complex linestyles

Hi,

 

Can somebody explain in detail the parts of a linestyle format e.g.:

*GAS_LINE,Gas line ----GAS----GAS----GAS----GAS----GAS----GAS--

A,12.7,-5.08,["GAS",STANDARD,S=2.54,R=0.0,X=-2.54,Y=-1.27],-6.35

Ik work in mm and I can't find any line segments/spacings with the numbers provided in this format

 

 

Or give a link with such explanation.

Is there a site where one can download user made linestyles?

 

Thank you

 

Stefan