matrix coercion, logical -> character

Anyone know whether this is intentional, and by which rationale?
(R-devel on RedHat, but hardly new)

It is documented:

     'as.matrix' is a generic function. The method for data frames will
     convert any non-numeric column into a character vector using
     'format' and so return a character matrix.

Remember than not some long ago you could not have logical columns in data 
frames: they were coerced to factors.

It would be easy to change to allow numeric, logical or character 
matrices.

l <- data.frame(a=rpois(10,1)>0,b=rpois(10,1)>0)
apply(l,1,which)

Error in FUN(newX[, i], ...) : argument to "which" is not logical

lapply(l,mode)

$a
[1] "logical"

$b
[1] "logical"

mode(as.matrix(l))

[1] "character"

Brian D. Ripley,                  ripley@stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595