R/value.R

In mslegrand/pegr: PEG PARSER

#' Returns the value of a parsing  result
#' 
#' @return A list containing the values computed
#' @examples
#' # Select the matching pair of from the alternatives
#' peg<-new.parser()
#' peg<-add_rule(peg, "R<-('a'/'c') ('b' / 'd')")
#' apply_rule(peg, "R", 'ad')->res
#' value(res)
#' 
#' # double all occurances of all vowels
#' peg<-new.parser()
#' peg<-add_rule(peg, "V<-'a' / 'e' / 'i' / 'o' / 'u' ")
#' peg<-add_rule(peg, "C<-(!V .)")
#' peg<-add_rule(peg, "A<- (V / C)+" )
#' peg<-set_action(peg, "V", "c(v[1],v[1])" )
#' peg<-set_action(peg, "A", "list(paste0(v,collapse=''))" )
#' apply_rule(peg, "A", "the big bad wolf", exe=TRUE)->res
#' value(res)[1]
#' @export
value<-function(res){
  if(!("PEGResult" %in% class(res))){ stop("Argument not a peg parsing result", call. = FALSE)} 
  return(res$val) 
}