How to set a predefined input

Question

I want a simple pre-defined input in ruby. What I mean is that I want something to be there by default so the user can edit or just simply press Enter to skip. I'm using STDIN.gets.chomp.

not predifiend : "Please enter a title: "
predefined : "Please enter a title: Inception " // "Inception" is pre-defined input]

What have you already tried? What does your code look like? – dpassage Oct 24 '12 at 16:16 — dpassage, Oct 24 '12 at 16:16
print "Title?" title = STDIN.gets.chomp – Kivylius Oct 24 '12 at 16:28 — Kivylius, Oct 24 '12 at 16:28

score 3 · Accepted Answer · answered Oct 24 '12 at 16:17

The following is a sub-optimal solution as the default answer is not cleared instantly as the user begins to type:

prompt = 'Please enter a title: '
default_answer = 'Inception'

# Print the whole line and go back to line start
print "#{prompt}#{default_answer}\r"
# Print only the prompt so that the cursor stands behing the prompt again
print prompt

# Fetch the raw input
input = gets

# If user just hits enter only the linebreak is put in
if input == "\n"
  answer = default_answer
else # Otherwise the typed string including a linebreak is put in
  answer = input.chomp
end

puts answer.inspect

If you want such a thing I guess you have to use more advanced terminal features. I guess ncurses could do the job.

Another option would be to just display the default answer in brackets and simply put the prompt behind that. A lot of simple command line tools do such thing. This could look like this:

 Please enter a title [Inception]:

How to set a predefined input

1 Answers1