Exit Statuses TryCatch in R

trycatch.R

#' Trycatch in R is setup in a really weird way. Usually you enter 3+ conditions as parameters (message, warning, error) and the function you would like run to handle the exception. 
#" As such, you want to make use of the return command to return an exit status 

#' The big caveat is that you want to use return to give exit statuses, but for the expression to be 'tried' itself, you can't use return (unless youwant to wrap the expression in a function, which is a pain.
#' To get an exit status, then you want to code the last part of the expression to return your exit status in the expression and the alternative exit statuses as return statements in the other parameters to trycatch


#' example:
exit_status<-tryCatch({
x<-1
y<-2
m<-1
0
},
warning=function(warn){print(warn)
return(1)})

# returns an 'exit_staus' of 0, and defines x,y,m in the global environment

exit_status<-tryCatch({
x<-1
y<-2
m<-1
0
},
warning=function(warn){warning(warn)
return(1)})

# defines x an y, gives error for m and yeilds exit status of 1
exit_status<-tryCatch({
x<-1
y<-2
m<-warning("oh noes")
0
},
warning=function(warn){warning(warn)
return(1)})