대화형 모드의 진법(radix) 변환 예제 with F#

다음은  대화형 모드(interactive mode)에서 진법 변환(radix conversion)하는 F# 소스 코드이다.

   주: 이 소스는 Python 용으로 만들어 둔 소스를 F# 언어로 바꾼 것이라서
        F# 언어의 명령형 언어 특징을 위주로 짜여져 있다.

메뉴는 주메뉴 Command: (S)et radix, (A)bout, (Q)uit or E(x)it
와 부메뉴 SubCommand: 'main()' to goto Main menu, 'exit()' or 'quit()' to exit
로 구성되어 있으며, 진법 변환의 핵심은 소스 코드에 자체 작성된 함수 atoi(string, radix)와  itoa(number, radix)의 사용이다.

         let value = atoi(str, srcRdx)
         let str = itoa(value, destRdx)

지원되는 진법은 2진법에서 36진법까지이다.

1. (*
2.  *  Filename: ConvertRadix.fs
3.  *            Convert radix in an interactive mode.
4.  *
5.  *  Compile: fsc convertRadix.fs
6.  *  Execute: ConvertRadix
7.  *
8.  *      Date:  2010/07/14
9.  *    Author:  PH Kim   [ pkim (AT) scripts.pe.kr ]
10.  *)
12. #light
14. exception RuntimeError of string
15. exception ValueError of string
17. let println s =
18.     printfn "%O" s
20. let print s =
21.     printf "%O" s
23. let printUsage dummy =
24.     println "Usage: python convertRadix.py"
25.     println "Convert radix in a interactive mode, where the maximum radix is 36."
27. let printAbout dummy =
28.     println "    About: Convert radix in a interactive mode."
30. let printMainMenu dummy =
31.     println "  Command: (S)et radix, (A)bout, (Q)uit or E(x)it"
33. let printMainPrompt dummy =
34.     print "  Prompt> "
36. let printSubMenu srcRadix destRadix =
37.     println ("    Convert Radix_" + (sprintf "%O" srcRadix) + " to Radix_" + (sprintf "%O" DestRadix) )
38.     println ("    SubCommand: 'main()' to goto Main menu, 'exit()' or 'quit()' to exit" )
40. let printSubPrompt dummy =
41.     print "    Input Value>> "
43. let BASE36 = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"
45. let itoa (num : int, radix : int) =
46.    let mutable isNegative = false
47.    let mutable numx = num
48.    if num < 0 then
49.       isNegative <- true
50.       numx <- (-num)
52.    let mutable arr = [  ]
53.    let mutable q = numx
54.    let mutable r = 0
56.    while (q >= radix) do
57.        r <- int (q % radix)
58.        q <- int (q / radix)
59.        arr <- List.append arr [ sprintf "%O" (BASE36.[r]) ]
61.    arr <- List.append arr [ sprintf "%O" (BASE36.[q]) ]
62.    if isNegative then
63.       arr <- List.append arr [ "-" ]
65.    arr <- List.rev arr
66.    System.String.Join("", List.toArray arr)
68. let atoi (s : string, radix : int) : int =
69.     let mutable ret = 0
70.     let mutable isNegative = false
71.     let len = s.Length
72.     let mutable valx = 0
73.     let mutable c = s.[0]
75.     if c = '-' then
76.         isNegative <- true
77.     elif (c >= '0' && c <= '9') then
78.         ret <- (int c) - (int '0')
79.     elif (c >= 'A' && c <= 'Z') then
80.         ret <- int c - int 'A' + 10
81.     elif (c >= 'a' && c <= 'z') then
82.         ret <- int c - int 'a' + 10
83.     if (ret >= radix) then
84.         printfn "    Error: Can not read \"%s\" (as radix %d): %O is an invalid character!" s radix ret
86.     for i = 1 to len - 1 do
87.         c <- s.[i]
88.         ret <- ret*radix
89.         if (c >= '0' && c <= '9') then
90.             valx <- int c - int '0'
91.         elif (c >= 'A' && c <= 'Z') then
92.             valx <- int c - int 'A' + 10
93.         elif (c >= 'a' && c <= 'z') then
94.             valx <- int c - int 'a' + 10
95.         if (valx >= radix) then
96.             printfn "    Error: Can not read \"%s\" (as radix %d): %O is an invalid character!" s radix c
97.         ret <- ret + valx
99.     if (isNegative) then
100.         ret <- (-ret )
101.     ret
103. let convertRadix s srcRdx destRdx =
104.     let mutable ret = ""
105.     try
106.         try
107.             let valx = atoi (s, srcRdx)
108.             ret <- itoa (valx, destRdx)
109.             ret <- ret.ToUpper()
110.             ret
111.         with
112.             | ValueError e -> printfn "    Error: Cannot convert radix %O" srcRdx
113.                               ret <- "????"
114.                               ret
115.     finally
116.         ret.ToUpper() |> ignore
118. let doConvert srcRadix destRadix =
119.     let mutable line = ""
120.     let mutable cmd = ""
121.     let mutable srcStr = ""
122.     let mutable destStr = ""
123.     printfn ""
125.     printSubMenu srcRadix  destRadix
126.     let mutable stop_flag = false
127.     try
128.         while not stop_flag do
129.             printSubPrompt()
130.             let mutable cmd = System.Console.ReadLine()
131.             while (String.length cmd) = 0 do
132.                 cmd <- System.Console.ReadLine()
134.             if "main()" = cmd then
135.                 stop_flag <- false
136.                 raise (RuntimeError ("return to main menu"))
137.             elif "exit()" = cmd || "quit()" = cmd then
138.                 exit(0)
140.             try
141.                 let dum = atoi(cmd, srcRadix) |> ignore
142.                 srcStr <- cmd
143.                 destStr <- (convertRadix srcStr srcRadix destRadix)
144.                 printfn "        ( %s )_%d   --->   ( %s )_%d" srcStr srcRadix destStr destRadix
145.                 printfn ""
146.             with
147.                 | ValueError e -> println ""
148.     with
149.         | RuntimeError e -> printfn "      %O" e
151. let doStart dummy =
152.     let mutable line = ""
153.     let mutable cmd = ""
154.     let mutable srcRadix = 10
155.     let mutable destRadix = 10
156.     let mutable srcStr = ""
157.     let mutable destStr = ""
158.     let mutable onlyOnce = true
159.     let mutable st = [| |]
161.     try
162.         while true do
163.             printfn ""
164.             if onlyOnce then
165.                 println "  The supported maximum radix is 36."
166.                 onlyOnce <- false
168.             printMainMenu 0
169.             printMainPrompt 0
171.             cmd <- System.Console.ReadLine()
172.             while (String.length cmd) = 0 do
173.                 cmd <- System.Console.ReadLine()
175.             if "qQxX".IndexOf(cmd) >= 0 && (String.length cmd) = 1 then
176.                 exit(0)
177.             elif "aA".IndexOf(cmd) >= 0 && cmd.Length = 1 then
178.                 printAbout 0
179.             elif "sS".IndexOf(cmd) >= 0 && cmd.Length = 1 then
180.                 print "  Input the source and target radices (say, 16 2): "
181.                 line <- System.Console.ReadLine()
182.                 st <- line.Split [| ' ' |]
184.                 while (Array.length st) < 2 do
185.                     print ("  Input the source and target radices (say, 16 2): ")
186.                     line <- System.Console.ReadLine()
187.                     st <- line.Split [| ' ' |]
189.                 srcRadix <- int (st.[0])
190.                 destRadix <- int (st.[1])
191.                 doConvert srcRadix destRadix
192.     with
193.         | RuntimeError e ->  printfn "  Error foune!!"
195. // Begin here
196. let cmdArgs = System.Environment.GetCommandLineArgs()
197. if (Array.length cmdArgs > 1 && "-h" = cmdArgs.[1]) then
198.     printUsage 0
199.     exit(1)
201. doStart 0 |> ignore

컴파일> fsc ConvertRadix.fs

실행> ConvertRadix

  The supported maximum radix is 36.
  Command: (S)et radix, (A)bout, (Q)uit or E(x)it
  Prompt> s
  Input the source and target radices (say, 16 2): 10 8

    Convert Radix_10 to Radix_8
    SubCommand: 'main()' to goto Main menu, 'exit()' or 'quit()' to exit
    Input Value>> 200
        ( 200 )_10   --->   ( 310 )_8

    Input Value>> main()

  Command: (S)et radix, (A)bout, (Q)uit or E(x)it
  Prompt> S
  Input the source and target radices (say, 16 2): 8 10

    Convert Radix_8 to Radix_10
    SubCommand: 'main()' to goto Main menu, 'exit()' or 'quit()' to exit
    Input Value>> 2666
        ( 2666 )_8   --->   ( 1462 )_10

    Input Value>> main()

  Command: (S)et radix, (A)bout, (Q)uit or E(x)it
  Prompt> x