Re: What is the meaning of an expression?

Roger L Costello <costello@mitre.org> schrieb:


> In some book I read this statement:
>
> The meaning of an expression is
> the value of the expression.


Jumping in late...


Computer science teminology can unfortunately be imprecise, and
different people and different documents use different words for
meaing the same thing, and vice versa.


If you want to know what expression means in a particular language,
look at its standards documents. For example, Fortran states
(F2018, 10.1.1)


# An expression represents either a data object reference
# or a computation, and its value is either a scalar or an
# array. Evaluation of an expression produces a value, which has a
# type, type parameters (if appropriate), and a shape (10.1.9).


whereas C states (n2596)


# An expression is a sequence of operators and operands that
# specifies computation of a value,92) or that designates an object
# or a function, or that generates side effects, or that performs
# a combination thereof.


so the two languages obviously have different meanings for the
term, and applying one definition to the other language is likely
to lead to confusion (such as about side effects in Fortran
expressions).


I find no definiton of "meaining" in either standard, so although
your question contains the word "meaning", I do not think it
is meaningful. Know what I mean?

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