Re: Why is the continuation character (the HYPHEN)needed in some situations *at all* ??

[billfen]

I certainly agree - don't mess with the continuation convention.
Consider the following two lines under Thomas' suggestion:

a = b -
c

Is that the equivalent of "a = b - c;" or is it "a = b || ' ' || c;" ?


Original Message:
-----------------
From: Chip Davis [hidden email]
Date: Tue, 31 Jan 2012 18:37:29 +0000
To: [hidden email]
Subject: Re: [Ibm-netrexx] Why is the continuation character (the
HYPHEN)needed in some situations *at all* ??


I don't know, Tom.  I can think of only a half-dozen reasons off the
top of my head why this should be added to your (rather lengthy) list
of bad ideas:

  1. A single rule is easier to learn than one with lots of exceptions
('i' before 'e', except after 'c', unless you have a weird foreign
scientist for a neighbor who studies ancient species at their height...).

  2. A consistently applied rule is easier to remember than one with
lots of idiosyncratic shortcuts.  If my students learn that they don't
_really_ have to enclose multiple statements following an 'Otherwise"
in a 'Do-End' block, it's not my fault.  More often than not, a
student will learn that there is a shortcut, and proceed to mis-apply it.

  3. Error detection and reporting is easier and more accurate when
there is a consistent rule.

  4. Source code processors (pretty-printers, code analyzers, etc.)
would have a much more difficult syntax to parse.

  5. It's not backwards-compatible.  New code would not compile
correctly with older NetRexx processors, even if it uses no new
capabilities.

  6. The advantage (omitting one character) does not offset the
increased complexity and the problems caused.

Thomas, when precision is important (legal contracts, driving
directions, nuclear power plant operations manuals) you don't find the
use of Twitter spelling or syntax. (OMG! X #3 pmp & drp B4C rods b4 it
bloz!)

Can you offer a single, cogent reason why such a change would be
advantageous?  Or are you just pissing in the punchbowl again?

-Chip-

On 1/31/12 13:45 Thomas Schneider said:

> Why do we need (in NetRexx) the HYPHEN as the continuation character in
> the foillowing situations:
>
> a) a line of code is finished by an ordinary OPERATOR (as +, -, *,/,**,
> etc)
>     ... except the BLANK Operator (of course <grin>)
> b) the next line is INITIATED by an ATTRIBUTE (as I call those
> keywords), as
>
> class abc(myparm1=Rexx, myparm2=int 0)
>    uses RexxMsg, RexxFunc
>
> my proposal would be to (quietly) ALLOW those notations (i.e. the
> missing HYPHEN) when we
> all do agree that this would be a step forward into the right direction,
> of course :-)
>
> What do you think?

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[billfen]

>From a scanner/parser point of view, I would have preferred that the
continuation character take precedence over comments, so that

a = b /* this is a valid continuation */ -  
a = b - /* not a valid continuation */

I think that is more confusing than freeing, but it is easy to understand
why it was implemented that way.  More troubling is the fact that Rexx and
NetRexx use different continuation characters, but again, understandable.

Other languages, like the C preprocessor, require that there be no
whitespace after the continuation character, and I think that is too
limiting.  Another version of the language might adopt the convention that
for continued lines, the last non-whitespace character is the continuation
character.  But I suspect that Mike might disagree.  


Original Message:
-----------------
From: Rick McGuire [hidden email]
Date: Tue, 31 Jan 2012 14:00:54 -0500
To: [hidden email]
Subject: Re: [Ibm-netrexx] Why is the continuation character (the
HYPHEN)needed in some situations *at all* ??


Add that this will also break future upward compatibility, since
adding a subkeyword to an instruction might cause two clauses that
were not originally continued to suddenly be considered a single
clause.  Certain runs counter to all of the care Mike put into ensure
future language changes don't break things.

Rick

On Tue, Jan 31, 2012 at 1:37 PM, Chip Davis <[hidden email]> wrote:
> I don't know, Tom.  I can think of only a half-dozen reasons off the top
of
> my head why this should be added to your (rather lengthy) list of bad
ideas:
>
>  1. A single rule is easier to learn than one with lots of exceptions ('i'
> before 'e', except after 'c', unless you have a weird foreign scientist
for
> a neighbor who studies ancient species at their height...).
>
>  2. A consistently applied rule is easier to remember than one with lots
of
> idiosyncratic shortcuts.  If my students learn that they don't _really_
have
> to enclose multiple statements following an 'Otherwise" in a 'Do-End'
block,
> it's not my fault.  More often than not, a student will learn that there
is
> a shortcut, and proceed to mis-apply it.
>
>  3. Error detection and reporting is easier and more accurate when there
is

> a consistent rule.
>
>  4. Source code processors (pretty-printers, code analyzers, etc.) would
> have a much more difficult syntax to parse.
>
>  5. It's not backwards-compatible.  New code would not compile correctly
> with older NetRexx processors, even if it uses no new capabilities.
>
>  6. The advantage (omitting one character) does not offset the increased
> complexity and the problems caused.
>
> Thomas, when precision is important (legal contracts, driving directions,
> nuclear power plant operations manuals) you don't find the use of Twitter
> spelling or syntax. (OMG! X #3 pmp & drp B4C rods b4 it bloz!)
>
> Can you offer a single, cogent reason why such a change would be
> advantageous?  Or are you just pissing in the punchbowl again?
>
> -Chip-
>
>
> On 1/31/12 13:45 Thomas Schneider said:
>>
>> Why do we need (in NetRexx) the HYPHEN as the continuation character in
>> the foillowing situations:
>>
>> a) a line of code is finished by an ordinary OPERATOR (as +, -, *,/,**,
>> etc)
>>    ... except the BLANK Operator (of course <grin>)
>> b) the next line is INITIATED by an ATTRIBUTE (as I call those keywords),
>> as
>>
>> class abc(myparm1=Rexx, myparm2=int 0)
>>   uses RexxMsg, RexxFunc
>>
>> my proposal would be to (quietly) ALLOW those notations (i.e. the missing
>> HYPHEN) when we
>> all do agree that this would be a step forward into the right direction,
>> of course :-)
>>
>> What do you think?
>
>
> _______________________________________________
> Ibm-netrexx mailing list
> [hidden email]
> Online Archive : http://ibm-netrexx.215625.n3.nabble.com/
>

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[Mike Cowlishaw]

> >From a scanner/parser point of view, I would have preferred that the
> continuation character take precedence over comments, so that
>
> a = b /* this is a valid continuation */ - a = b - /* not a
> valid continuation */
>
> I think that is more confusing than freeing, but it is easy
> to understand why it was implemented that way.

Comments nest and override all other syntax so it is easy to 'comment out' a
section of code without needing a new syntax.

> More
> troubling is the fact that Rexx and NetRexx use different
> continuation characters, but again, understandable.

20/20 hindsight ...

> Other languages, like the C preprocessor, require that there
> be no whitespace after the continuation character, and I
> think that is too limiting.  Another version of the language
> might adopt the convention that for continued lines, the last
> non-whitespace character is the continuation
> character.  But I suspect that Mike might disagree.  

Whitespace is not visible, so requiring it does not 'work'.  Last non-whitespace
character?  Alphabetics, too?

Mike

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[ThSITC]

As I did say: EXCEPT for the ABUT and BLANK operation.

I only wanted to raise a discussion, again, but am NOT intending to change
ANYTHING in the NetRexx Language without the approval of the respective
board.

But I do also (quietly) already allow:

call abc(p1,p2,p3)

in Classic Rexx (with a warning) in Rexx2Nrx since years ... ;-)

Leave this totally up to the more knowledgable persons.

But as I'm so heavily switching compuer languages (PL/I, COBOL, Rexx,
NetRexx)
I'm simply forgetting (myself) the rules of each of them.

Maybe the time to invent my own language (Rey: Rexx for Java ??) ;-)

Thomas.
===================================================================.

Am 31.01.2012 19:57, schrieb [hidden email]:

> I certainly agree - don't mess with the continuation convention.
> Consider the following two lines under Thomas' suggestion:
>
> a = b -
> c
>
> Is that the equivalent of "a = b - c;" or is it "a = b || ' ' || c;" ?
>
>
> Original Message:
> -----------------
> From: Chip Davis [hidden email]
> Date: Tue, 31 Jan 2012 18:37:29 +0000
> To: [hidden email]
> Subject: Re: [Ibm-netrexx] Why is the continuation character (the
> HYPHEN)needed in some situations *at all* ??
>
>
> I don't know, Tom.  I can think of only a half-dozen reasons off the
> top of my head why this should be added to your (rather lengthy) list
> of bad ideas:
>
>    1. A single rule is easier to learn than one with lots of exceptions
> ('i' before 'e', except after 'c', unless you have a weird foreign
> scientist for a neighbor who studies ancient species at their height...).
>
>    2. A consistently applied rule is easier to remember than one with
> lots of idiosyncratic shortcuts.  If my students learn that they don't
> _really_ have to enclose multiple statements following an 'Otherwise"
> in a 'Do-End' block, it's not my fault.  More often than not, a
> student will learn that there is a shortcut, and proceed to mis-apply it.
>
>    3. Error detection and reporting is easier and more accurate when
> there is a consistent rule.
>
>    4. Source code processors (pretty-printers, code analyzers, etc.)
> would have a much more difficult syntax to parse.
>
>    5. It's not backwards-compatible.  New code would not compile
> correctly with older NetRexx processors, even if it uses no new
> capabilities.
>
>    6. The advantage (omitting one character) does not offset the
> increased complexity and the problems caused.
>
> Thomas, when precision is important (legal contracts, driving
> directions, nuclear power plant operations manuals) you don't find the
> use of Twitter spelling or syntax. (OMG! X #3 pmp&  drp B4C rods b4 it
> bloz!)
>
> Can you offer a single, cogent reason why such a change would be
> advantageous?  Or are you just pissing in the punchbowl again?
>
> -Chip-
>
> On 1/31/12 13:45 Thomas Schneider said:
>> Why do we need (in NetRexx) the HYPHEN as the continuation character in
>> the foillowing situations:
>>
>> a) a line of code is finished by an ordinary OPERATOR (as +, -, *,/,**,
>> etc)
>>      ... except the BLANK Operator (of course<grin>)
>> b) the next line is INITIATED by an ATTRIBUTE (as I call those
>> keywords), as
>>
>> class abc(myparm1=Rexx, myparm2=int 0)
>>     uses RexxMsg, RexxFunc
>>
>> my proposal would be to (quietly) ALLOW those notations (i.e. the
>> missing HYPHEN) when we
>> all do agree that this would be a step forward into the right direction,
>> of course :-)
>>
>> What do you think?
> _______________________________________________
> Ibm-netrexx mailing list
> [hidden email]
> Online Archive : http://ibm-netrexx.215625.n3.nabble.com/
>
>
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>
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>

--
Thomas Schneider (Founder of www.thsitc.com) Member of the Rexx Languge
Asscociation (www.rexxla.org) Member of the NetRexx Developer's Team
(www.netrexx.org)

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