From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,FREEMAIL_FROM
	autolearn=unavailable autolearn_force=no version=3.4.4
X-Received: by 2002:a02:95ae:: with SMTP id b43mr25013775jai.4.1546107640027;
        Sat, 29 Dec 2018 10:20:40 -0800 (PST)
X-Received: by 2002:aca:4c97:: with SMTP id z145mr380852oia.2.1546107639754;
 Sat, 29 Dec 2018 10:20:39 -0800 (PST)
Path: 
 eternal-september.org!reader01.eternal-september.org!feeder.eternal-september.org!news.uzoreto.com!feeder.erje.net!2.eu.feeder.erje.net!newsreader4.netcologne.de!news.netcologne.de!peer03.ams1!peer.ams1.xlned.com!news.xlned.com!peer03.am4!peer.am4.highwinds-media.com!peer01.iad!feed-me.highwinds-media.com!news.highwinds-media.com!k10no206948itk.0!news-out.google.com!v71ni229ita.0!nntp.google.com!q69no207925itb.0!postnews.google.com!glegroupsg2000goo.googlegroups.com!not-for-mail
Newsgroups: comp.lang.ada
Date: Sat, 29 Dec 2018 10:20:39 -0800 (PST)
Complaints-To: groups-abuse@google.com
Injection-Info: glegroupsg2000goo.googlegroups.com;
 posting-host=2003:e7:ff1c:4fc:d63d:7eff:fe98:7b00;
 posting-account=Md_OIgoAAAAkZyQ6nYoc3WBIThMpPfV7
NNTP-Posting-Host: 2003:e7:ff1c:4fc:d63d:7eff:fe98:7b00
User-Agent: G2/1.0
MIME-Version: 1.0
Message-ID: <30ba8954-a19e-4c95-b350-798b0276db41@googlegroups.com>
Subject: Ada grammar rules for names too permissive?
From: olivermkellogg@gmail.com
Injection-Date: Sat, 29 Dec 2018 18:20:39 +0000
Content-Type: text/plain; charset="UTF-8"
X-Received-Bytes: 2208
X-Received-Body-CRC: 1637597563
Xref: reader01.eternal-september.org comp.lang.ada:55122
Date: 2018-12-29T10:20:39-08:00
List-Id: <comp.lang.ada>

Hi,

RM section 3.2.2 defines

  subtype_mark ::= (subtype_)name

where (subtype_) is subtype_ rendered in italics, i.e. essentially

  subtype_mark ::= name

This looks overly permissive to me, considering 4.1

  name ::=
     direct_name | explicit_dereference
   | indexed_component | slice
   | selected_component | attribute_reference
   | type_conversion | function_call
   | character_literal | qualified_expression
   | generalized_reference | generalized_indexing
   | target_name

The AARM elaborates in paragraph 4a:

*Ramification*: Note that name includes attribute_reference; thus, S'Base can be used as a subtype_mark.

My question is, why is subtype_mark not defined as follows:

  compound_name ::= identifier { . identifier }

  subtype_mark ::= compound_name [ ' Base ]


Similarly, RM section 10.1.1 defines

  parent_unit_name ::= name

Here my question also applies, why not

  parent_unit_name ::= compound_name


- Oliver
(currently fighting ambiguities in the ANTLR grammar caused by laxity of rules)