[Maxima-bugs] [ maxima-Bugs-726420 ] floats with missing exponents / really minor

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Bugs item #726420, was opened at 2003-04-23 14:16
Message generated for change (Comment added) made by rtoy
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Category: None
Group: None
Status: Open
Resolution: None
Priority: 3
Submitted By: Barton Willis (willisb)
Assigned to: Nobody/Anonymous (nobody)
Summary: floats with missing exponents / really minor

Initial Comment:
Some software allows the exponent of a float to default
to zero.  In Maxima, this isn't the case

(C1) 4.2d;
(D1) 				     4.2D+
(C2) 4.2e;
(D2) 				     4.2E+
(C3) ?print(%);

4.2E+ 
(D3) 				     4.2E+
(C4) 4.2b;
Error: Unexpected end of #<string-input stream from "">.
Fast links are on: do (si::use-fast-links nil) for debugging
Error signalled by MACSYMA-TOP-LEVEL.
Broken at MREAD-RAW.  Type :H for Help.
MAXIMA>>

Maxima version: 5.9.0
Maxima build date: 19:10 2/9/2003
host type: i686-pc-mingw32
lisp-implementation-type: Kyoto Common Lisp
lisp-implementation-version: GCL-2-5.0

Not really a bug, but ...

Barton



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>Comment By: Raymond Toy (rtoy)
Date: 2003-05-15 20:33

Message:
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I think the following replacement in nparse.lisp will catch
these errors.   Help pick out a better error message.

(DEFUN SCAN-DIGITS (DATA CONTINUATION? CONTINUATION)
  (DO ((C (PARSE-TYIPEEK) (PARSE-TYIPEEK))
       (L () (CONS C L)))
      ((NOT (ASCII-NUMBERP C))
       (COND ((IMEMBER C CONTINUATION?)
	      (FUNCALL CONTINUATION (LIST* (NCONS (FIXNUM-CHAR-UPCASE
						   (PARSE-TYI)))
					   (NREVERSE L)
					   Data)
				   ))
	     ((null l)
	      (merror "Incomplete number"))
	     (T
	      (MAKE-NUMBER (CONS (NREVERSE L) DATA)))))
    (PARSE-TYI)))


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Comment By: Raymond Toy (rtoy)
Date: 2003-05-13 00:17

Message:
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user_id=28849

I think the following replacement in nparse.lisp will catch
these errors.   Help pick out a better error message.

(DEFUN SCAN-DIGITS (DATA CONTINUATION? CONTINUATION)
  (DO ((C (PARSE-TYIPEEK) (PARSE-TYIPEEK))
       (L () (CONS C L)))
      ((NOT (ASCII-NUMBERP C))
       (COND ((IMEMBER C CONTINUATION?)
	      (FUNCALL CONTINUATION (LIST* (NCONS (FIXNUM-CHAR-UPCASE
						   (PARSE-TYI)))
					   (NREVERSE L)
					   Data)
				   ))
	     ((null l)
	      (merror "Incomplete number"))
	     (T
	      (MAKE-NUMBER (CONS (NREVERSE L) DATA)))))
    (PARSE-TYI)))


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Comment By: Barton Willis (willisb)
Date: 2003-05-07 11:14

Message:
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user_id=570592

 Agreed, the internal error is a bug, and I agree that
allowing the exponent to default to zero isn't a good thing.
Should somebody fix this, all three inputs

(C1) 4.2b;
Error: Unexpected end of #<string-input stream from "">.
Fast links are on: do (si::use-fast-links nil) for debugging
Error signalled by MACSYMA-TOP-LEVEL.
Broken at MREAD-RAW.  Type :H for Help.
MAXIMA>>:q
(C1) 4.2d;
(D1) 				     4.2D+
(C2) 4.2e;
(D2) 				     4.2E+

should generate more or less the same (comphensible) error 
message.


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Comment By: Stavros Macrakis (macrakis)
Date: 2003-05-05 18:01

Message:
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user_id=588346

I don't see any good reason to allow "4.2d" etc. as a short 
form of "4.2d0".  This is not supported by any programming 
language I know.  What software allows this???  My guess is 
that it is either (1) some sort of very permissive user front-
end; (2) a fixed format where spaces are interpreted as 
zeroes; or (3) an accident/bug of the implementation.

On the other hand, the error message given is poor.  It should 
give a normal syntax error, not an internal error.  THAT is a 
bug.

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