[R] How to Describe R to Finance People
tplate at blackmesacapital.com
Tue Jun 8 18:49:09 CEST 2004
At Monday 07:58 PM 6/7/2004, Richard A. O'Keefe wrote:
>There are three perspectives on programming languages like the S/R family:
>(1) The programming language perspective.
> I am sorry to tell you that the only excuse for R is S.
> R is *weird*. It combines error-prone C-like syntax with data structures
> that are APL-like but not sufficiently* APL-like to have behaviour that
> is easy to reason about. The scope rules (certainly the scope rules for
> S) were obviously designed by someone who had a fanatical hatred of
> compilers and wanted to ensure that the language could never be usefully
What in particular about the scope rules for S makes it tough for
compilers? The scope for ordinary variables seems pretty straightforward
-- either local or in one of several global locations. (Or are you
referring to the feature of the get() function that it can access variables
in any frame?)
> Thanks to 'with' the R scope rules are little better. The
> fact that (object)$name returns NULL instead of reporting an error when
> the object doesn't _have_ a $name property means that errors can be
> delayed to the point where debugging is harder than it needs to be.
Yup, that's why I proposed (and provided an implementation) of an
alternative "$$" operator that did report an error when object$$name didn't
have a "name" component (and also didn't allow abbreviation), but there was
no interest shown in incorporating this into R.
-- Tony Plate
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