NAME
    isfile - whether a value is a file

SYNOPSIS
    isfile(x)

TYPES
    x		any

    return	int

DESCRIPTION
    Determine if x is a file.  This function will return 1 if x is
    a file, 0 otherwise.

EXAMPLE
    > a = files(0)
    > print isfile(a), isfile(files(1)), isfile(1)
    1 1 0

LIMITS
    none

LIBRARY
    none

SEE ALSO
    isassoc, isatty, isblk, isconfig, isdefined, iserror, iseven,
    ishash, isident, isint, islist, ismat, ismult, isnull, isnum, isobj,
    isobjtype, isodd, isprime, isrand, israndom, isreal, isrel,
    issimple, issq, isstr, istype