grammar: Kill another amount of redundant parsers

This way we will include a couple less look-up tables for the
digit parsing.

grammar/SIPGrammar.st

@@ -25,6 +25,7 @@ PP.PPCompositeParser subclass: SIPGrammar [
       Request RequestLine Method extension_method
       RequestURI quoted_string token commonUriParser paramchar
       header generic_param tag_param digest_cln auth_param host
+      digitParser digitParserMin
     |
     "http://sofia-sip.org/repos/sofia-sip/libsofia-sip-ua/sip/GRAMMAR"
     <category: 'OsmoSIP-Grammar'>
@@ -35,6 +36,14 @@ PP.PPCompositeParser subclass: SIPGrammar [
         ^ Request / Response
     ]
 
+    digitParser [
+        ^#digit asParser
+    ]
+
+    digitParserMin [
+        ^digitParser min: 1 max: 3
+    ]
+
     CRLF [
         <category: 'misc'>
         ^ Character cr asParser, Character nl asParser
@@ -48,7 +57,7 @@ PP.PPCompositeParser subclass: SIPGrammar [
     URI [
         "TODO: URI should be parsed properly but yate seems to already
         violate the RFC"
-        ^(#digit asParser / #word asParser) star
+        ^(digitParser / #word asParser) star
         "^absoluteURI / abs-path"
     ]
 
@@ -97,7 +106,7 @@ PP.PPCompositeParser subclass: SIPGrammar [
 
     port [
         <category: 'generic'>
-        ^ #digit asParser plus flatten
+        ^ digitParser plus flatten
     ]
 
     uri_parameters [
@@ -195,7 +204,7 @@ PP.PPCompositeParser subclass: SIPGrammar [
 
     unreserved [
         <category: 'generic'>
-        ^ (#letter asParser / #digit asParser) / self mark
+        ^ (#letter asParser / digitParser) / self mark
     ]
 
     reserved [
@@ -246,7 +255,7 @@ PP.PPCompositeParser subclass: SIPGrammar [
     StatusCode [
         <category: 'response'>
         "Combined into one..."
-        ^ (#digit asParser min: 3 max: 3) flatten
+        ^ (digitParser min: 3 max: 3) flatten
     ]
 
     ReasonPhrase [
@@ -314,24 +323,26 @@ PP.PPCompositeParser subclass: SIPGrammar [
 
     response_port [
         <category: 'via'>
-        ^'rport' asParser, (EQUAL, #digit asParser plus) optional
+        ^'rport' asParser, (EQUAL, digitParser plus) optional
     ]
 
     ttl [
         <category: 'generic'>
-        ^ #digit asParser min: 1 max: 3
+        ^ digitParserMin
     ]
 
     IPv4address [
-        ^ (#digit asParser min: 1 max: 3), $. asParser,
-          (#digit asParser min: 1 max: 3), $. asParser,
-          (#digit asParser min: 1 max: 3), $. asParser,
-          (#digit asParser min: 1 max: 3).
+        | dotParser |
+        dotParser := $. asParser.
+        ^ (digitParserMin), dotParser,
+          (digitParserMin), dotParser,
+          (digitParserMin), dotParser,
+          (digitParserMin).
     ]
 
     CSeq [
         <category: 'cseq'>
-        ^ 'CSeq' asParser, HCOLON, (#digit asParser plus flatten, LWS, Method)
+        ^ 'CSeq' asParser, HCOLON, (digitParser plus flatten, LWS, Method)
     ]
 
     generic_param [
@@ -650,7 +661,7 @@ PP.PPCompositeParser subclass: SIPGrammar [
 
     delta_seconds [
         <category: 'contact'>
-        ^ #digit asParser plus
+        ^ digitParser plus
     ]
 
     extension_header [
@@ -660,7 +671,7 @@ PP.PPCompositeParser subclass: SIPGrammar [
 
     qvalue [
         <category: 'generic'>
-        ^ ($0 asParser, ($. asParser, #digit asParser max: 3) optional) /
+        ^ ($0 asParser, ($. asParser, digitParser max: 3) optional) /
           ($1 asParser, ($. asParser, $0 asParser max: 3) optional)
     ]
 
@@ -681,7 +692,7 @@ PP.PPCompositeParser subclass: SIPGrammar [
     header_value [
         <category: 'generic'>
         "TODO: TEXT-UTF8char / UTF8-CONT"
-        ^ (#letter asParser / #digit asParser / #punctuation asParser / #blank asParser / LWS) star flatten
+        ^ (#letter asParser / digitParser / #punctuation asParser / #blank asParser / LWS) star flatten
     ]
 
     HTAB [