On Mon, Mar 4, 2024 at 8:45 AM luke-tierney--- via R-devel
wrote:
>
> Comparison operators == and != can be used on language objects
> (i.e. call objects and symbols). The == operator in particular often
> seems to be used as a shorthand for calling identical(). The current
> implementation involv
That's a good suggestion, but if the function accepts strings, the
problem is fairly easy using the parser. E.g. compare
> getParseData( parse(text="x1 + x2 -> a3") )
line1 col1 line2 col2 id parenttoken terminal text
11 11 1 13 11 0 exprFALSE
7 1
Maybe someone has already suggested this, but if your functions accepted
strings you could use sub or gsub to replace the -> with a symbol that
parsed at the same precedence as <-,
say <<-. Then parse it and deal with it. When it is time to display the
parsed and perhaps manipulated formulae to t
Comparison operators == and != can be used on language objects
(i.e. call objects and symbols). The == operator in particular often
seems to be used as a shorthand for calling identical(). The current
implementation involves comparing deparsed calls as strings. This has
a number of drawbacks and w
Dear Barry,
In general, I believe users are already accustomed with the classical
arrows "->" and "<-" which are used as such in quoted expressions.
But I agree that "-.>" is a very neat trick, thanks a lot. A small dot,
what a difference.
All the best,
Dmitri
On Mon, Mar 4, 2024 at 11:40 AM Bar
It seems like you want to use -> and <- as arrows with different meanings
to "A gets the value of B" in your package, as a means of writing
expressions in your package language.
Another possibility would be to use different symbols instead of the
problematic -> and <-, for example you could use <.
