R/INTERNAL-scalaInvoke.R

In rscala: Bridge Between 'R' and 'Scala' with Callbacks

scalaInvoke <- function(details, snippet, args, envir, withNames=FALSE, withReference=FALSE, transcompileInfo=NULL) {
  if ( ( ! is.vector(snippet) ) || ( length(snippet) != 1 ) ) stop("'snippet' should be a character vector of length one.")
  if ( details[["disconnected"]] ) scalaConnect(details)
  scalaLastEngine(details)
  if ( details[["interrupted"]] ) return(invisible())
  socketOut <- details[["socketOut"]]
  if ( length(details[["garbage"]]) > 0 ) {
    # Careful!  R's garbage collector can mutate 'details[["garbage"]]'.
    wb(socketOut,PCODE_GARBAGE_COLLECT)
    what <- details[["garbage"]]
    wb(socketOut,c(length(what),what))
    details[["garbage"]] <- setdiff(details[["garbage"]],what)
  }
  args <- rev(args)
  names <- names(args)
  for ( i in seq_along(args) ) {
    result <- push(args[[i]], names[i], socketOut) 
    if ( ! identical(result,TRUE) ) {
      if ( i > 1 ) {
        wb(socketOut,PCODE_CLEAR)
        wb(socketOut,as.integer(i-1L))
      }
      stop(attr(result,"msg"))
    }
  }
  if ( withReference ) {
    wb(socketOut,PCODE_INVOKE_WITH_REFERENCE)
  } else {
    if ( withNames ) wb(socketOut,PCODE_INVOKE_FREEFORM)
    else wb(socketOut,PCODE_INVOKE)
  }
  len <- if ( is.null(args) ) -1L else length(args)
  wb(socketOut,len)
  wc(socketOut,snippet)
  pop(details, transcompileInfo, envir)
}