Times that don't turn into a pumpkin at midnight

bentime.R

"+.bentime"<-function(e1,e2){
	   e<-list(hour=e1$hour+e2$hour,min=e1$min+e2$min,sec=e1$sec+e2$sec)
	   sec_overflow<-e$sec>60L
	   e$sec<-e$sec %% 60L
	   e$min<-e$min+sec_overflow
	   min_overflow<-e$min>60L
	   e$hour<-e$hour+min_overflow
	   e$min<-e$min %% 60L
	   class(e)<-"bentime"
	   e
	}

"-.bentime"<-function(e1,e2){
	   e<-list(hour=e1$hour-e2$hour,min=e1$min-e2$min,sec=e1$sec-e2$sec)
	   sec_overflow<-e$sec<0L
	   e$sec<-e$sec %% 60L
	   e$min<-as.integer(e$min-sec_overflow)
	   min_overflow<-e$min< 0L
	   e$hour<-as.integer(e$hour-min_overflow)
	   e$min<-e$min %% 60L
	   class(e)<-"bentime"
	   e
	}


bentime<-function(hour,min,sec){
	rval<-list(hour,min,sec)
	class(rval)<-"bentime"
	}
	
print.bentime<-function(x,...) cat(paste(x$hour, formatC(x$min,width=2,digits=0,flag=0), formatC(x$sec,width=2,digits=0,flag=0),sep=":"))

as.bentime <-function(x,...) UseMethod("as.bentime")

as.bentime.POSIXlt<-function(x,...){
	rval<-unclass(x)[c("hour","min","sec")]
    class(rval)<-"bentime"
    rval
    }

as.bentime.character<-function(x,...){
	y<-as.POSIXlt(x,format="%H:%M:%S")
	as.bentime(y)
	}    

example.R

a<-as.bentime("16:45:00")
b<-as.bentime("9:20:00")
a
b
a+b
a-b
(a+b)-b