Re: terminology: "l-value" & "r-value"

2011-01-04 Thread Manfred_Nowak
Steven Schveighoffer wrote:

> please replace

done. :-)

-manfred


Re: terminology: "l-value" & "r-value"

2011-01-04 Thread spir
On Tue, 4 Jan 2011 17:56:53 + (UTC)
"Manfred_Nowak"  wrote:

> > They describe which side of the equation they are on  
> 
> arg, no! please replace "equation" by "assignExpression".

lol, great! this is one of the reasons why in my dream language, assignment 
would be denoted by any other sign *but* "=".

Denis
-- -- -- -- -- -- --
vit esse estrany ☣

spir.wikidot.com



Re: terminology: "l-value" & "r-value"

2011-01-04 Thread Steven Schveighoffer
On Tue, 04 Jan 2011 12:56:53 -0500, Manfred_Nowak   
wrote:



Steven Schveighoffer wrote:


They describe which side of the equation they are on


arg, no! please replace "equation" by "assignExpression".


please replace arg with argh!

;)

But whatever floats your boat.

-Steve


Re: terminology: "l-value" & "r-value"

2011-01-04 Thread Manfred_Nowak
Steven Schveighoffer wrote:

> They describe which side of the equation they are on

arg, no! please replace "equation" by "assignExpression".

-manfred


Re: terminology: "l-value" & "r-value"

2011-01-04 Thread Steven Schveighoffer

On Tue, 04 Jan 2011 08:55:07 -0500, spir  wrote:


Hello,

I'm bluffed by the 2 terms "l-value" & "r-value" used in C-line language  
common terminologies. I think I guess what they mean, but I don't  
understand the need for such absconse idioms. Why not:

l-value <-> variable
r-value <-> value (or expression)
?

I guess (*p) is considered an l-value. Indeed, it's a special way of  
denoting a variable, matching the special case of a pointer. If correct,  
this requires slightly extending the notion of variable (and/or of  
identifier).
On the r-value side, I cannot find anything that makes it a distinct  
concept from the one of value, or of expression.


Explanations welcome, thank you,
Denis


lvalue stands for left value, rvalue stands for right value.  They  
describe which side of the equation they are on:


lvalue = rvalue;

Why these terms instead of something more natural?  Well, I have no idea  
:)  If I were to guess, it would be that no natural term could exactly  
describe the meaning, and also that using natural terms are subjective.   
There's no mistaking what lvalue and rvalue mean becausey they are defined  
by the language itself.


I'm sure Walter probably knows the origin, l and r values are really  
compiler terms, and he's been writing compilers for a long time.


-Steve


Re: terminology: "l-value" & "r-value"

2011-01-04 Thread Pelle

On 01/04/2011 02:55 PM, spir wrote:

Hello,

I'm bluffed by the 2 terms "l-value"&  "r-value" used in C-line language common 
terminologies. I think I guess what they mean, but I don't understand the need for such absconse 
idioms. Why not:
l-value<->  variable
r-value<->  value (or expression)
?

I guess (*p) is considered an l-value. Indeed, it's a special way of denoting a 
variable, matching the special case of a pointer. If correct, this requires 
slightly extending the notion of variable (and/or of identifier).
On the r-value side, I cannot find anything that makes it a distinct concept 
from the one of value, or of expression.

Explanations welcome, thank you,
Denis
-- -- -- -- -- -- --
vit esse estrany ☣

spir.wikidot.com



rvalue is easier than value-not-bound-to-a-memory-address.

lvalue is easier than value-with-memory-address.

Both lvalues and rvalues are values, both can be expressions, and 
lvalues doesn't have to be variables.


Perhaps a better terminology could have been chosen, but changing them 
doesn't provide real benefits, as far as I can tell.


terminology: "l-value" & "r-value"

2011-01-04 Thread spir
Hello,

I'm bluffed by the 2 terms "l-value" & "r-value" used in C-line language common 
terminologies. I think I guess what they mean, but I don't understand the need 
for such absconse idioms. Why not:
l-value <-> variable
r-value <-> value (or expression)
?

I guess (*p) is considered an l-value. Indeed, it's a special way of denoting a 
variable, matching the special case of a pointer. If correct, this requires 
slightly extending the notion of variable (and/or of identifier).
On the r-value side, I cannot find anything that makes it a distinct concept 
from the one of value, or of expression.

Explanations welcome, thank you,
Denis
-- -- -- -- -- -- --
vit esse estrany ☣

spir.wikidot.com