diff --git a/doc/bison.texinfo b/doc/bison.texinfo
index 8f40afbe..651645d9 100644
--- a/doc/bison.texinfo
+++ b/doc/bison.texinfo
@@ -9249,9 +9249,9 @@ exp:
 | exp "-" exp   @{ $$ = $1 - $3; @}
 | exp "*" exp   @{ $$ = $1 * $3; @}
 | exp "/" exp   @{ $$ = $1 / $3; @}
-| "(" exp ")"   @{ std::swap($$, $2); @}
+| "(" exp ")"   @{ std::swap ($$, $2); @}
 | "identifier"  @{ $$ = driver.variables[$1]; @}
-| "number"      @{ std::swap($$, $1); @};
+| "number"      @{ std::swap ($$, $1); @};
 %%
 @end example