From: "Bart Schaefer" <schaefer@candle.brasslantern.com>
To: zsh-workers@sunsite.auc.dk (Zsh hackers list)
Subject: Re: PATCH: 3.1.6-pws-4: floating point support
Date: Sat, 18 Sep 1999 18:21:42 +0000 [thread overview]
Message-ID: <990918182142.ZM6200@candle.brasslantern.com> (raw)
In-Reply-To: <9909171223.AA32858@ibmth.df.unipi.it>
On Sep 17, 2:23pm, Peter Stephenson wrote:
} Subject: PATCH: 3.1.6-pws-4: floating point support
}
} Here's my first go at floating point support.
}
} Outside an immediate numeric context, such as a $((...)) or a normal array
} subscript, there is no special way of telling whether an integer or float
} is required. So if you need an integer but use a float, the decimal point
} is liable to get in the way. But that's inevitable.
What's the most appropriate idiom for forcing a floating point number to be
interpreted as an integer, e.g. to force integer division?
The thing that bothers me most -- and I don't know what if anything ksh does
about this, so maybe it's moot -- is that
((x=y))
where y is float and x was not previously defined, creates x as float, which
may be unexpected (if the assignment is in code that's held over from pre-
float zsh). This is similar to, but more subtle than, the for-((...))-loop
problem that appears as an example in the doc. Being required to predeclare
variables with "integer" or "float" from outside the ((...)) context feels
a bit clumsy to me, so I hope there's a better way.
While doing some random fooling around with this, I noticed:
zagzig<23> ((integer florp=9.2))
zsh: bad math expression: unbalanced stack
zagzig<24> typeset -F
florp=9.2000000000
The variable got assigned in spite of the syntax error? Ouch.
Finally, there's a typo in the doc.
Index: Doc/Zsh/builtins.yo
===================================================================
@@ -348,7 +348,7 @@
If no var(job) is specified, resume the current job.
)
findex(float)
-item(tt(float) [ {tt(PLUE())|tt(-)}tt(EFghlrtux) ] [ var(name)[tt(=)var(value)] ... ])(
+item(tt(float) [ {tt(PLUS())|tt(-)}tt(EFghlrtux) ] [ var(name)[tt(=)var(value)] ... ])(
Equivalent to tt(typeset -E), except that options irrelevant to floating
point numbers are not permitted.
)
--
Bart Schaefer Brass Lantern Enterprises
http://www.well.com/user/barts http://www.brasslantern.com
next prev parent reply other threads:[~1999-09-18 18:21 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
1999-09-17 12:23 Peter Stephenson
1999-09-18 18:21 ` Bart Schaefer [this message]
1999-09-20 9:14 ` Peter Stephenson
1999-09-20 16:14 ` Peter Stephenson
1999-09-17 13:18 Sven Wischnowsky
1999-09-17 12:51 ` Peter Stephenson
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