your sig.

There is nothing about my sig that needs fixing.  You are confusing a Usenet 
sig with something else.


PointedEars
-- 
Prototype.js was written by people who don't know javascript for people
who don't know javascript. People who don't know javascript are not
the best source of advice on designing systems that use javascript.
  -- Richard Cornford, cljs, <f806at$ail$1$8300dec7@news.demon.co.uk>

[toc] | [prev] | [next] | [standalone]

#2920

On Sat, 20 Aug 2011 23:31:03, Thomas 'PointedEars' Lahn wrote:

> Samuel Smythe wrote:
> 
>> On Sat, 20 Aug 2011 19:48:58, Thomas 'PointedEars' Lahn wrote:
>>> This is not an Internet chat, so please leave in the attribution lines.
>> 
>> He won't, any more than you'll fix your sig.
> 
> There is nothing about my sig that needs fixing.  You are confusing
> a Usenet sig with something else.

See?  I told ya!

> PointedEars   <--- signature

-- 
Sig Heil!

[toc] | [prev] | [next] | [standalone]

#2921

Samuel Smythe wrote:

> On Sat, 20 Aug 2011 23:31:03, Thomas 'PointedEars' Lahn wrote:
>> Samuel Smythe wrote:
>>> On Sat, 20 Aug 2011 19:48:58, Thomas 'PointedEars' Lahn wrote:
>>>> This is not an Internet chat, so please leave in the attribution lines.
>>> He won't, any more than you'll fix your sig.
>> There is nothing about my sig that needs fixing.  You are confusing
>> a Usenet sig with something else.
> 
> See?  I told ya!
> 
>> PointedEars   <--- signature

And the *Usenet* signature is what follows the line with "-- ".  (Told you.)


PointedEars
-- 
Use any version of Microsoft Frontpage to create your site.
(This won't prevent people from viewing your source, but no one
will want to steal it.)
  -- from <http://www.vortex-webdesign.com/help/hidesource.htm> (404-comp.)

[toc] | [prev] | [next] | [standalone]

#2922

On Sun, 21 Aug 2011 00:41:48, Thomas 'PointedEars' Lahn wrote:

> And the *Usenet* signature is what follows the line with "-- ".
> (Told you.)

<sighs>  I didn't say "*Usenet* signature; I said "sig".

-- 
> PointedEars

Sig Heil!

[toc] | [prev] | [next] | [standalone]

Page 1 of 2  [1] 2  Next page →

Back to top | Article view | comp.lang.php

csiph-web