12.3  Differences between static and dynamic code

• Only dynamic procedures can have clauses added or removed at run time.
• Matching clauses (section 5.5) are not supported by dynamic code. A runtime error (about calling an undefined procedure -?->/1) will be raised when executing dynamic code that has a matching clause head.
• Clauses for a dynamic procedure need not be consecutive.
• Source tracing is not supported for dynamic procedures.
• assert/1, retract/1 and clause/1 do not perform clause transformation on the clause. If clause transformation is required, this can be done explicitly with expand_clause/2 before.
• Internally, dynamic procedures are represented differently from static procedures. The execution of dynamic procedures will generally be slower than for static procedures.