diff -a -B -d -E -r -u flex-2.5.4/flex.skl flex-2.5.4-pure-parser/flex.skl
--- flex-2.5.4/flex.skl	1996-09-10 17:58:54.000000000 -0600
+++ flex-2.5.4-pure-parser/flex.skl	2002-07-28 11:32:14.000000000 -0600
@@ -426,7 +426,7 @@
  */
 #ifndef YY_DECL
 %- Standard (non-C++) definition
-#define YY_DECL int yylex YY_PROTO(( void ))
+#define YY_DECL int yylex YY_PROTO( YYLEX_INTERFACE )
 %+ C++ definition
 #define YY_DECL int yyFlexLexer::yylex()
 %*
@@ -454,6 +454,12 @@
 
 %% user's declarations go here
 
+#ifdef YY_PURE_PARSER
+/* provide a common interface (so the user is able to use 'yylval' instead of '*yylval', e.g.) */
+#define yylval (*yylvalp)
+#define yylloc (*yyllocp)
+#endif
+
 	if ( yy_init )
 		{
 		yy_init = 0;
Only in flex-2.5.4-pure-parser: gen.o
Only in flex-2.5.4-pure-parser: libfl.a
Only in flex-2.5.4-pure-parser: libmain.o
Only in flex-2.5.4-pure-parser: libyywrap.o
diff -a -B -d -E -r -u flex-2.5.4/main.c flex-2.5.4-pure-parser/main.c
--- flex-2.5.4/main.c	1997-07-26 20:32:19.000000000 -0600
+++ flex-2.5.4-pure-parser/main.c	2002-07-28 11:44:03.000000000 -0600
@@ -57,6 +57,7 @@
 int interactive, caseins, lex_compat, do_yylineno, useecs, fulltbl, usemecs;
 int fullspd, gen_line_dirs, performance_report, backing_up_report;
 int C_plus_plus, long_align, use_read, yytext_is_array, do_yywrap, csize;
+int pure_parser, pure_yyltype, pure_param;
 int yymore_used, reject, real_reject, continued_action, in_rule;
 int yymore_really_used, reject_really_used;
 int datapos, dataline, linenum, out_linenum;
@@ -411,6 +412,13 @@
 
 		if ( C_plus_plus )
 			putc( '+', stderr );
+		if ( pure_parser ) {
+			putc( 'u', stderr );
+			if ( pure_yyltype )
+				putc( 'l', stderr );
+			if ( pure_param )
+				putc( 'r', stderr );
+		}
 		if ( backing_up_report )
 			putc( 'b', stderr );
 		if ( ddebug )
@@ -589,6 +597,7 @@
 
 	printstats = syntaxerror = trace = spprdflt = caseins = false;
 	lex_compat = C_plus_plus = backing_up_report = ddebug = fulltbl = false;
+	pure_parser = pure_yyltype = pure_param = false;
 	fullspd = long_align = nowarn = yymore_used = continued_action = false;
 	do_yylineno = yytext_is_array = in_rule = reject = do_stdinit = false;
 	yymore_really_used = reject_really_used = unspecified;
@@ -787,6 +796,14 @@
 				case 'T':
 					trace = true;
 					break;
+				
+				case 'u':
+					pure_parser = true;
+					if (strchr(arg + i + 1, 'l'))
+						pure_yyltype = true;
+					if (strchr(arg + i + 1, 'p'))
+						pure_param = true;
+					goto get_next_arg;
 
 				case 'v':
 					printstats = true;
@@ -1022,8 +1039,26 @@
 			}
 		}
 
+	else if ( pure_parser )
+		{
+		outn( "\n#define YY_PURE_PARSER 1" );
+		fputs( "#define YYLEX_INTERFACE ( YYSTYPE *yylvalp", stdout );
+
+		if ( pure_yyltype )
+			fputs( ", YYLTYPE *yyllocp", stdout );
+
+		if ( pure_param )
+			fputs( ", void *parm", stdout );
+
+		outn( " )" );
+		}
+	
 	else
+		outn( "\n#define YYLEX_INTERFACE ( void )" );
+	
+	if ( ! C_plus_plus )
 		{
+		
 		if ( yytext_is_array )
 			outn( "extern char yytext[];\n" );
 
@@ -1114,7 +1149,7 @@
 	FILE *f = stdout;
 
 	fprintf( f,
-_( "%s [-bcdfhilnpstvwBFILTV78+? -C[aefFmr] -ooutput -Pprefix -Sskeleton]\n" ),
+_( "%s [-bcdfhilnpstvwBFILTV78+? -u[lp] -C[aefFmr] -ooutput -Pprefix -Sskeleton]\n" ),
 		program_name );
 	fprintf( f, _( "\t[--help --version] [file ...]\n" ) );
 
@@ -1156,6 +1191,12 @@
 	fprintf( f, _( "\t-7  generate 7-bit scanner\n" ) );
 	fprintf( f, _( "\t-8  generate 8-bit scanner\n" ) );
 	fprintf( f, _( "\t-+  generate C++ scanner class\n" ) );
+	fprintf( f, _( "\t-u  generate a type of pure interface:\n" ) );
+	fprintf( f, _( "\t\t-ul  include YYLTYPE paramater\n" ) );
+	fprintf( f, _( "\t\t-up  include YYLEX_PARAM parameter\n" ) );
+	fprintf( f, _( "\t\t-ulp include both\n" ) );
+	fprintf( f, _( "\t\t-u   include neither; just yylex(yylval)" ) );
+	fprintf( f, _( "\t\tsee bison's info page for more information" ) );
 	fprintf( f, _( "\t-?  produce this help message\n" ) );
 	fprintf( f,
 _( "\t-C  specify degree of table compression (default is -Cem):\n" ) );
Only in flex-2.5.4-pure-parser: main.o
Only in flex-2.5.4-pure-parser: misc.o
Only in flex-2.5.4-pure-parser: nfa.o
Only in flex-2.5.4-pure-parser: parse.c
Only in flex-2.5.4-pure-parser: parse.h
Only in flex-2.5.4-pure-parser: parse.o
Only in flex-2.5.4-pure-parser: scan.c
Only in flex-2.5.4-pure-parser: scan.o
diff -a -B -d -E -r -u flex-2.5.4/skel.c flex-2.5.4-pure-parser/skel.c
--- flex-2.5.4/skel.c	1996-09-10 18:00:38.000000000 -0600
+++ flex-2.5.4-pure-parser/skel.c	2002-07-28 11:32:19.000000000 -0600
@@ -431,7 +431,7 @@
   " */",
   "#ifndef YY_DECL",
   "%- Standard (non-C++) definition",
-  "#define YY_DECL int yylex YY_PROTO(( void ))",
+  "#define YY_DECL int yylex YY_PROTO( YYLEX_INTERFACE )",
   "%+ C++ definition",
   "#define YY_DECL int yyFlexLexer::yylex()",
   "%*",
@@ -459,6 +459,12 @@
   "",
   "%% user's declarations go here",
   "",
+  "#ifdef YY_PURE_PARSER",
+  "/* provide a common interface (so the user is able to use 'yylval' instead of '*yylval', e.g.) */",
+  "#define yylval (*yylvalp)",
+  "#define yylloc (*yyllocp)",
+  "#endif",
+  "",
   "	if ( yy_init )",
   "		{",
   "		yy_init = 0;",