Hi Jacon!

The omit-construction is used for sending and receiving values. When sending,
the omitted value will of course not be there since you have explicitly told it
not to. When receiving you don't expect anything in that value's position and
hence matching will be "discarded" there.

In your example the variable will first be set to "10" (the optional field1) and
then reset to the value "omit". How this is implemented is (I think) up to each
tool vendor/implementation.

Continuing on your example I would say that the interest is when building the
send event. If you send something containing your variable before the second
assignment it will have the value "10", if you build your send event after the
second assignment it will contain the value "omit".

This is my opinion, there might be more...;-)

BR

/Stefan

---

Original Message

---

From: jacon wang
To: This email address is being protected from spambots. You need JavaScript enabled to view it.
Sent: 5/30/2003 2:57 AM
Subject: what does it imply by saying that optional fields shall be omitted
using the omit symbol.

Hello,TTCN3
In the clause 6.3.1.0(ETSI ES 201 873-1 V2.2.1(2003-2)),there is
a sentence that Optional fields shall be omitted using the omit symbol.
If the optional field has been assigned with non-omit value,
will the value of the field be changed by assigning the omit to it.

For example:
type record MyRecord
{
integer field1 optional,
boolean field2
}

var MyRecord r1;
r1 := {10,true};

//after the assignment,is the value of r1.field1 equal to 10?
r1 := {omit,true};

Best Regards,
2003-05-30
--
Engineering is the art of making what you want from things you can get.