Fix #451: C/C++/Java printer: escape newlines and other special chara…

…cters in String
BNFC · Jul 26, 2023 · 77a432f · 77a432f
1 parent 836162d
commit 77a432f
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Showing 7 changed files with 72 additions and 15 deletions.
diff --git a/source/CHANGELOG.md b/source/CHANGELOG.md
@@ -2,6 +2,7 @@
 
 Unreleased
 
+* C/C++/Java: escape newline etc. when printing `String` literals [[#449](https://github.com/BNFC/bnfc/issues/449)]
 * Haskell/GADT: generated `ComposOp.hs` no longer needs `mtl` library [[#438](https://github.com/BNFC/bnfc/pull/438)]
 * Ocaml: fixed a crash in printer with unbalanced `}` [[#439](https://github.com/BNFC/bnfc/issues/439)]
 * Ocaml: removed superfluous `let rec` in the printers for token categories

diff --git a/source/src/BNFC/Backend/C/CFtoCPrinter.hs b/source/src/BNFC/Backend/C/CFtoCPrinter.hs
@@ -107,6 +107,8 @@ mkHFile cf groups = unlines
     "void shChar(Char c);",
     "void shString(String s);",
     "void shIdent(String s);",
+    "void bufEscapeS(const char *s);",
+    "void bufEscapeC(const char c);",
     "void bufAppendS(const char *s);",
     "void bufAppendC(const char c);",
     "void bufReset(void);",
@@ -199,7 +201,7 @@ mkCFile cf groups = concat
       "void ppString(String s, int i)",
       "{",
       "  bufAppendC('\\\"');",
-      "  bufAppendS(s);",
+      "  bufEscapeS(s);",
       "  bufAppendC('\\\"');",
       "  bufAppendC(' ');",
       "}",
@@ -235,13 +237,13 @@ mkCFile cf groups = concat
       "void shChar(Char c)",
       "{",
       "  bufAppendC('\\'');",
-      "  bufAppendC(c);",
+      "  bufEscapeC(c);",
       "  bufAppendC('\\'');",
       "}",
       "void shString(String s)",
       "{",
       "  bufAppendC('\\\"');",
-      "  bufAppendS(s);",
+      "  bufEscapeS(s);",
       "  bufAppendC('\\\"');",
       "}",
       "void shIdent(String s)",
@@ -257,14 +259,34 @@ mkCFile cf groups = concat
       "void sh" ++ t ++ "(String s)",
       "{",
       "  bufAppendC('\\\"');",
-      "  bufAppendS(s);",
+      "  bufEscapeS(s);",
       "  bufAppendC('\\\"');",
       "}",
       ""
       ] | t <- tokenNames cf
      ]
     footer = unlines
      [
+      "void bufEscapeS(const char *s)",
+      "{",
+      "  while (*s) bufEscapeC(*s++);",
+      "}",
+      "void bufEscapeC(const char c)",
+      "{",
+      "  switch(c)",
+      "  {",
+      "    case '\\f': bufAppendS(\"\\\\f\" ); break;",
+      "    case '\\n': bufAppendS(\"\\\\n\" ); break;",
+      "    case '\\r': bufAppendS(\"\\\\r\" ); break;",
+      "    case '\\t': bufAppendS(\"\\\\t\" ); break;",
+      "    case '\\v': bufAppendS(\"\\\\v\" ); break;",
+      "    case '\\\\': bufAppendS(\"\\\\\\\\\"); break;",
+      "    case '\\'': bufAppendS(\"\\\\'\" ); break;",
+      "    case '\\\"': bufAppendS(\"\\\\\\\"\"); break;",
+      "    default: bufAppendC(c);",
+      "  }",
+      "}",
+      "",
       "void bufAppendS(const char *s)",
       "{",
       "  size_t len = strlen(s);",

diff --git a/source/src/BNFC/Backend/CPP/PrettyPrinter.hs b/source/src/BNFC/Backend/CPP/PrettyPrinter.hs
@@ -114,6 +114,28 @@ mkHFile useStl inPackage cf groups = unlines
     "  char *buf_;",
     "  size_t cur_, buf_size;",
     "",
+    "  void inline bufEscape(const char c)",
+    "  {",
+    "    switch(c)",
+    "    {",
+    "      case '\\f': bufAppend(\"\\\\f\" ); break;",
+    "      case '\\n': bufAppend(\"\\\\n\" ); break;",
+    "      case '\\r': bufAppend(\"\\\\r\" ); break;",
+    "      case '\\t': bufAppend(\"\\\\t\" ); break;",
+    "      case '\\v': bufAppend(\"\\\\v\" ); break;",
+    "      case '\\\\': bufAppend(\"\\\\\\\\\"); break;",
+    "      case '\\'': bufAppend(\"\\\\'\" ); break;",
+    "      case '\\\"': bufAppend(\"\\\\\\\"\"); break;",
+    "      default:   bufAppend(c);",
+    "    }",
+    "  }",
+    "",
+    "  void inline bufEscape(const char *s)",
+    "  {",
+    "    while (*s) bufEscape(*s++);",
+    "  }",
+    "",
+    if useStl then render (nest 2 $ bufAppendString "bufEscape") else "",
     "  void inline bufAppend(const char *s)",
     "  {",
     "    size_t end = cur_ + strlen(s);",
@@ -137,7 +159,7 @@ mkHFile useStl inPackage cf groups = unlines
     "    buf_[++cur_] = 0;",
     "  }",
     "",
-    if useStl then render (nest 2 bufAppendString) else "",
+    if useStl then render (nest 2 $ bufAppendString "bufAppend") else "",
     "  void inline bufReset(void)",
     "  {",
     "    if (buf_) delete[] buf_;",
@@ -160,12 +182,12 @@ mkHFile useStl inPackage cf groups = unlines
     "};",
     ""
    ]
-  bufAppendString :: Doc
-  bufAppendString =
-      "void inline bufAppend(String str)"
+  bufAppendString :: Doc -> Doc
+  bufAppendString f =
+      "void inline" <+> f <> "(String str)"
       $$ codeblock 2
           [ "const char *s = str.c_str();"
-          , "bufAppend(s);"
+          , f <> "(s);"
           ]
   showHeader = unlines
    [
@@ -303,7 +325,7 @@ mkCFile useStl inPackage cf groups = concat
       "void PrintAbsyn::visitString(String s)",
       "{",
       "  bufAppend('\\\"');",
-      "  bufAppend(s);",
+      "  bufEscape(s);",
       "  bufAppend('\\\"');",
       "  bufAppend(' ');",
       "}",
@@ -342,13 +364,13 @@ mkCFile useStl inPackage cf groups = concat
       "void ShowAbsyn::visitChar(Char c)",
       "{",
       "  bufAppend('\\'');",
-      "  bufAppend(c);",
+      "  bufEscape(c);",
       "  bufAppend('\\'');",
       "}",
       "void ShowAbsyn::visitString(String s)",
       "{",
       "  bufAppend('\\\"');",
-      "  bufAppend(s);",
+      "  bufEscape(s);",
       "  bufAppend('\\\"');",
       "}",
       "void ShowAbsyn::visitIdent(String s)",

diff --git a/source/src/BNFC/Backend/Java/CFtoJavaPrinter15.hs b/source/src/BNFC/Backend/Java/CFtoJavaPrinter15.hs
@@ -84,7 +84,17 @@ cf2JavaPrinter packageBase packageAbsyn cf =
       "  private static void sh(Character c) { render(\"'\" + c.toString() + \"'\"); }",
       "  private static void sh(String s) { printQuoted(s); }",
       "",
-      "  private static void printQuoted(String s) { render(\"\\\"\" + s + \"\\\"\"); }",
+      "  private static void printQuoted(String s) { render(\"\\\"\" + escape(s) + \"\\\"\"); }",
+      "",
+      "  public static String escape(String s) {",
+      "    return s.replace(\"\\\\\", \"\\\\\\\\\")",
+      "            .replace(\"\\t\", \"\\\\t\")",
+      "            .replace(\"\\b\", \"\\\\b\")",
+      "            .replace(\"\\n\", \"\\\\n\")",
+      "            .replace(\"\\r\", \"\\\\r\")",
+      "            .replace(\"\\f\", \"\\\\f\")",
+      "            .replace(\"\\\"\", \"\\\\\\\"\");",
+      "  }",
       "",
       "  private static void indent()",
       "  {",

diff --git a/testing/regression-tests/358_MixFixLists/good01.in b/testing/regression-tests/358_MixFixLists/good01.in
@@ -11,6 +11,7 @@ foo
 "A".
 "B".
 "QED".
+"line1\nline2".
 semi-exprs:
 1+1;
 2+2;

diff --git a/testing/regression-tests/358_MixFixLists/good01.out b/testing/regression-tests/358_MixFixLists/good01.out
@@ -4,7 +4,7 @@ Parse Successful!
 
 [Abstract Syntax]
 
-Top [1,2,3] [Foo,Bar,Baz] ["A","B","QED"] [EPlus (EInt 1) (EInt 1),EPlus (EInt 2) (EInt 2)] [EInt 3,EPlus (EInt 4) (EInt 4)] "ABC"
+Top [1,2,3] [Foo,Bar,Baz] ["A","B","QED","line1\nline2"] [EPlus (EInt 1) (EInt 1),EPlus (EInt 2) (EInt 2)] [EInt 3,EPlus (EInt 4) (EInt 4)] "ABC"
 
 [Linearized tree]
 
@@ -21,6 +21,6 @@ foo
     finally baz
   }
 }
-"A" . "B" . "QED" . semi-exprs: 1 + 1;
+"A" . "B" . "QED" . "line1\nline2" . semi-exprs: 1 + 1;
 2 + 2;
 comma-exprs: 3, (4 + 4), chars: 'A' !, 'B' !, 'C' .
diff --git a/testing/regression-tests/358_MixFixLists/test.cf b/testing/regression-tests/358_MixFixLists/test.cf
@@ -2,6 +2,7 @@
 -- Issue #361, C++ list parsing.
 -- Issue #366, render } on new line.
 -- Issue #359, Haskell: print Char lists.
+-- Issue #449  C/C++/Java: print escape characters in String.
 
 Top.   S ::= "{" [Integer]
              [FooBar]