Re: user-defined function & string file name

[Juergen W. <wie...@fr...>]

Ethan Merritt wrote:
> I will consolidate the (isstring() || isstringvar()) test into a single
> call isstringvalue().  This simplifies the code, which is good.
> If/when Juergen comes up with a fully working isstringfunc(), that can be
> added at a single point in isstringvalue().

This is tricky.  The functions isstring() and isstringvar() only
check the next token if it is/contains a string.  The current syntax
implies that the whole expression has to be a string then.  A call
to isstring() and isstringvar() is thus safe.

A function isstringfunc() will have to evaluate the whole
expression.  This should only be tried if we know that the syntax
requires an expression.  Such a function must not be called if the
next token can be a key word.  An invalid expression would lead to
an int_error().

Theoretically, this could be implemented.  But it means that all
command line parsing would have to check for key words *before* the
call to isstringfunc() [or an extended isstring()].  All call sites
in the sources would have to be checked and quite few would have to
be rewritten if they were to use isstringfunc().

BTW: I wouldn't like to evaluate an expression and to throw away
everything but the type of the result.  The function
try_to_get_string() seems more appropriate in the cases where
isstringfunc() can be used.

> By my current count there are 14 of these consolidated tests,
> as compareded to  ~60 remaining instances of the original isstring().
>
> So I agree with you in principle, but let's get the simplified code
> checked out first before considering a grand re-naming.


Juergen