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+;;; 6.945 Problem Set #1 - workfile
+;;; 02/10/2009
+;;; Bryan Newbold <bnewbold@mit.edu>
+
+(load "regexp.scm")
+
+
+(pp (r:grep (r:seq " "
+ (r:repeat 3 5 (r:alt (r:quote "cat") (r:quote "dog")))
+ (r:eol))
+ "tests.txt"))
+
+;-------------------------------------------------------------------
+; 1.1: define r:* and r:+
+
+(define (r:+ pattern)
+ (r:repeat 1 #f pattern))
+
+(define (r:* pattern)
+ (r:repeat 0 #f pattern))
+
+(pp (r:grep (r:seq (r:quote "dog")
+ (r:+ (r:quote "cat")))
+ "tests.txt"))
+
+;("[09]. catdogcat" "[11]. dogdogcatdogdog" "[13]. acatdogdogcats")
+
+(pp (r:grep (r:seq (r:quote "cat")
+ (r:+ (r:char-from (string->char-set "ogd")))
+ (r:quote "cat"))
+ "tests.txt"))
+
+;("[09]. catdogcat" "[13]. acatdogdogcats")
+
+(pp (r:grep (r:seq " "
+ (r:+ (r:quote "cat"))
+ (r:eol))
+ "tests.txt"))
+; #f
+
+(pp (r:grep (r:* (r:quote "something that isn't there"))
+ "tests.txt"))
+; matches all
+
+(pp (r:grep (r:repeat 2 3 (r:* (r:char-from (string->char-set "tca"))))
+ "tests.txt"))
+; matches all: nothing repeated several times
+
+(pp (r:grep (r:seq (r:quote "dog")
+ (r:+ (r:quote "cat"))
+ (r:quote "dog"))
+ "tests.txt"))
+
+;("[11]. dogdogcatdogdog")
+
+(pp (r:grep (r:seq (r:quote "dog")
+ (r:* (r:quote "cat"))
+ (r:quote "dog"))
+ "tests.txt"))
+#|
+("[10]. catcatdogdog" "[11]. dogdogcatdogdog"
+ "[12]. catcatcatdogdogdog"
+ "[13]. acatdogdogcats"
+ "[14]. ifacatdogdogs"
+ "[15]. acatdogdogsme")
+|#
+
+;-------------------------------------------------------------------------
+; 1.2
+
+(define (r:repeat min max expr)
+ (if (not (exact-nonnegative-integer? min))
+ (error "Min must be non-negative integer:" min))
+ (if max
+ (begin
+ (if (not (exact-nonnegative-integer? max))
+ (error "Max must be non-negative integer (or null):" max))
+ (if (not (<= min max))
+ (error "Min not less than max:" min max))))
+ (cond
+ ((not max) (r:seq expr (string-append "\\{" (number->string min) ",\\}")))
+ ((= max min) (r:seq expr (string-append "\\{" (number->string min) "\\}")))
+ (else (r:seq expr (string-append "\\{"
+ (number->string min)
+ ","
+ (number->string max)
+ "\\}")))))
+#| tests:
+(pp (r:grep (r:repeat 2 3 (r:quote "cat"))
+ "tests.txt"))
+(pp (r:grep (r:repeat 2 #f (r:quote "cat"))
+ "tests.txt"))
+(pp (r:grep (r:repeat 1 1 (r:quote "cat"))
+ "tests.txt"))
+(pp (r:grep (r:repeat 4 3 (r:quote "cat"))
+ "tests.txt"))
+(r:repeat 2 3 (r:quote "cat"))
+|#
+
+;---------------------------------------------------------------------------
+; 1.3
+
+(define (r:subexp . exprs)
+ (string-append "\\(" (apply string-append exprs) "\\)"))
+
+(define (r:seq . exprs)
+ (apply string-append exprs))
+
+(r:seq " " (r:subexp "sdf") "dddd")
+
+(define (r:repeat min max expr)
+ (if (not (exact-nonnegative-integer? min))
+ (error "Min must be non-negative integer:" min))
+ (if max
+ (begin
+ (if (not (exact-nonnegative-integer? max))
+ (error "Max must be non-negative integer (or null):" max))
+ (if (not (<= min max))
+ (error "Min not less than max:" min max))))
+ (cond
+ ((not max) (r:seq (r:subexp expr)
+ (string-append "\\{" (number->string min) ",\\}")))
+ ((= max min) (r:seq (r:subexp expr)
+ (string-append "\\{" (number->string min) "\\}")))
+ (else (r:seq (r:subexp expr)
+ (string-append "\\{"
+ (number->string min)
+ ","
+ (number->string max)
+ "\\}")))))
+
+(define (r:alt . exprs)
+ (if (pair? exprs)
+ (r:subexp (apply r:seq
+ (cons (car exprs)
+ (append-map (lambda (expr)
+ (list "\\|" expr))
+ (cdr exprs)))))
+ (r:seq)))
+
+(r:alt "first thing" "second thing")
+
+;----------------------------------------------------------------------------
+; 1.4
+
+(define (r:backref n)
+ (string-append "\\" (number->string n)))
+
+;----------------------------------------------------------------------------
+; 1.5
+
+; the following are only the expressions which had to be rewritten...
+
+(define (r-grep:seq . exprs)
+ (let ((choose-grep (lambda (x)
+ (cond
+ ((string? x) x)
+ ((list? x) (car x))))))
+ (apply string-append (map choose-grep exprs))))
+
+(r-grep:seq "a" "b" '("grep" "egrep"))
+; abgrep
+
+(define (r-egrep:seq . exprs)
+ (let ((choose-egrep (lambda (x)
+ (cond
+ ((string? x) x)
+ ((list? x) (cadr x))))))
+ (apply string-append (map choose-egrep exprs))))
+
+#| test:
+(r-grep:seq "a" "b" '("grep" "egrep"))
+; "abgrep"
+(r-egrep:seq "a" "b" '("grep" "egrep"))
+; "abegrep"
+|#
+
+(define (r:seq . exprs)
+ (cons (lambda () (apply r-grep:seq exprs))
+ (cons (lambda () (apply r-egrep:seq exprs)) '())))
+
+#| test:
+(r:seq "a" "b" '("grep" "egrep"))
+;Value: (#[compound-procedure 14] #[compound-procedure 15])
+((car (r:seq "a" "b" '("grep" "egrep"))))
+; "abgrep"
+((cadr (r:seq "a" "b" '("grep" "egrep"))))
+; "abegrep"
+|#
+
+(define (r-egrep:alt . exprs)
+ (let ((choose-egrep (lambda (x)
+ (cond
+ ((string? x) x)
+ ((list? x) ((cadr x)))))))
+ (if (pair? exprs)
+ (apply r-egrep:seq
+ (cons (choose-egrep (car exprs))
+ (append-map (lambda (expr)
+ (list "|" (choose-egrep expr)))
+ (cdr exprs))))
+ (r-egrep:seq))))
+
+(define (r-grep:alt . exprs)
+ (let ((choose-grep (lambda (x)
+ (cond
+ ((string? x) x)
+ ((list? x) ((car x)))))))
+ (if (pair? exprs)
+ (apply r-grep:seq
+ (cons (choose-grep (car exprs))
+ (append-map (lambda (expr)
+ (list "\\|" (choose-grep expr)))
+ (cdr exprs))))
+ (r-grep:seq))))
+
+(define (r:alt . exprs)
+ (cons (lambda () (apply r-grep:alt exprs))
+ (cons (lambda () (apply r-egrep:alt exprs)) '())))
+
+#| test:
+(r-egrep:alt "a" (r:dot) "c")
+;Value: "a|.|c"
+(r:alt "asdf" (r:dot))
+;Value: (#[compound-procedure 16] #[compound-procedure 17])
+((car (r:alt "asdf" (r:dot))))
+;Value: "asdf\\|."
+((cadr (r:alt "asdf" (r:dot))))
+;Value: "asdf|."
+|#
+
+(define (r-grep:repeat min max expr)
+ (let ((choose-grep (lambda (x)
+ (cond
+ ((string? x) x)
+ ((list? x) ((car x)))))))
+ (if (not (exact-nonnegative-integer? min))
+ (error "Min must be non-negative integer:" min))
+ (if max
+ (begin
+ (if (not (exact-nonnegative-integer? max))
+ (error "Max must be non-negative integer (or null):" max))
+ (if (not (<= min max))
+ (error "Min not less than max:" min max))))
+ (cond
+ ((not max) (r-grep:seq (r-grep:subexp (choose-grep expr))
+ (string-append "\\{" (number->string min) ",\\}")))
+ ((= max min) (r-grep:seq (r-grep:subexp (choose-grep expr))
+ (string-append "\\{" (number->string min) "\\}")))
+ (else (r-grep:seq (r-grep:subexp (choose-grep expr))
+ (string-append "\\{"
+ (number->string min)
+ ","
+ (number->string max)
+ "\\}"))))))
+
+
+(define (r-egrep:repeat min max expr)
+ (let ((choose-egrep (lambda (x)
+ (cond
+ ((string? x) x)
+ ((list? x) ((cadr x)))))))
+ (if (not (exact-nonnegative-integer? min))
+ (error "Min must be non-negative integer:" min))
+ (if max
+ (begin
+ (if (not (exact-nonnegative-integer? max))
+ (error "Max must be non-negative integer (or null):" max))
+ (if (not (<= min max))
+ (error "Min not less than max:" min max))))
+ (cond
+ ((not max) (r-egrep:seq (r-egrep:subexp (choose-egrep expr))
+ (string-append "{" (number->string min) ",}")))
+ ((= max min) (r-egrep:seq (r-egrep:subexp (choose-egrep expr))
+ (string-append "{" (number->string min) "}")))
+ (else (r-egrep:seq (r-egrep:subexp (choose-egrep expr))
+ (string-append "{"
+ (number->string min)
+ ","
+ (number->string max)
+ "}"))))))
+
+(define (r:repeat min max expr)
+ (cons (lambda () (r-grep:repeat min max expr))
+ (cons (lambda () (r-egrep:repeat min max expr)) '())))
+
+(define (r-grep:subexp . exprs)
+ (string-append "\\(" (apply string-append
+ (map (lambda (x)
+ (cond
+ ((string? x) x)
+ ((pair? x) ((car x)))))
+ exprs)) "\\)"))
+
+(define (r-egrep:subexp . exprs)
+ (string-append "(" (apply string-append
+ (map (lambda (x)
+ (cond
+ ((string? x) x)
+ ((pair? x) ((cadr x)))))
+ exprs)) ")"))
+
+(define (r:subexp . exprs)
+ (cons (lambda () (apply r-grep:subexp exprs))
+ (cons (lambda () (apply r-egrep:subexp exprs)) '())))
+
+#| test:
+(r:subexp "a" "b" (r:dot))
+;Value: (#[compound-procedure 25] #[compound-procedure 26])
+((cadr (r:subexp "a" "b" (r:dot))))
+;Value: "(ab.)"
+((car (r:subexp "a" "b" (r:dot))))
+;Value: "\\(ab.\\)"
+|#
+
+(define (r:grep expr filename)
+ (r:grep-like "grep" '() ((car expr)) filename))
+
+(define (r:egrep expr filename)
+ (if (eq? microcode-id/operating-system 'nt)
+ (r:grep-like "grep" '("-E") ((cadr expr)) filename)
+ (r:grep-like "egrep" '() ((cadr expr)) filename)))
+
+(pp (r:grep (r:seq (r:repeat 2 3 (r:quote "cat")) (r:+ (r:quote "dog")))
+ "tests.txt"))
+
+
+
+
+
+
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