I thought I had understood mostly everything I learned in Beautiful
Racket. But I must be very confused as a whole. I gave myself the task of
translating something like this
#lang tcp
connect www.google.com 80
text GET / HTTP/1.1
text Host: www.google.com
text
read-until-eof
exit
into something like this
#lang racket/base
(require racket/tcp)
(require racket/port)
(define host "www.google.com")
(define port 80)
(define-values (input-port output-port)
(tcp-connect host port))
(define (sendline ln)
(display ln (current-output-port))
(display ln output-port)
(flush-output output-port))
(displayln (format "Connected @ ~a on port ~a." host port))
(sendline "GET / HTTP/1.1\r\n")
(sendline (format "Host: ~a\r\n\r\n" host))
(write (port->lines input-port))
(exit)
I've achived a bit. I translated that dsl-source into this.
'(prelude/connect-to www.google.com 80)
'(send-line GET / HTTP/1.1)
'(send-line Host: www.google.com)
'(send-line)
'(loop read until eof)
'(exit)
Now I don't know how to proceed. I think I must define a macro
prelude/connect-to. For example
(prelude/connect-to www.google.com 80)
should expand to
(begin
(require racket/tcp)
(require racket/port)
(define-values (input-port output-port)
(tcp-connect "www.google.com" 80))))
Here's what I tried. (See my full code at http://pasterack.org/pastes/16943
)
(define-macro (prelude/connect-to HOST PORT)
#'(begin
(require racket/tcp)
(require racket/port)
(define-values (input-port output-port)
(tcp-connect HOST PORT))))
This doesn't work because I get the error message
www.google.com: unbound identifier in module in: www.google.com
This must be because www.google.com is not a string. I don't know how to
turn into a string and this must mean I'm very confused. What should my
macro do so I'd get the desired expansion?
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