Don't waste words describing the SET type

Since the SET type is used exactly the same way as the SEQUENCE
type in Erlang, we can simply say so and note that decoding will
be less efficient for the BER and DER encoding rules.

1 files changed, 4 insertions, 62 deletions

diff --git a/lib/asn1/doc/src/asn1_ug.xml b/lib/asn1/doc/src/asn1_ug.xml
index a16aac0e03..dd08eb1817 100644
--- a/lib/asn1/doc/src/asn1_ug.xml
+++ b/lib/asn1/doc/src/asn1_ug.xml
@@ -949,68 +949,10 @@ ok
     <section>
       <marker id="SET"></marker>
       <title>SET</title>
-      <p>The SET type is an unusual construct and normally the SEQUENCE 
-        type is more appropriate to use. Set is also inefficient compared with SEQUENCE, as the components can be in any order. Hence, it must be possible
-        to distinguish every component in 'SET', both when
-        encoding and decoding a value of a type defined to be a SET.
-        The tags of all components must be different from each other
-        in order to  be easily recognizable.</p>
-      <p>A SET may be defined as:</p>
-      <pre>
-Pdu2 ::= SET {
-    a INTEGER,
-    b BOOLEAN,
-    c ENUMERATED {on(0),off(1)} }      </pre>
-      <p>A SET is represented as an Erlang record.
-        For each SEQUENCE and <c>SET</c> in
-        an ASN.1 module an Erlang record declaration is generated. For
-        <c>Pdu2</c> above a record is defined like this:</p>
-      <pre>
--record('Pdu2',{a, b, c}).      </pre>
-      <p>The record declarations for a module <c>M</c> are placed in a 
-        separate <c>M.hrl</c> file.</p>
-      <p>Values can be assigned in Erlang as demonstrated below:</p>
-      <pre>
-V = #'Pdu2'{a=44,b=false,c=off}.      </pre>
-      <p>The decode functions will return a record as result when decoding 
-        a SET.
-        </p>
-      <p>The difference between SET and SEQUENCE is that the order of
-        the components (in the BER encoded format) is undefined for SET
-        and defined as the lexical order from the ASN.1 definition for
-        SEQUENCE. The ASN.1 compiler for Erlang will always encode a
-        SET in the lexical order. The decode routines can handle SET
-        components encoded in any order but will always return the
-        result as a record. Since all components of the SET must be
-        distinguishable both in the encoding phase as well as the
-        decoding phase the following type is not allowed in a module
-        with EXPLICIT or IMPLICIT as tag-default :</p>
-      <p></p>
-      <pre>
-Bad ::= SET {i INTEGER,
-             j INTEGER }      </pre>
-      <p>The  ASN.1 to Erlang compiler  rejects the above type. We
-        shall not explain the concept of tag further here, we refer to
-        [<cite id="X.680"></cite>].
-        </p>
-      <p>Encoding of a SET with components with DEFAULT values behaves
-        similar as a SEQUENCE. The DER encoding format restrictions on DEFAULT
-        values is the same for SET as for SEQUENCE, and is supported by 
-        the compiler.</p>
-      <p>Moreover, in DER the elements of a SET will be sorted. If a 
-        component is an un-tagged choice the sorting have to take place
-        in run-time. This fact emphasizes the following recommendation
-        if DER encoding format is used.</p>
-      <p>The concept of SET is an unusual
-        construct and one  cannot think of one single application
-        where the set type is essential. (Imagine if someone
-        "invented'' the shuffled array in 'C') People tend to think
-        that 'SET' sounds nicer and more mathematical than 'SEQUENCE'
-        and hence use it when  'SEQUENCE' would have been more
-        appropriate. It is also most inefficient, since every correct
-        implementation of SET must always be prepared to accept the
-        components in any order. So, if possible use SEQUENCE instead
-        of SET.</p>
+      <p>In Erlang, the SET type is used exactly as SEQUENCE. Note
+      that if the BER or DER encoding rules are used, decoding a
+      SET is slower than decoding a SEQUENCE because the components
+      must be sorted.</p>
     </section>
 
     <section>