From: KFL@MIT-MC.ARPA (Keith F. Lynch)
Subject: Re: text_io considered error prone?
Date: Wed, 11-Sep-85 21:17:18 EDT [thread overview]
Date: Wed Sep 11 21:17:18 1985
Message-ID: <[MIT-MC.ARPA].642077.850911.KFL> (raw)
Date: Tue 10 Sep 85 22:34:22-EDT
From: "Art Evans" <Evans@TL-20B.ARPA>
As I read Chapter 14, Bakin's challange is unfair. In 14.3(6) and (7),
there is a careful definition of what Ada means by "text file". TEXT_IO
provides for I/O from such a file, and for nothing else. The last
sentence of (7) says
The effect of input or output of control characters (other than
horizontal tabulation) is not defined by the language.
Thus it's not surprising that copying an arbitrary string of ASCII
characters is beyond the capabilities of TEXT_IO.
I think that what 14.3.7 means is that the effect on the output device
is not defined. For instance some control character may make the output
device go into graphics mode, and that would not be a violation of the Ada
specs. The context can be judged by 2.1, which defines the Ada character
set as consisting of the letters, numerals, several special symbols, space
bar, and the control characters HT, VT, CR, LF, and FF. These characters
all have meaning to Ada. All other Ascii characters are merely arbitrary
bit patterns as far as Ada is concerned. It does NOT follow from that that
Ada is unable to copy a file containing such characters.
...Keith
next reply other threads:[~1985-09-12 1:17 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
1985-09-12 1:17 Keith F. Lynch [this message]
-- strict thread matches above, loose matches on Subject: below --
1985-09-17 12:44 Text_io considered error prone? "David S. Bakin"
1985-09-12 6:10 text_io " Paul Hilfinger
1985-09-11 3:32 "David S. Bakin"
[not found] <Bakin@MIT-MULTICS.ARPA>
1985-09-11 2:34 ` "Art Evans"
1985-09-11 0:46 "David S. Bakin"
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