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How to encode special characters in a launch file <param> element

asked 2011-11-21 00:32:45 -0500

billmania gravatar image

In the following example, I would like to have the value of the parameter "myString" to contain only two ASCII characters: CarriageReturn and LineFeed. How do I specify them in the definition of a parameter in a launch file?

<param name="myString" type="string" value="\r\n"/>

I've searched for the definition for all of the "special characters" but have not yet found the right combination of search terms.

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BTW, what is your actual use case here? I mean, \r\n is not your typical parameter, so I was wondering if there is another way to achieve what you need.
roehling gravatar image roehling  ( 2011-11-22 17:14:35 -0500 )edit

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answered 2011-11-21 19:03:31 -0500

updated 2011-11-21 19:06:28 -0500

Usually, you would encode CR and LF as the XML entities &#13; and &#10; respectively. However, roslaunch trims whitespace (including CR/LF) from the beginning and the end of a parameter string value (which is unfortunate and possibly a bug), and seems to apply the XML end-of-line handling (convert CR+LF and CR to LF) even to these encoded entities (which would be a bug in the XML parser).

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Asked: 2011-11-21 00:32:45 -0500

Seen: 485 times

Last updated: Nov 21 '11