diff --git a/data/xslt/xml2dot.xsl b/data/xslt/xml2dot.xsl
index dceb8e1e..7bd366d0 100644
--- a/data/xslt/xml2dot.xsl
+++ b/data/xslt/xml2dot.xsl
@@ -279,20 +279,20 @@
     <xsl:with-param name="dst" select="@state"/>
     <xsl:with-param name="style">
       <xsl:choose>
-	<xsl:when test="@symbol = 'error'">
-	  <xsl:text>dotted</xsl:text>
-	</xsl:when>
-	<xsl:when test="@type = 'shift'">
-	  <xsl:text>solid</xsl:text>
-	</xsl:when>
-	<xsl:otherwise>
-	  <xsl:text>dashed</xsl:text>
-	</xsl:otherwise>
+        <xsl:when test="@symbol = 'error'">
+          <xsl:text>dotted</xsl:text>
+        </xsl:when>
+        <xsl:when test="@type = 'shift'">
+          <xsl:text>solid</xsl:text>
+        </xsl:when>
+        <xsl:otherwise>
+          <xsl:text>dashed</xsl:text>
+        </xsl:otherwise>
       </xsl:choose>
     </xsl:with-param>
     <xsl:with-param name="label">
       <xsl:if test="not(@symbol = 'error')">
-	<xsl:value-of select="@symbol"/>
+        <xsl:value-of select="@symbol"/>
       </xsl:if>
     </xsl:with-param>
   </xsl:call-template>
diff --git a/data/xslt/xml2text.xsl b/data/xslt/xml2text.xsl
index 8b3f5ae4..53145965 100644
--- a/data/xslt/xml2text.xsl
+++ b/data/xslt/xml2text.xsl
@@ -253,9 +253,9 @@
     <xsl:text>&#10;</xsl:text>
     <xsl:apply-templates select="transition[@type = $type]">
       <xsl:with-param name="pad">
-	<xsl:call-template name="max-width-symbol">
-	  <xsl:with-param name="node" select="transition[@type = $type]"/>
-	</xsl:call-template>
+        <xsl:call-template name="max-width-symbol">
+          <xsl:with-param name="node" select="transition[@type = $type]"/>
+        </xsl:call-template>
       </xsl:with-param>
     </xsl:apply-templates>
   </xsl:if>
@@ -266,9 +266,9 @@
     <xsl:text>&#10;</xsl:text>
     <xsl:apply-templates select="error">
       <xsl:with-param name="pad">
-	<xsl:call-template name="max-width-symbol">
-	  <xsl:with-param name="node" select="error"/>
-	</xsl:call-template>
+        <xsl:call-template name="max-width-symbol">
+          <xsl:with-param name="node" select="error"/>
+        </xsl:call-template>
       </xsl:with-param>
     </xsl:apply-templates>
   </xsl:if>
@@ -279,9 +279,9 @@
     <xsl:text>&#10;</xsl:text>
     <xsl:apply-templates select="reduction">
       <xsl:with-param name="pad">
-	<xsl:call-template name="max-width-symbol">
-	  <xsl:with-param name="node" select="reduction"/>
-	</xsl:call-template>
+        <xsl:call-template name="max-width-symbol">
+          <xsl:with-param name="node" select="reduction"/>
+        </xsl:call-template>
       </xsl:with-param>
     </xsl:apply-templates>
   </xsl:if>
@@ -290,7 +290,7 @@
 <xsl:template match="item">
   <xsl:param name="pad"/>
   <xsl:param name="prev-rule-number"
-	     select="preceding-sibling::item[1]/@rule-number"/>
+             select="preceding-sibling::item[1]/@rule-number"/>
   <xsl:apply-templates
     select="key('bison:ruleByNumber', current()/@rule-number)"
   >
@@ -329,14 +329,14 @@
   <xsl:choose>
     <xsl:when test="$itemset != 'true' and $prev-lhs = lhs[text()]">
       <xsl:call-template name="lpad">
-	<xsl:with-param name="str" select="'|'"/>
-	<xsl:with-param name="pad" select="number(string-length(lhs[text()])) + 1"/>
+        <xsl:with-param name="str" select="'|'"/>
+        <xsl:with-param name="pad" select="number(string-length(lhs[text()])) + 1"/>
       </xsl:call-template>
     </xsl:when>
     <xsl:when test="$itemset = 'true' and $prev-lhs = lhs[text()]">
       <xsl:call-template name="lpad">
-	<xsl:with-param name="str" select="'|'"/>
-	<xsl:with-param name="pad" select="number(string-length(lhs[text()])) + 1"/>
+        <xsl:with-param name="str" select="'|'"/>
+        <xsl:with-param name="pad" select="number(string-length(lhs[text()])) + 1"/>
       </xsl:call-template>
     </xsl:when>
     <xsl:otherwise>
@@ -442,7 +442,7 @@
       <xsl:value-of select="@rule"/>
       <xsl:text> (</xsl:text>
       <xsl:value-of
-	  select="key('bison:ruleByNumber', current()/@rule)/lhs[text()]"/>
+          select="key('bison:ruleByNumber', current()/@rule)/lhs[text()]"/>
       <xsl:text>)</xsl:text>
     </xsl:otherwise>
   </xsl:choose>
@@ -479,9 +479,9 @@
   <xsl:variable name="longest">
     <xsl:for-each select="$node">
       <xsl:sort data-type="number" select="string-length(@symbol)"
-		order="descending"/>
+                order="descending"/>
       <xsl:if test="position() = 1">
-	<xsl:value-of select="string-length(@symbol)"/>
+        <xsl:value-of select="string-length(@symbol)"/>
       </xsl:if>
     </xsl:for-each>
   </xsl:variable>
@@ -498,7 +498,7 @@
     </xsl:when>
     <xsl:otherwise>
       <xsl:call-template name="space">
-	<xsl:with-param name="repeat" select="$diff"/>
+        <xsl:with-param name="repeat" select="$diff"/>
       </xsl:call-template>
       <xsl:value-of select="$str"/>
     </xsl:otherwise>
@@ -516,7 +516,7 @@
     <xsl:otherwise>
       <xsl:value-of select="$str"/>
       <xsl:call-template name="space">
-	<xsl:with-param name="repeat" select="$diff"/>
+        <xsl:with-param name="repeat" select="$diff"/>
       </xsl:call-template>
     </xsl:otherwise>
   </xsl:choose>
diff --git a/m4/flex.m4 b/m4/flex.m4
index 984c5143..5ab431a2 100644
--- a/m4/flex.m4
+++ b/m4/flex.m4
@@ -78,7 +78,7 @@ if test -z "${LEXLIB+set}"; then
     for ac_lib in '' -lfl -ll; do
       LIBS="$ac_lib $ac_save_LIBS"
       AC_LINK_IFELSE([AC_LANG_DEFINES_PROVIDED[`cat $LEX_OUTPUT_ROOT.c`]],
-	[ac_cv_lib_lex=$ac_lib])
+        [ac_cv_lib_lex=$ac_lib])
       test "$ac_cv_lib_lex" != 'none needed' && break
     done
     LIBS=$ac_save_LIBS
@@ -104,8 +104,8 @@ LIBS=$ac_save_LIBS
 dnl
 if test $ac_cv_prog_lex_yytext_pointer = yes; then
   AC_DEFINE([YYTEXT_POINTER], [1],
-	    [Define to 1 if `lex' declares `yytext' as a `char *' by default,
-	     not a `char[]'.])
+            [Define to 1 if `lex' declares `yytext' as a `char *' by default,
+             not a `char[]'.])
 fi
 rm -f conftest.l $LEX_OUTPUT_ROOT.c
 ])# _AC_PROG_LEX_YYTEXT_DECL
diff --git a/tests/glr-regression.at b/tests/glr-regression.at
index 41fc7bc7..6eb92886 100644
--- a/tests/glr-regression.at
+++ b/tests/glr-regression.at
@@ -651,7 +651,7 @@ AT_CLEANUP
 
 ## ------------------------------------------------------------------------- ##
 ## Incorrect default location for empty right-hand sides.  Adapted from bug  ##
-## report by Claudia Hermann.						     ##
+## report by Claudia Hermann.                                                ##
 ## See http://lists.gnu.org/archive/html/bug-bison/2005-10/msg00069.html and ##
 ## http://lists.gnu.org/archive/html/bug-bison/2005-10/msg00072.html         ##
 ## ------------------------------------------------------------------------- ##
@@ -677,25 +677,25 @@ AT_DATA_GRAMMAR([glr-regr8.y],
 %%
 
 
-PortClause	: T_PORT InterfaceDeclaration T_PORT
-		{ printf("%d/%d - %d/%d - %d/%d\n",
-			 @1.first_column, @1.last_column,
-			 @2.first_column, @2.last_column,
-			 @3.first_column, @3.last_column); }
-	;
+PortClause      : T_PORT InterfaceDeclaration T_PORT
+                { printf("%d/%d - %d/%d - %d/%d\n",
+                         @1.first_column, @1.last_column,
+                         @2.first_column, @2.last_column,
+                         @3.first_column, @3.last_column); }
+        ;
 
-InterfaceDeclaration	: OptConstantWord	%dprec 1
-	| OptSignalWord	%dprec 2
-	;
+InterfaceDeclaration    : OptConstantWord       %dprec 1
+        | OptSignalWord %dprec 2
+        ;
 
-OptConstantWord	: /* empty */
-	| T_CONSTANT
-	;
+OptConstantWord : /* empty */
+        | T_CONSTANT
+        ;
 
-OptSignalWord	: /* empty */
-		{ printf("empty: %d/%d\n", @$.first_column, @$.last_column); }
-	| T_SIGNAL
-	;
+OptSignalWord   : /* empty */
+                { printf("empty: %d/%d\n", @$.first_column, @$.last_column); }
+        | T_SIGNAL
+        ;
 
 %%
 
@@ -1058,7 +1058,7 @@ AT_CLEANUP
 
 
 ## ------------------------------------------------------------------------- ##
-## Incorrect lookahead during deterministic GLR.  See			     ##
+## Incorrect lookahead during deterministic GLR.  See                        ##
 ## <http://lists.gnu.org/archive/html/help-bison/2005-07/msg00017.html> and  ##
 ## <http://lists.gnu.org/archive/html/bison-patches/2006-01/msg00060.html>.  ##
 ## ------------------------------------------------------------------------- ##
@@ -1146,10 +1146,10 @@ print_lookahead (char const *reduction)
     {
       printf ("'%c', yylval='", yychar);
       if (yylval.value > ' ')
-	printf ("%c", yylval.value);
+        printf ("%c", yylval.value);
       printf ("', yylloc=(%d,%d),(%d,%d)",
-	      yylloc.first_line, yylloc.first_column,
-	      yylloc.last_line, yylloc.last_column);
+              yylloc.first_line, yylloc.first_column,
+              yylloc.last_line, yylloc.last_column);
     }
   printf ("\n");
 }
@@ -1246,7 +1246,7 @@ merge:
   | conflict defstate_look 'a' nonconflict2 'b' defstate_shift %dprec 2 {
     USE ($3); USE ($5);
     print_lookahead ("merge <- conflict defstate_look 'a' nonconflict2 'b'"
-		      " defstate_shift");
+                      " defstate_shift");
   }
   ;
 
@@ -1293,7 +1293,7 @@ alt1:
     USE ($1);
     if (yychar != 'd' && yychar != YYEOF)
       {
-	fprintf (stderr, "Incorrect lookahead during stack explosion.\n");
+        fprintf (stderr, "Incorrect lookahead during stack explosion.\n");
       }
   }
   ;
@@ -1302,7 +1302,7 @@ alt2:
     USE ($1);
     if (yychar != 'd' && yychar != YYEOF)
       {
-	fprintf (stderr, "Incorrect lookahead during stack explosion.\n");
+        fprintf (stderr, "Incorrect lookahead during stack explosion.\n");
       }
   }
   ;
@@ -1311,7 +1311,7 @@ alt3:
     USE ($1);
     if (yychar != 'd' && yychar != YYEOF)
       {
-	fprintf (stderr, "Incorrect lookahead during stack explosion.\n");
+        fprintf (stderr, "Incorrect lookahead during stack explosion.\n");
       }
   }
   ;
@@ -1319,8 +1319,8 @@ no_look:
   {
     if (yychar != YYEMPTY)
       {
-	fprintf (stderr,
-		 "Found lookahead where shouldn't during stack explosion.\n");
+        fprintf (stderr,
+                 "Found lookahead where shouldn't during stack explosion.\n");
       }
   }
   ;
@@ -1352,10 +1352,10 @@ print_lookahead (char const *reduction)
     {
       printf ("'%c', yylval='", yychar);
       if (yylval.value > ' ')
-	printf ("%c", yylval.value);
+        printf ("%c", yylval.value);
       printf ("', yylloc=(%d,%d),(%d,%d)",
-	      yylloc.first_line, yylloc.first_column,
-	      yylloc.last_line, yylloc.last_column);
+              yylloc.first_line, yylloc.first_column,
+              yylloc.last_line, yylloc.last_column);
     }
   printf ("\n");
 }
diff --git a/tests/torture.at b/tests/torture.at
index ac9e91ea..9b552b6f 100644
--- a/tests/torture.at
+++ b/tests/torture.at
@@ -91,9 +91,9 @@ for my $size (1 .. $max)
   {
     use Text::Wrap;
     print wrap ("| ", "   ",
-		(map { "\"$_\"" } (1 .. $size)),
-		" END \n"),
-		  "    { \$\$ = $size; }\n";
+                (map { "\"$_\"" } (1 .. $size)),
+                " END \n"),
+                  "    { \$\$ = $size; }\n";
   };
 print ";\n";
 
@@ -188,7 +188,7 @@ EOF
 use Text::Wrap;
 print
   wrap ("exp: ", "  ",
-	(map { "\"$_\"" } (1 .. $max)), ";"),
+        (map { "\"$_\"" } (1 .. $max)), ";"),
   "\n";
 
 print <<\EOF;
@@ -288,8 +288,8 @@ EOF
 
 print
   wrap ("%type <val> ",
-	"            ",
-	map { "n$_" } (1 .. $max)),
+        "            ",
+        map { "n$_" } (1 .. $max)),
   "\n";
 
 print "%token\n";