32 lines
835 B
Scheme
32 lines
835 B
Scheme
#lang scheme/base
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(require htdp/error)
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(define (read-file f)
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(check-arg 'read-file (string? f) "string" "first" f)
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(check-arg 'read-file (file-exists? f) "name of file in program's folder" "first" f)
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(list->string
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(with-input-from-file f
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(lambda ()
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(let loop ()
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(define nxt (read-char))
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(if (eof-object? nxt) '() (cons nxt (loop))))))))
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(define (write-file f str)
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(check-arg 'read-file (string? f) "string" "first" f)
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(let ([result (not (file-exists? f))])
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(with-output-to-file f
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(lambda () (printf "~a" str))
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#:exists 'truncate)
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result))
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(provide
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read-file ;; String -> String
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;; read the file f (in current-directory) as a string
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write-file ;; String String -> Boolean
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;; write str to file f (in current-directory);
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;; false, if f exists
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;; true, if f doesn't exist
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)
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