diff --git a/Makefile.am b/Makefile.am
index c8343a3..cf73e11 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -1,4 +1,5 @@
 AM_YFLAGS =		-d
+AM_LFLAGS =		-P dp
 BUILT_SOURCES =		lib/dice_parse.h
 
 lib_LTLIBRARIES =	libdice.la
@@ -6,13 +7,14 @@ libdice_la_SOURCES =	lib/dice_lexer.l \
 			lib/dice_parse.y \
 			lib/dice.h \
 			lib/dice.c \
-			lib/diceexpr.c
+			lib/diceexpr.c \
+			lex.dp.c
 
 include_HEADERS =	lib/dice.h
 
 AM_CFLAGS =		-Ilib
 
-libdice_la_LIBADD =	${BSD_LIBS}
+libdice_la_LIBADD =	${BSD_LIBS} -lm
 
 pkgconfig_DATA =	libdice.pc
 
diff --git a/configure.ac b/configure.ac
index 2cfa48e..a61f06b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,5 +1,5 @@
 AC_PREREQ([2.69])
-AC_INIT([libdice], [0.1], [florian@n0la.org])
+AC_INIT([libdice], [0.2], [florian@n0la.org])
 AM_INIT_AUTOMAKE([subdir-objects])
 LT_INIT()
 AC_CONFIG_HEADERS([config.h])
@@ -18,9 +18,8 @@ AC_CHECK_FUNCS([arc4random_uniform],,
 
 AC_CONFIG_FILES([Makefile tests/Makefile])
 
-AC_SEARCH_LIBS([cos], [m], [], [
-  AC_MSG_ERROR([unable to find the cos() function])
-])
+AC_SEARCH_LIBS([sqrt], [m])
+AC_SEARCH_LIBS([cos], [m])
 
 PKG_INSTALLDIR
 AC_CONFIG_FILES([libdice.pc])
diff --git a/lib/dice.c b/lib/dice.c
index b2f66a9..ee99dc4 100644
--- a/lib/dice.c
+++ b/lib/dice.c
@@ -30,12 +30,12 @@
 #include <bsd/stdlib.h>
 #endif
 
-extern int yylex_init_extra(void *extra, void **state);
-extern int yylex_destroy(void *state);
-extern void yylex(void *state);
-extern void yy_switch_to_buffer(void *buffer, void *scanner);
-extern void *yy_scan_string(char const *s, void *scanner);
-extern void yy_delete_buffer(void *b, void *scanner);
+extern int dplex_init_extra(void *extra, void **state);
+extern int dplex_destroy(void *state);
+extern void dplex(void *state);
+extern void dp_switch_to_buffer(void *buffer, void *scanner);
+extern void *dp_scan_string(char const *s, void *scanner);
+extern void dp_delete_buffer(void *b, void *scanner);
 
 struct dice_
 {
@@ -115,14 +115,14 @@ bool dice_parse(dice_t d, char const *s)
         return false;
     }
 
-    yylex_init_extra(d, &scanner);
-    buffer = yy_scan_string(s, scanner);
-    yy_switch_to_buffer(buffer, scanner);
+    dplex_init_extra(d, &scanner);
+    buffer = dp_scan_string(s, scanner);
+    dp_switch_to_buffer(buffer, scanner);
 
-    ret = yyparse(scanner, d);
+    ret = dpparse(scanner, d);
 
-    yy_delete_buffer(buffer, scanner);
-    yylex_destroy(scanner);
+    dp_delete_buffer(buffer, scanner);
+    dplex_destroy(scanner);
 
     if (ret) {
         return false;
diff --git a/lib/dice_lexer.c b/lib/dice_lexer.c
new file mode 100644
index 0000000..0a53ca5
--- /dev/null
+++ b/lib/dice_lexer.c
@@ -0,0 +1,2 @@
+/* empty file, so that autotools has something to compile
+ */
diff --git a/lib/dice_lexer.l b/lib/dice_lexer.l
index a90a239..981030c 100644
--- a/lib/dice_lexer.l
+++ b/lib/dice_lexer.l
@@ -1,7 +1,9 @@
+%option prefix="dp"
 %option bison-bridge
 %option reentrant
 
 %{
+#define YYSTYPE DPSTYPE
 #include "dice.h"
 #include "dice_parse.h"
 
diff --git a/lib/dice_parse.y b/lib/dice_parse.y
index 1c09530..9d1a1ae 100644
--- a/lib/dice_parse.y
+++ b/lib/dice_parse.y
@@ -1,4 +1,5 @@
 %define api.pure full
+%define api.prefix {dp}
 
 %parse-param {void *scanner} {dice_t dice}
 %lex-param {void *scanner}
@@ -6,14 +7,14 @@
 %{
 #include "dice.h"
 
-extern int yylex(void *lval, void *scanner);
+extern int dplex(void *lval, void *scanner);
 
-void yyerror(void *scanner, dice_t dice, char const *err)
+void dperror(void *scanner, dice_t dice, char const *err)
 {
     dice_set(dice, DICEOPTION_ERROR, err);
 }
 
-int yywrap(void)
+int dpwrap(void)
 {
     return 1;
 }