diff --git a/lib/bcore/bcore_precoder.c b/lib/bcore/bcore_precoder.c
index f6270ad2..686554ec 100644
--- a/lib/bcore/bcore_precoder.c
+++ b/lib/bcore/bcore_precoder.c
@@ -880,15 +880,29 @@ static bl_t bcore_precoder_s_register_group( bcore_precoder_s* o, const bcore_pr
 
 static void bcore_precoder_group_s_compile( bcore_precoder_group_s* o, bcore_source* source )
 {
+    sc_t precode_termination = NULL;
+
     while( !bcore_source_a_eos( source ) )
     {
-        if( bcore_source_a_parse_bl_fa( source, "#?'/*'" ) ) break;
+        if( bcore_source_a_parse_bl_fa( source, "#?'/*'" ) )
+        {
+            bcore_source_a_parse_fa( source, "#skip'*'" );
+            precode_termination = " #?'*/'";
+            break;
+        }
+        else if( bcore_source_a_parse_bl_fa( source, "#?'#ifdef'" ) )
+        {
+            bcore_source_a_parse_fa( source, " BETH_PRECODE_SECTION " );
+            precode_termination = " #?'#endif'";
+            break;
+        }
+
         char c = bcore_source_a_get_u0( source );
-        if( c != ' ' && c != '\t' && c != '\n' ) bcore_source_a_parse_err_fa( source, "Opening c-style comment '/*' expected." );
+        if( c != ' ' && c != '\t' && c != '\n' ) bcore_source_a_parse_err_fa( source, "Opening c-style comment '/*' or '#<sc_t>' expected.", "#ifdef BETH_PRECODE_SECTION" );
     }
-    bcore_source_a_parse_fa( source, "#skip'*'" );
 
-    while( !bcore_source_a_parse_bl_fa( source, " #?'*/'" ) )
+
+    while( !bcore_source_a_parse_bl_fa( source, precode_termination ) )
     {
         if( bcore_source_a_eos( source ) )  bcore_source_a_parse_err_fa( source, "Closing c-style comment '*/' expected." );
 
@@ -1118,7 +1132,7 @@ static void bcore_precoder_source_s_compile( bcore_precoder_source_s* o, bcore_s
 {
     while( !bcore_source_a_eos( source ) )
     {
-        if( bcore_source_a_parse_bl_fa( source, "#?'BETH_PRECODE'" ) )
+        if( bcore_source_a_parse_bl_fa( source, "#?w'BETH_PRECODE'" ) )
         {
             bcore_precoder_group_s* group = bcore_precoder_group_s_create();
             group->source = o;
diff --git a/lib/bcore/bcore_precoder.h b/lib/bcore/bcore_precoder.h
index c0886b68..733f8653 100644
--- a/lib/bcore/bcore_precoder.h
+++ b/lib/bcore/bcore_precoder.h
@@ -30,13 +30,20 @@
  *
  *  Usage:
  *  BCORE_PRECODE( <group_name> )
- *  <opening c-comment>
+ *  <precode-opener>
  *      feature [strict] '<flags>' <ret> <func_name>( const | mutable, <args> ) [ = <default_func> ];
  *
  *      self <name> = <trait> { reflection-definition };
  *
  *      ...
- *  <closing c-comment>
+ *  <precode-closer>
+ *
+ *  precode-opener:
+ *    c-style comment-opener or '#ifdef BETH_PRECODE_SECTION'
+ *    Macro BETH_PRECODE_SECTION must never be defined.
+ *
+ *  precode-closer:
+ *    c-style comment-closer or '#endif' (depending on what was used for precode-opener)
  *
  *   feature:
  *       The feature definition triggers implicit definition of a perspective <group_name>
diff --git a/lib/bmath/bmath_adaptive.h b/lib/bmath/bmath_adaptive.h
index b34d1c49..c9749a25 100644
--- a/lib/bmath/bmath_adaptive.h
+++ b/lib/bmath/bmath_adaptive.h
@@ -73,7 +73,7 @@ f3_t bmath_adaptive_a_adapt_1( bmath_adaptive* o, const bmath_vf3_s* in, f3_t ta
 /// training challenge: distinguish a sine wave from random walk
 void bmath_adaptive_a_test_sine_random( const bmath_adaptive* o );
 
-/// training challenge: learn binay adding of numbers
+/// training challenge: learn binary adding of numbers
 void bmath_adaptive_a_test_encode_add( const bmath_adaptive* o );
 
 /**********************************************************************************************************************/