Isaiah Gilliland wrote:
I've been trying to figure out how to create a cli app. My first issue is to
create a prompt for the user to enter text so I can use what they enter.
I've somewhat found out how to make outside commands to other programs, but
I've ben scouring the documentation for some time and I can't find what I'm
looking for. Is there anyone out there with an example I can use or the
right documentation I've missed. Loving Racket alot, take care.
The Racket Guide has a section on "Input and Output". It doesn't have
the example you're looking for, but it has useful background info.
http://docs.racket-lang.org/guide/i_o.html
When you run a command-line Racket program, (current-input-port) gets
input from the terminal. You can use display or printf to emit a prompt,
then use read-line to get the user input. Here's a little example. Save
it in a file and then run "racket <filename>" in the shell.
#lang racket
(define (loop counter)
(printf "~a# " counter)
(let ([command (read-line (current-input-port) 'any)])
(cond [(or (eof-object? command) (equal? command "quit"))
(printf "Good-bye!\n")]
[(string? command)
(printf "You said, ~s\n" command)
(printf "Say quit to end.\n")
(loop (add1 counter))])))
(loop 1)
To parse the commands, you can use regular expressions (eg regexp-match)
or an LALR(1) grammar (search for "parser tools").
Ryan
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