[R] stringification magic in subset?

[ivo welch]

dear R wizards:

I am trying to replace subset() with my own version that first checks
that each name in the select statement has a corresponding name in the
data set.  preferably, it would have the same syntax and semantics as
subset() otherwise.

alas, subset works in interesting ways:

subset(d, select=col1)

works just like

subset(d, select="col1")

somehow, subset manages to "stringify" its argument in such cases.  Is
it possible to duplicate the subset method one-for-one?

a minor question---where do I find the source definition such as that
of subset(), which is defined in

> subset
function (x, ...)
UseMethod("subset")
<environment: namespace:base>
>

any help, as usual, appreciated.

regards,

/ivo