(define l1
    (list "See" "ee " "e S" " Sp" "Spo" "pot" "ot " "t r" " ru" "run" "un."))

(define al1
    '((" ca" 1) (" ha" 1) (" in" 1) (" th" 1) ("The" 1) ("at " 1)
      ("at." 1) ("cat" 1) ("e c" 1) ("e h" 1) ("hat" 1) ("he " 2)
      ("in " 1) ("n t" 1) ("t i" 1) ("the" 1))
    ((" th" 34) ("the" 20) ("at " 18) ("hat" 15) ("ed " 13) 
     ("her" 13) ("tha" 13) (" de" 12) ("he " 11) ("re " 11)))

;; DATA DEFINITION
;; A path-string is one of:
;;  - A path
;;  - A string

;; directory-names : path-string -> (listof string)
;; list the names in the given directory, in alphabetical order

;; build-path : path-string path-string -> path
;; create a path by combining parts using the native notation

;; comp50-path : path-string -> string
;; return the full path of a file relative to a comp50 collection

;; basename : path-string -> string
;; returns the last name in a given path

;; DATA DEFINITION
;; A `1string` is a string of length exactly 1

;; read-1bytes : path-string -> (listof 1string)
;; return the contents of a given file, interpreted as bytes

;; geturl-1bytes : string -> (listof 1string)
;; produce the list of bytes served by the given URL, which must be good

;; DATA DEFINITION
;; An sx is one of:
;;   - A string
;;   - A number
;;   - A symbol
;;   - A (listof sx)

;; write-file-sexp : string sx -> string
;; write the given S-expression to the given named file, returning the file's name

;; read-file-sexp : string -> sx
;; read the given S-expression from the file of the given pathname

#|
> (directory-names (comp50-path "language-test"))
(list "abcxyz")
> (directory-names (comp50-path "tiny-language-training"))
(list "English" "French" "German" "Polish")
> (directory-names (comp50-path "language-training"))
(list
 "Czech"
 "English"
 "French"
 "German"
 "Hungarian"
 "Italian"
 "Polish"
 "Spanish")
> (read-1bytes (comp50-path (build-path "language-test" "abcxyz")))
(list "a" "b" "c" "x" "y" "z")
> (geturl-1bytes "http://www.cs.tufts.edu/comp/50/nothing.txt")
(list "N" "o" "t" "h" "i" "n" "g" "'" "s" " " "h" "e" "r" "e" "." "\n")
> (basename "/home/nr/.profile")
".profile"
> (basename "/comp/50/www/homework")
"homework"
> (write-file-sexp "/tmp/test.rktd" '(An S-exp ("string" 7 9)))
"/tmp/test.rktd"
> (read-file-sexp "/tmp/test.rktd")
(list 'An 'S-exp (list "string" 7 9))
> (write-file-sexp "/tmp/image.rktd" (circle 5 "solid" "black"))
write-file-sexp: expects a S-expression as second argument, given #<image>
> 
|#


(define log-10/10 (/ (log 10) 10))

;; log-decibans : number -> number
;; return the 10 times the base-10 logarithm of the given number
(define (log-decibans x)
  (/ (log x) log-10/10))

(check-within (log-decibans 1)      0 EPSILON)
(check-within (log-decibans 10)    10 EPSILON)
(check-within (log-decibans 100)   20 EPSILON)
(check-within (log-decibans 1/10) -10 EPSILON)

(define sample
    '(("English"   #i-124879.38840876492)
      ("German"    #i-136502.98974519692)
      ("French"    #i-138755.4804011435)
      ("Spanish"   #i-140403.25530245638)
      ("Italian"   #i-140643.53502622052)
      ("Hungarian" #i-141477.80928918015)
      ("Czech"     #i-142751.49331737417)
      ("Polish"    #i-143355.53183452427)
      ("Unknown"   #i-156920.91613972152))
)

(define sample2
    '(("English"   #i0.36898273367830303)
      ("German"    #i0.25326695630096535)
      ("French"    #i0.24965274414918953)
      ("Italian"   #i0.24356957546717814)
      ("Spanish"   #i0.24140594907631213)
      ("Polish"    #i0.2054360930761648)
      ("Czech"     #i0.19650868079989064)
      ("Hungarian" #i0.19644545018071768)
      ("Unknown"   #i0.007751224544134543))
)

(define sample3
  '(("English" #i-258080.31739165334)
  ("French"  #i-259023.08641358386)
  ("Spanish" #i-270013.69208337733)
  ("German"  #i-271836.10062956245)
  ("Italian" #i-273627.51560851745)
  ("Hungarian" #i-281419.25852654263)
  ("Czech"   #i-281716.0129245808)
  ("Polish"  #i-284114.33976111293)
  ("Unknown" #i-307050.5955772443))
)