Restore list-based ABNF for Expect (#203)

draft-ietf-httpbis-semantics-latest.xml

@@ -5579,7 +5579,8 @@ Proxy-Authorization: basic aGVsbG86d29ybGQ=
    by this specification is <x:ref>100-continue</x:ref>.
 </t>
 <sourcecode type="abnf7230"><iref primary="true" item="Grammar" subitem="Expect"/>
-  <x:ref>Expect</x:ref>  = "100-continue"
+  <x:ref>Expect</x:ref> =      1#<x:ref>expectation</x:ref>
+  <x:ref>expectation</x:ref> = <x:ref>token</x:ref> [ "=" ( <x:ref>token</x:ref> / <x:ref>quoted-string</x:ref> ) *<x:ref>parameter</x:ref> ]
 </sourcecode>
 <t>
    The Expect field value is case-insensitive.
@@ -12218,7 +12219,7 @@ Content-Encoding: gzip
 <x:ref>Date</x:ref> = HTTP-date
 
 <x:ref>ETag</x:ref> = entity-tag
-<x:ref>Expect</x:ref> = "100-continue"
+<x:ref>Expect</x:ref> = expectation *( OWS "," OWS expectation )
 
 <x:ref>From</x:ref> = mailbox
 
@@ -12312,6 +12313,7 @@ Content-Encoding: gzip
 <x:ref>entity-tag</x:ref> = [ weak ] opaque-tag
 <x:ref>etagc</x:ref> = "!" / %x23-7E ; '#'-'~'
  / obs-text
+<x:ref>expectation</x:ref> = token [ "=" ( token / quoted-string ) *parameter ]
 
 <x:ref>field-content</x:ref> = field-vchar [ 1*( SP / HTAB / field-vchar )
  field-vchar ]

httpbis.abnf

@@ -22,7 +22,7 @@ Content-Range = range-unit SP ( range-resp / unsatisfied-range )
 Content-Type = media-type
 Date = HTTP-date
 ETag = entity-tag
-Expect = "100-continue"
+Expect = expectation *( OWS "," OWS expectation )
 Expires = HTTP-date
 From = mailbox
 GMT = %x47.4D.54 ; GMT
@@ -117,6 +117,7 @@ delta-seconds = 1*DIGIT
 entity-tag = [ weak ] opaque-tag
 etagc = "!" / %x23-7E ; '#'-'~'
  / obs-text
+expectation = token [ "=" ( token / quoted-string ) *parameter ]
 field-content = field-vchar [ 1*( SP / HTAB / field-vchar ) field-vchar ]
 field-line = field-name ":" OWS field-value OWS
 field-name = token