R/td.expression.R

In nonsleepr/teradataR: Teradata R Package

Ops.td.expression <- function(e1, e2) {
    aparen <- bparen <- FALSE
    if (!missing(e1)) {
        da <- deparse(substitute(e1))
        if (substr(da, 1, 1) == "(" && substr(da, nchar(da), nchar(da)) == ")") 
            aparen <- TRUE
    }
    if (!missing(e2)) {
        db <- deparse(substitute(e2))
        if (substr(db, 1, 1) == "(" && substr(db, nchar(db), nchar(db)) == ")") 
            bparen <- TRUE
    }
    op = .Generic
    if (op == "%%") 
        op = "mod"
    if (is.td.data.frame(e1)) 
        aval <- paste("\"", names(e1), "\"", sep = "")
    if (is.numeric(e1) || is.character(e1) || is.td.expression(e1)) 
        aval <- e1
    if (missing(e2)) {
        if (aparen) 
            aval <- paste("(", aval, ")", sep = "")
        val <- paste(aval, op)
        class(val) <- "td.expression"
        return(val)
    }
    if (is.td.data.frame(e2)) 
        bval <- paste("\"", names(e2), "\"", sep = "")
    if (is.numeric(e2) || is.character(e2) || is.td.expression(e2)) 
        bval <- e2
    
    if (aparen) 
        aval <- paste("(", aval, ")", sep = "")
    if (bparen) 
        bval <- paste("(", bval, ")", sep = "")
    
    val <- paste(aval, op, bval)
    class(val) <- "td.expression"
    return(val)
}

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