src/HOL/Tools/string_code.ML

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/HOL/Tools/string_code.ML	Wed May 06 19:09:31 2009 +0200
@@ -0,0 +1,88 @@
+(* Author: Florian Haftmann, TU Muenchen
+
+Code generation for character and string literals.
+*)
+
+signature STRING_CODE =
+sig
+  val add_literal_list_string: string -> theory -> theory
+  val add_literal_char: string -> theory -> theory
+  val add_literal_message: string -> theory -> theory
+end;
+
+structure String_Code : STRING_CODE =
+struct
+
+open Basic_Code_Thingol;
+
+fun decode_char nibbles' tt =
+  let
+    fun idx c = find_index (curry (op =) c) nibbles';
+    fun decode ~1 _ = NONE
+      | decode _ ~1 = NONE
+      | decode n m = SOME (chr (n * 16 + m));
+  in case tt
+   of (IConst (c1, _), IConst (c2, _)) => decode (idx c1) (idx c2)
+    | _ => NONE
+  end;
+   
+fun implode_string char' nibbles' mk_char mk_string ts =
+  let
+    fun implode_char (IConst (c, _) `$ t1 `$ t2) =
+          if c = char' then decode_char nibbles' (t1, t2) else NONE
+      | implode_char _ = NONE;
+    val ts' = map_filter implode_char ts;
+  in if length ts = length ts'
+    then (SOME o Code_Printer.str o mk_string o implode) ts'
+    else NONE
+  end;
+
+val cs_nibbles = [@{const_name Nibble0}, @{const_name Nibble1},
+  @{const_name Nibble2}, @{const_name Nibble3},
+  @{const_name Nibble4}, @{const_name Nibble5},
+  @{const_name Nibble6}, @{const_name Nibble7},
+  @{const_name Nibble8}, @{const_name Nibble9},
+  @{const_name NibbleA}, @{const_name NibbleB},
+  @{const_name NibbleC}, @{const_name NibbleD},
+  @{const_name NibbleE}, @{const_name NibbleF}];
+val cs_summa = [@{const_name Nil}, @{const_name Cons}, @{const_name Char}] @ cs_nibbles;
+
+fun add_literal_list_string target =
+  let
+    fun pretty literals (nil' :: cons' :: char' :: nibbles') pr thm vars fxy [(t1, _), (t2, _)] =
+      case Option.map (cons t1) (List_Code.implode_list nil' cons' t2)
+       of SOME ts => (case implode_string char' nibbles'
+          (Code_Printer.literal_char literals) (Code_Printer.literal_string literals) ts
+             of SOME p => p
+              | NONE =>
+                  Code_Printer.literal_list literals (map (pr vars Code_Printer.NOBR) ts))
+        | NONE =>
+            List_Code.default_list (Code_Printer.infix_cons literals) (pr vars) fxy t1 t2;
+  in Code_Target.add_syntax_const target
+    @{const_name Cons} (SOME (2, (cs_summa, pretty)))
+  end;
+
+fun add_literal_char target =
+  let
+    fun pretty literals nibbles' _ thm _ _ [(t1, _), (t2, _)] =
+      case decode_char nibbles' (t1, t2)
+       of SOME c => (Code_Printer.str o Code_Printer.literal_char literals) c
+        | NONE => Code_Printer.nerror thm "Illegal character expression";
+  in Code_Target.add_syntax_const target
+    @{const_name Char} (SOME (2, (cs_nibbles, pretty)))
+  end;
+
+fun add_literal_message target =
+  let
+    fun pretty literals (nil' :: cons' :: char' :: nibbles') _ thm _ _ [(t, _)] =
+      case List_Code.implode_list nil' cons' t
+       of SOME ts => (case implode_string char' nibbles'
+          (Code_Printer.literal_char literals) (Code_Printer.literal_string literals) ts
+             of SOME p => p
+              | NONE => Code_Printer.nerror thm "Illegal message expression")
+        | NONE => Code_Printer.nerror thm "Illegal message expression";
+  in Code_Target.add_syntax_const target 
+    @{const_name STR} (SOME (1, (cs_summa, pretty)))
+  end;
+
+end;