Compare two tables with the same structure by merging them

compare.tables <- function(d1, d2, by.idx = 1)
{ 
    ## Purpose: Compare two tables with the same structure by merging them. 
    ## Arguments:
    ##    d1: table A
    ##    d2: table B
    ##    by.idx: an index vector to common variables.
    ## Return: a full joined table for comparision

    b <- names(d1)[by.idx]
    d <- full_join(d1, d2, by = b)
    tex.print(d, type = "HTML")
    invisible(d)
}
if (F) {                                # Unit Test
    d1 <- rc()
    d2 <- rc()
    by.idx <- 1:4
    compare.tables(d1, d2, by.idx)
}