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Keith Thompson <Keith.S.Thompson+u@gmail.com> writes:Ben Bacarisse <ben@bsb.me.uk> writes:>Bart <bc@freeuk.com> writes:>BLISS is a rather strange language. For something supposedly low level than>
C, it doesn't have 'goto'.
>
It is also typeless.
>
There is also a key feature that sets it apart from most HLLs: usually if
you declare a variable A, then you can access A's value just by writing A;
its address is automatically dereferenced.
Not always. This is where left- and right-evaluation came in. On the
left of an assignment A denotes a "place" to receive a value. On the
right, it denotes a value obtained from a place. CPL used the terms and
C got them via BCPL's documentation. Viewed like this, BLISS just makes
"evaluation" a universal concept.
As I recall, the terms "lvalue" and "rvalue" originated with CPL. The
'l' and 'r' suggest the left and right sides of an assignment.
>
Disclaimer: I have a couple of CPL documents, and I don't see the terms
"lvalue" and "rvalue" in a quick look. The PDFs are not searchable. If
someone has better information, please post it. Wikipedia does say that
the notion of "l-values" and "r-values" was introduced by CPL.
I presume, since I mentioned the concepts coming from CPL, you are
referring to specifically the short-form terms l- and r-values?
>
I can't help with those specific terms as the document I have uses a
mixture of terms like "the LH value of...", "left-hand expressions" and
"evaluated in LH mode".
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