comp.lang.idl-pvwave archive: archive » Re: A simple DLM question

Home » Public Forums » archive » Re: A simple DLM question

Show: Today's Messages :: Show Polls :: Message Navigator
E-mail to friend

Re: A simple DLM question [message #81216 is a reply to message #81215]

Wed, 29 August 2012 10:31

Lajos Foldy
Messages: 176
Registered: December 2011

Senior Member

On Wednesday, August 29, 2012 6:23:51 PM UTC+2, Xin Tao wrote:

> That's very clear explanation, thanks. But I would still say that it's not very intuitive to me that 3 is a constant but -3 is not.

A '-' can be both unary (-3) and binary (a-3). Including the '-' in the constant would be erroneous in the binary case and you would get a syntax error.

There is a similar feature (or bug?) in parsing the exponent of floating point literals. IDL accepts 1e- as a valid float number:

IDL> help, 1e-
<Expression> FLOAT = 1.00000

But this results in a syntax error for expressions like 1e-a:

IDL> a=0 & help, 1e-a

a=0 & help, 1e-a
^
% Syntax error.

(I think 1e- should be invalid and 1e-a should be valid.)

regards,
Lajos

Report message to a moderator

[Message index]

		Re: A simple DLM question By: Michael Galloy on Wed, 29 August 2012 11:16
		Re: A simple DLM question By: chris_torrence@NOSPAM on Wed, 29 August 2012 10:50
		Re: A simple DLM question By: Lajos Foldy on Wed, 29 August 2012 10:31
		Re: A simple DLM question By: Xin Tao on Wed, 29 August 2012 09:23
		Re: A simple DLM question By: chris_torrence@NOSPAM on Wed, 29 August 2012 08:55
		Re: A simple DLM question By: Xin Tao on Tue, 28 August 2012 22:03
		Re: A simple DLM question By: Craig Markwardt on Tue, 28 August 2012 18:10
		Re: A simple DLM question By: Xin Tao on Tue, 28 August 2012 14:16
		Re: A simple DLM question By: Jim Pendleton on Tue, 28 August 2012 09:06
		Re: A simple DLM question By: Xin Tao on Mon, 27 August 2012 15:08
		Re: A simple DLM question By: Xin Tao on Mon, 27 August 2012 15:04
		Re: A simple DLM question By: Craig Markwardt on Mon, 27 August 2012 13:51
		Re: A simple DLM question By: Jim Pendleton on Mon, 27 August 2012 13:48

Previous Topic:	Tasselated Cap in IDL?
Next Topic:	Re: Succinct way of testing array membership

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Sat Oct 11 15:28:57 PDT 2025

Total time taken to generate the page: 2.40080 seconds