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=-0.8 required=5.0 tests=BAYES_00,INVALID_DATE autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,87fae37c03e8e6bf X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 1994-11-26 00:36:20 PST Path: nntp.gmd.de!xlink.net!howland.reston.ans.net!gatech!paladin.american.edu!auvm!GTEWD.MTV.GTEGSC.COM!papayd Comments: Gated by NETNEWS@AUVM.AMERICAN.EDU Newsgroups: comp.lang.ada Message-ID: <0098804D.E588BAC0.46@gtewd.mtv.gtegsc.com> Date: Sat, 26 Nov 1994 00:34:11 PST Sender: Ada programming language From: Dave Papay M/S 7G32 x2791 Subject: Re: The 'BASE Attribute Date: 1994-11-26T00:34:11-08:00 List-Id: Program Validation L writes: >We are confused by the meaning of the 'BASE attribute. For example, the >LRM states that a fixed point type declaration of the form: > >type T is delta D range L .. R; > >is, by definition, equivalent to the following declarations: > >type fixed_point_type is new predefined_fixed_point_type; >subtype T is fixed_point_type > range fixed_point_type(L) .. fixed_point_type(R); > >We would therefore expect T to denote the (implicitly declared) subtype, >and T'BASE to denote the anonymous type fixed_point_type. This would mean >that T'DELTA is valid, whilst T'BASE'DELTA is invalid, since P'DELTA is >only defined for fixed point subtypes. T'BASE'DELTA is legal, since in 3.3(4) the LRM states: "A type is a subtype of itself..." Also, although the description for the 'DELTA attribute in 3.5.10(4) states that it "Yields the value of the delta specified in the fixed accuracy definition for the *subtype* T" (emphasis added), 3.5.10(2) states that the attributes listed below (which includes 'DELTA) are define "for every fixed point *type or subtype* T" (again, emphasis added). This paragraph also explains why T is referred to as a subtype in some contexts, and as a type in others. Hope this helps. | | David Papay | o | papay@acm.org (preferred) | ^/--- | dpapay@aol.com (alternate) | /> | | | | fleche! |