racket/collects/scribblings/guide/contracts-utils.rkt
Robby Findler 17a723a63e Improve the contract error messages:
- add context information, so we can see which part of the contract failed
 - re-arrange some of the information in the contracts
2012-04-21 16:55:03 -05:00

77 lines
2.6 KiB
Racket

#lang racket
(require scribble/basic
(for-syntax racket/port)
racket/include
scribble/eval
(except-in scribble/manual link))
(provide ctc-section
ctc-link
exercise
solution
external-file
contract-eval)
(define (ctc-section #:tag [tag #f] . rest)
(keyword-apply section
'(#:tag)
(list (and tag (str->tag tag)))
rest))
(define (ctc-link tag . rest) (apply seclink (str->tag tag) rest))
(define (str->tag tag) (format "contracts-~a" tag))
(define exercise-number 0)
(define (exercise)
(set! exercise-number (+ exercise-number 1))
(bold (format "Exercise ~a" exercise-number)))
(define (solution)
(bold (format "Solution to exercise ~a" exercise-number)))
#;
(define-syntax (external-file stx)
(syntax-case stx ()
[(_ filename)
(call-with-input-file (build-path "contracts-examples" (format "~a.rkt" (syntax-e #'filename)))
(λ (port)
(define prefix "#reader scribble/comment-reader\n[racketmod\nracket\n")
(define suffix "]")
(with-syntax ([s (parameterize ([read-accept-reader #t])
(read-syntax 'contract-examples
(input-port-append #f
(open-input-string prefix)
port
(open-input-string suffix))))])
#'s)))]))
(require (for-syntax (only-in scribble/comment-reader [read-syntax comment-reader])))
(define-for-syntax (comment-racketmod-reader path port)
(let ([pb (peek-byte port)])
(if (eof-object? pb)
pb
(let ([m (regexp-match #rx"^#lang " port)])
(unless m
(raise-syntax-error 'comment-racket-reader "expected a #lang to begin file ~s" path))
(let ([np (let-values ([(line col pos) (port-next-location port)])
(relocate-input-port port line 0 pos))])
(port-count-lines! np)
(let loop ([objects '()])
(let ([next (comment-reader path np)])
(cond
[(eof-object? next)
#`(racketmod #,@(reverse objects))]
[else
(loop (cons next objects))]))))))))
(define-syntax (external-file stx)
(syntax-case stx ()
[(_ filename)
#`(include/reader #,(format "contracts-examples/~a.rkt" (syntax-e #'filename))
comment-racketmod-reader)]))
(define contract-eval (make-base-eval))
(contract-eval '(require racket/contract))