[Lazarus] Passing properties as var paramatars

[Mehmet Erol Sanliturk]

Marco van de Voort wrote:
> On Sun, Nov 08, 2009 at 12:17:35AM +0000, Howard Page-Clark wrote:
>>>> On Sat, 7 Nov 2009, Marco van de Voort wrote:
>>>>> This is not orthogonal. VAR parameters are generally updated
>>>>> instantaniously. By delaying the update over a temp variable you break
>>>>> another aspect of the VAR parameter.
>> I don't understand 'not orthogonal' in this sentence. What meaning does
>> orthogonal have apart from 'being at right angles to' ?
> 
> I'm not entirely sure where the phrase comes from (see also Mehmet), but I
> guess it has something to do with the axises in a Carthesian coordinate
> system, and from there dimensions (point,length,area,volume etc). 
> A translation along one axis doesn't change the other in classic geometry.
> 
> Assume it came to indicate absence of side-effects from there.
> 
> 
> --
> 


If you search

orthogonality in programming language design

in www.yahoo.com , you may find many references , such as



http://en.wikipedia.org/wiki/Programming_language_design
http://en.wikipedia.org/wiki/Orthogonality_(programming)

Design Criteria for a Language :
http://www.ist.rit.edu/~jdb/plc/wk1.pdf

Orthogonality in Language Design - Why and how to fake it :
http://prog.vub.ac.be/~wdmeuter/PostJava/Herrmann.pdf

Compactness and Orthogonality :
http://catb.org/esr/writings/taoup/html/ch04s02.html

On orthogonality in programming languages :
http://portal.acm.org/citation.cfm?id=954246&dl=ACM&coll=portal&CFID=934114&CFTOKEN=43879943


The Art of Unix Programming :
( To design for compactness and orthogonality ... )
http://www.linuxtopia.org/online_books/programming_books/art_of_unix_programming/ch04s02_4.html



among many others .


Abundance of references show that orthogonality is a widely considered 
concept in programming language design .

As an example , the following statements are not orthogonal to each other :

( 1 ) if - go to
( 2 ) for
( 3 ) repeat
( 4 ) while
( 5 ) case

because any one of them may be expressed by the others , but

( 1 ) go to
( 2 ) := ( assignment )

are orthogonal because it is not possible to express any one of them by 
the other .


Thank you very much .

Mehmet Erol Sanliturk