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1 (* Title: HOL/String.thy |
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2 ID: $Id$ |
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3 |
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4 Hex chars. Strings. |
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5 *) |
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6 |
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7 String = List + |
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8 |
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9 datatype |
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10 nibble = H00 | H01 | H02 | H03 | H04 | H05 | H06 | H07 |
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11 | H08 | H09 | H0A | H0B | H0C | H0D | H0E | H0F |
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12 |
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13 datatype |
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14 char = Char (nibble, nibble) |
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15 |
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16 types |
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17 string = "char list" |
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18 |
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19 syntax |
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20 "_Char" :: "xstr => char" ("CHR _") |
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21 "_String" :: "xstr => string" ("_") |
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22 |
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23 end |
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24 |
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25 |
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26 ML |
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27 |
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28 local |
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29 open Syntax; |
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30 |
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31 val ssquote = enclose "''" "''"; |
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32 |
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33 |
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34 (* chars *) |
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35 |
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36 val zero = ord "0"; |
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37 val ten = ord "A" - 10; |
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38 |
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39 fun mk_nib n = |
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40 const ("H0" ^ chr (n + (if n <= 9 then zero else ten))); |
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41 |
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42 fun dest_nib (Const (c, _)) = |
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43 (case explode c of |
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44 ["H", "0", h] => ord h - (if h <= "9" then zero else ten) |
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45 | _ => raise Match) |
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46 | dest_nib _ = raise Match; |
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47 |
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48 fun dest_nibs t1 t2 = chr (dest_nib t1 * 16 + dest_nib t2); |
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49 |
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50 |
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51 fun mk_char c = |
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52 const "Char" $ mk_nib (ord c div 16) $ mk_nib (ord c mod 16); |
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53 |
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54 fun dest_char (Const ("Char", _) $ t1 $ t2) = dest_nibs t1 t2 |
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55 | dest_char _ = raise Match; |
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56 |
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57 |
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58 fun char_tr (*"_Char"*) [Free (c, _)] = |
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59 if size c = 1 then mk_char c |
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60 else error ("Bad character: " ^ quote c) |
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61 | char_tr (*"_Char"*) ts = raise_term "char_tr" ts; |
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62 |
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63 fun char_tr' (*"Char"*) [t1, t2] = |
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64 const "_Char" $ free (ssquote (dest_nibs t1 t2)) |
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65 | char_tr' (*"Char"*) _ = raise Match; |
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66 |
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67 |
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68 (* strings *) |
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69 |
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70 fun mk_string [] = const constrainC $ const "[]" $ const "string" |
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71 | mk_string (t :: ts) = const "op #" $ t $ mk_string ts; |
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72 |
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73 fun dest_string (Const ("[]", _)) = [] |
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74 | dest_string (Const ("op #", _) $ c $ cs) = dest_char c :: dest_string cs |
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75 | dest_string _ = raise Match; |
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76 |
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77 |
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78 fun string_tr (*"_String"*) [Free (txt, _)] = |
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79 mk_string (map mk_char (explode txt)) |
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80 | string_tr (*"_String"*) ts = raise_term "string_tr" ts; |
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81 |
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82 fun cons_tr' (*"op #"*) [c, cs] = |
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83 const "_String" $ free (ssquote (implode (dest_char c :: dest_string cs))) |
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84 | cons_tr' (*"op #"*) ts = raise Match; |
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85 |
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86 in |
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87 val parse_translation = [("_Char", char_tr), ("_String", string_tr)]; |
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88 val print_translation = [("Char", char_tr'), ("op #", cons_tr')]; |
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89 end; |
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90 |