ask: Obtain Input from User With Error Handling
In runjags: Interface Utilities, Model Templates, Parallel Computing Methods and Additional Distributions for MCMC Models in JAGS

ask	R Documentation

Obtain Input from User With Error Handling

A simple function to detect input from the user, and keep prompting until a response matching the class of input required is given.

ask(prompt = "?", type = "logical", bounds = c(-Inf, Inf), na.allow = FALSE)

`prompt`	what text string should be used to prompt the user? (character string)
`type`	the class of object expected to be returned - "logical", "numeric", "integer", "character". If the user input does not match this return, the prompt is repeated
`bounds`	the lower and upper bounds of number to be returned. Ignored if type is "logical" or "character".
`na.allow`	if TRUE, allows the user to input "NA" for any type, which is returned as NA