Re: Top 10 most common hard skills listed on resumes...

Bart <bc@freeuk.com> writes:

On 28/08/2024 00:49, Ben Bacarisse wrote:

Indeed, and BLISS is not like that.  I had hoped to shed some light on
why there is some logic to BLISS's rather idiosyncratic design.
 

Given a declaration like 'int A' then:
>
                            BLISS   C
>
Read or write A's value   .A       A

I don't think that's right.  To change the value at address A (what I
think you mean by "write A's value") you write
   A = 42;
in BLISS.  And to add one to the value at address A you write
   A = .A + 1;

>
OK. That's just makes it more bizarre than I'd thought.

Curious.  It's what makes it consistent, though it is definitely an
uncommon approach.

The example I saw
included these lines:
>
    GETNUM(X);            ! returns a value via X
    Y = STEP(.X);
    PUTNUM(.Y)
>
So in an rvalue context:  X reads its address; while .X reads its
value.

The whole point is to remove the two contexts.  A variable name is
/always/ an lvalue (which is why it can be assigned).  C has an implicit
lvalue to rvalue conversion in the contexts you have come to expect it.
BLISS does not.  You always need a dot to convert to an rvalue.

But in an lvalue one:     Y writes its value; .Y may not be defined
>
It looks asymmetric. C like most languages is symmetric, you write 'A = A'
with the same syntax on both sides.

Since assignment is inherently asymmetric (you can't write 3 = A but you
can write A = 3) C's syntactic symmetry hides a semantic difference.
What is needed on the two sides is not the same.

I assume that in BLISS, A = A is legal, but does something odd like copy
A's address into itself.

What's odd about that?  And why call is a copy operation?  Do you think
of A = 42 as a copy operation?  BLISS is a low-level system language.

--
Ben.