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one more reader, plus shortened the names of the functions

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This commit is contained in:
Matthias Felleisen 2010-04-16 10:49:21 -04:00
parent da312ac680
commit a2af09a445
3 changed files with 72 additions and 52 deletions
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50
collects/2htdp/batch-io.ss
View File

@ -11,28 +11,31 @@
;; -- f must be a file name (string) in the same folder as the program
read-file ;; String -> String
;; read the file f as a string
;; read the specified file as a string
read-file-as-lines ;; String -> [Listof String]
;; read the file f as a list of strings, one per line
read-as-1strings ;; String -> [Listof 1String]
;; read the specified file as a list of 1strings (characters)
read-file-as-words ;; String -> [Listof String]
;; read the file f as a list of white-space separated tokens
read-as-lines ;; String -> [Listof String]
;; read the specified file as a list of strings, one per line
read-file-as-1strings ;; String -> [Listof 1String]
;; read the file f as a list of 1strings (characters)
read-as-words ;; String -> [Listof String]
;; read the specified file as a list of white-space separated tokens
read-file-as-csv ;; String -> [Listof [Listof (U Any)]]
read-as-words/line ;; String -> [Listof [Listof String]]
;; read the specified file as a list of lines, each line as a list of words
read-as-csv ;; String -> [Listof [Listof (U Any)]]
;; -- f must be formated as a a file with comma-separated values (Any)
;; read the file f as a list of lists---one per line---of values (Any)
;; read the specified file as a list of lists---one per line---of values (Any)
read-file-as-csv/rows ;; String ([Listof Any] -> X) -> [Listof X]
read-as-csv/rows ;; String ([Listof Any] -> X) -> [Listof X]
;; -- f must be formated as a a file with comma-separated values (Any)
;; read the file f as a file of comma-separated values, apply the second
;; read the specified file as a file of comma-separated values, apply the second
;; argument to each row, i.e., list of CSV on one line
write-file ;; String String -> Boolean
;; write the second argument to file f in the same folder as the program
;; write the second argument to specified file in the same folder as the program
;; produce false, if f exists
;; produce true, if f doesn't exist
)
@ -51,22 +54,27 @@
(def-reader (read-file f)
(list->string (read-chunks f read-char drop-last-newline)))
(def-reader (read-file-as-1strings f)
(def-reader (read-as-1strings f)
(map string (read-chunks f read-char drop-last-newline)))
(def-reader (read-file-as-lines f)
(def-reader (read-as-lines f)
(read-chunks f read-line reverse))
(def-reader (read-file-as-words f)
(def-reader (read-as-words f)
(define lines (read-chunks f read-line reverse))
(foldr (lambda (f r) (append (split f) r)) '() lines))
(def-reader (read-file-as-csv f)
(read-file-as-csv/func f))
(def-reader (read-as-words/line f)
;; String -> [Listof [Listof String]]
;; read the specified file as a list of lines, each line as a list of words
(map split (read-chunks f read-line reverse)))
(def-reader (read-file-as-csv/rows f row)
(check-proc 'read-file-as-cvs row 1 "one argument" "row")
(read-file-as-csv/func f row))
(def-reader (read-as-csv f)
(read-as-csv/func f))
(def-reader (read-as-csv/rows f row)
(check-proc 'read-as-cvs row 1 "one argument" "row")
(read-as-csv/func f row))
;; -----------------------------------------------------------------------------
;; writer
@ -84,7 +92,7 @@
;; auxiliaries
;; String [([Listof X] -> Y)] -> [Listof Y]
(define (read-file-as-csv/func f [row (lambda (x) x)])
(define (read-as-csv/func f [row (lambda (x) x)])
(local ((define (reader o)
(make-csv-reader o '((strip-leading-whitespace? . #t)
(strip-trailing-whitespace? . #t)))))

29
collects/2htdp/tests/batch-io.ss
View File

@ -25,14 +25,14 @@ eos
(check-true (string=? (read-file file) test2) "read-file 2")
(write-file file test1)
(check-equal? (read-file-as-lines file) (list test1) "as-lines 1")
(check-equal? (read-as-lines file) (list test1) "as-lines 1")
(write-file file test2)
(check-equal? (read-file-as-lines file) test2-as-list "as-lines 2")
(check-equal? (read-as-lines file) test2-as-list "as-lines 2")
(define as-1strings1 (map string (string->list test1)))
(write-file file test1)
(check-equal? (read-file-as-1strings file) as-1strings1 "as-1strings 1")
(check-equal? (read-as-1strings file) as-1strings1 "as-1strings 1")
(define as-1strings2
(map string
@ -43,7 +43,7 @@ eos
test2-as-list))))))
(write-file file test2)
(check-equal? (read-file-as-1strings file) as-1strings2 "as-lines 2")
(check-equal? (read-as-1strings file) as-1strings2 "as-lines 2")
(define test3 #<< eos
word1, word2
@ -52,12 +52,15 @@ eos
)
(write-file file test3)
(check-equal? (read-file-as-csv file) '(("word1" "word2") ("word3" "word4"))
"as-cvs 1")
(check-equal? (read-file-as-csv/rows file length) '(2 2)
"as-words/rows")
(check-equal? (read-file-as-words file) '("word1," "word2" "word3," "word4")
(check-equal? (read-as-words file) '("word1," "word2" "word3," "word4")
"as-words")
(check-equal? (read-as-words/line file) '(("word1," "word2") ("word3," "word4"))
"as-words")
(check-equal? (read-as-csv file) '(("word1" "word2") ("word3" "word4"))
"as-cvs 1")
(check-equal? (read-as-csv/rows file length) '(2 2)
"as-words/rows")
(check-exn exn:fail:contract? (lambda () (write-file 0 1)))
(check-exn exn:fail:contract? (lambda () (write-file '("test") 1)))
@ -66,8 +69,8 @@ eos
(check-exn exn:fail:contract? (lambda () (read-file 0)))
(check-exn exn:fail:contract? (lambda () (read-file '("test"))))
(check-exn exn:fail:contract? (lambda () (read-file-as-lines 0)))
(check-exn exn:fail:contract? (lambda () (read-file-as-lines '("test"))))
(check-exn exn:fail:contract? (lambda () (read-as-lines 0)))
(check-exn exn:fail:contract? (lambda () (read-as-lines '("test"))))
(check-exn exn:fail:contract? (lambda () (read-file-as-1strings 0)))
(check-exn exn:fail:contract? (lambda () (read-file-as-1strings '("test"))))
(check-exn exn:fail:contract? (lambda () (read-as-1strings 0)))
(check-exn exn:fail:contract? (lambda () (read-as-1strings '("test"))))

39
collects/teachpack/2htdp/scribblings/batch-io.scrbl
View File

@ -56,36 +56,45 @@ assuming the file named @scheme["data.txt"] has this shape:
Note how the leading space in the second line translates into the space
between the newline indicator and the word @scheme["good"] in the result.}
@item{@reading[read-file-as-lines (listof string?)]{a list of strings, one per line}
@item{@reading[read-as-1strings (listof 1string?)]{a list of one-char strings, one per character}
@examples[#:eval (examples-batch-io)
(read-file-as-lines "data.txt")
(read-as-1strings "data.txt")
]
Note how this function reproduces all parts of the file faithfully,
including spaces and newlines.}
@item{@reading[read-as-lines (listof string?)]{a list of strings, one per line}
@examples[#:eval (examples-batch-io)
(read-as-lines "data.txt")
]
when @scheme["data.txt"] is the name of the same file as in the preceding
item. And again, the leading space of the second line shows up in the
second string in the list.}
@item{@reading[read-file-as-words (listof string?)]{a list of strings, one per white-space separated token in the file}
@item{@reading[read-as-words (listof string?)]{a list of strings, one per white-space separated token in the file}
@examples[#:eval (examples-batch-io)
(read-file-as-words "data.txt")
(read-as-words "data.txt")
]
This time, however, the extra leading space of the second line of
@scheme["data.txt"] has disappeared in the result. The space is considered
a part of the separator that surrounds the word @scheme["good"].
}
@item{@reading[read-file-as-1strings (listof 1string?)]{a list of one-char strings, one per character}
@item{@reading[read-as-words/line (listof string?)]{a list of lists, one per line; each line is represented as a list of white-space separated tokens}
@examples[#:eval (examples-batch-io)
(read-file-as-1strings "data.txt")
(read-as-words/line "data.txt")
]
Note how this function reproduces all parts of the file faithfully,
including spaces and newlines.}
The results is similar to the one that @scheme[read-as-words] produces,
except that the organization of the file into lines is preserved.
}
@item{@reading[read-file-as-csv (listof (listof any/c))]{a list of lists of comma-separated values}
@item{@reading[read-as-csv (listof (listof any/c))]{a list of lists of comma-separated values}
@examples[#:eval (examples-batch-io)
(read-file-as-csv "data.csv")
(read-as-csv "data.csv")
]
where the file named @scheme["data.csv"] has this shape:
@(file-is "data.csv")
@ -94,16 +103,16 @@ length. Here the third line of the file turns into a row of three
elements.
}
@item{@defproc[(@read-file-as-csv/rows [f (and/c string? file-exists?)][s
@item{@defproc[(@read-as-csv/rows [f (and/c string? exists?)][s
(-> (listof any/c) X?)]) (listof X?)]{reads the content of file @scheme[f] and
produces it as list of rows, each constructed via @scheme[s]}
@examples[#:eval (examples-batch-io)
(read-file-as-csv/rows "data.csv" (lambda (x) x))
(read-file-as-csv/rows "data.csv" length)
(read-as-csv/rows "data.csv" (lambda (x) x))
(read-as-csv/rows "data.csv" length)
]
The first example shows how @scheme[read-file-as-csv] is just a short form
for @scheme[read-file-as-csv/rows]; the second one simply counts the
The first example shows how @scheme[read-as-csv] is just a short form
for @scheme[read-as-csv/rows]; the second one simply counts the
number of separated tokens and the result is just a list of numbers.
In many cases, the function argument is used to construct a structure from
a row.}