Issue #108 - first cut new option --indent-with-tabs yes.

include/tidyenum.h

@@ -80,7 +80,7 @@ typedef enum
 typedef enum
 {
   TidyUnknownOption,   /**< Unknown option! */
-  TidyIndentSpaces,    /**< Indentation n spaces */
+  TidyIndentSpaces,    /**< Indentation n spaces/tabs */
   TidyWrapLen,         /**< Wrap margin */
   TidyTabSize,         /**< Expand tabs to n spaces */
 
@@ -204,6 +204,7 @@ typedef enum
   TidySortAttributes,      /**< Sort attributes */
   TidyMergeSpans,       /**< Merge multiple SPANs */
   TidyAnchorAsName,    /**< Define anchors as name attributes */
+  TidyPPrintTabs,       /**< Indent using tabs istead of spaces */
   N_TIDY_OPTIONS       /**< Must be last */
 } TidyOptionId;
 

src/config.c

@@ -204,6 +204,13 @@ static ParseProperty ParseDocType;
 /* keep-first or keep-last? */
 static ParseProperty ParseRepeatAttr;
 
+/*\
+ * 20150515 - support using tabs instead of spaces - Issue #108
+ * (a) parser for 't'/'f', 'true'/'false', 'y'/'n', 'yes'/'no' or '1'/'0' 
+ * (b) sets the TidyIndentSpaces to 1 if 'yes'
+ * (c) sets the indent_char to '\t' or ' '
+\*/
+static ParseProperty ParseTabs;
 
 static const TidyOptionImpl option_defs[] =
 {
@@ -313,6 +320,7 @@ static const TidyOptionImpl option_defs[] =
   { TidySortAttributes,          PP, "sort-attributes",             IN, TidySortAttrNone,ParseSorter,       sorterPicks     },
   { TidyMergeSpans,              MU, "merge-spans",                 IN, TidyAutoState,   ParseAutoBool,     autoBoolPicks   },
   { TidyAnchorAsName,            MU, "anchor-as-name",              BL, yes,             ParseBool,         boolPicks       },
+  { TidyPPrintTabs,              PP, "indent-with-tabs",            BL, no,              ParseTabs,         NULL            }, /* 20150515 - Issue #108 */
   { N_TIDY_OPTIONS,              XX, NULL,                          XY, 0,               NULL,              NULL            }
 };
 
@@ -1204,6 +1212,30 @@ Bool ParseCSS1Selector( TidyDocImpl* doc, const TidyOptionImpl* option )
     return yes;
 }
 
+/*\
+ * 20150515 - support using tabs instead of spaces - Issue #108
+ * Sets the indent character to a tab if on, and set indent space count to 1
+ * and sets indent character to a space if off.
+\*/
+Bool ParseTabs( TidyDocImpl* doc, const TidyOptionImpl* entry )
+{
+    ulong flag = 0;
+    Bool status = ParseTriState( TidyNoState, doc, entry, &flag );
+    if ( status ) {
+        Bool tabs = flag != 0 ? yes : no;
+        TY_(SetOptionBool)( doc, entry->id, tabs );
+        if (tabs) {
+            TY_(PPrintTabs)();
+            TY_(SetOptionInt)( doc, TidyIndentSpaces, 1 );
+        } else {
+            TY_(PPrintSpaces)();
+            /* optional - TY_(ResetOptionToDefault)( doc, TidyIndentSpaces ); */
+        }
+    }
+    return status;
+}
+
+
 /* Coordinates Config update and Tags data */
 static void DeclareUserTag( TidyDocImpl* doc, TidyOptionId optId,
                             UserTagType tagType, ctmbstr name )

src/localize.c

@@ -745,7 +745,7 @@ static const TidyOptionDoc option_docs[] =
   {TidyTabSize,
    "This option specifies the number of columns that Tidy uses between "
    "successive tab stops. It is used to map tabs to spaces when reading the "
-   "input. Tidy never outputs tabs. "
+   "input. "
   },
   {TidyVertSpace,
    "This option specifies if Tidy should add some empty lines for "
@@ -914,6 +914,14 @@ static const TidyOptionDoc option_docs[] =
    "is added along an existing id attribute if the DTD allows it. "
    "If set to \"no\", any existing name attribute is removed "
    "if an id attribute exists or has been added. "
+  },
+   {TidyPPrintTabs,
+   "Set this option \"on\" to indent using tabs instead of the default "
+   "spaces. The option TidyIndentSpaces controls the number of tabs output "
+   "per level of indent, which is reset to 1, when this option is set on. "
+   "And of course, indent must be enabled for this to have any effect. "
+   "Note TidyTabSize controls converting input tabs to spaces. Set to zero "
+   "to retain input tabs. "
   },
   {N_TIDY_OPTIONS,
    NULL

src/pprint.c

@@ -36,6 +36,21 @@ static int  TextStartsWithWhitespace( Lexer *lexer, Node *node, uint start, uint
 static Bool InsideHead( TidyDocImpl* doc, Node *node );
 static Bool ShouldIndent( TidyDocImpl* doc, Node *node );
 
+/*\
+ * 20150515 - support using tabs instead of spaces - Issue #108
+ * GH: https://github.com/htacg/tidy-html5/issues/108 - Keep indent with tabs #108
+ * SF: https://sourceforge.net/p/tidy/feature-requests/3/ - #3 tabs in place of spaces
+\*/
+static uint indent_char = ' ';
+void TY_(PPrintTabs)(void)
+{
+    indent_char = '\t';
+}
+void TY_(PPrintSpaces)(void)
+{
+    indent_char = ' ';
+}
+
 #if SUPPORT_ASIAN_ENCODINGS
 /* #431953 - start RJ Wraplen adjusted for smooth international ride */
 
@@ -582,7 +597,7 @@ static void WrapLine( TidyDocImpl* doc )
     {
         uint spaces = GetSpaces( pprint );
         for ( i = 0; i < spaces; ++i )
-            TY_(WriteChar)( ' ', doc->docOut );
+            TY_(WriteChar)( indent_char, doc->docOut ); /* 20150515 - Issue #108 */
     }
 
     for ( i = 0; i < pprint->wraphere; ++i )
@@ -633,7 +648,7 @@ static void WrapAttrVal( TidyDocImpl* doc )
     {
         uint spaces = GetSpaces( pprint );
         for ( i = 0; i < spaces; ++i )
-            TY_(WriteChar)( ' ', doc->docOut );
+            TY_(WriteChar)( indent_char, doc->docOut ); /* 20150515 - Issue #108 */
     }
 
     for ( i = 0; i < pprint->wraphere; ++i )
@@ -660,7 +675,7 @@ static void PFlushLineImpl( TidyDocImpl* doc )
     {
         uint spaces = GetSpaces( pprint );
         for ( i = 0; i < spaces; ++i )
-            TY_(WriteChar)( ' ', doc->docOut );
+            TY_(WriteChar)( indent_char, doc->docOut ); /* 20150515 - Issue #108 */
     }
 
     for ( i = 0; i < pprint->linelen; ++i )

src/pprint.h

@@ -84,5 +84,10 @@ void TY_(PPrintTree)( TidyDocImpl* doc, uint mode, uint indent, Node *node );
 
 void TY_(PPrintXMLTree)( TidyDocImpl* doc, uint mode, uint indent, Node *node );
 
+/*\
+ * 20150515 - support using tabs instead of spaces
+\*/
+void TY_(PPrintTabs)(void);
+void TY_(PPrintSpaces)(void);
 
 #endif /* __PPRINT_H__ */