Hi, Can you suggest some UML diagram drawing tool based on the script similar to http://www.websequencediagrams.com/ which help in drawing sequence diagram only.
Have a look at Umlet: http://www.umlet.com/, select a "Sequence - all in one" diagram. It's a very basic and simple tool, but it works just great.
You may also try Red Koda Community although it's not script-based. For making sequence diagram faster, you can use short cut keys, e.g. Press e is lifeline, press s is synchronouse message, right-click press d to delete an element or line etc. It's quite handy. Have a trial. http://www.redkoda.com/
A full list of this kind of textual UML tools can be found here: http://modeling-languages.com/blog/content/uml-tools-textual-notations-define-uml-models
My best two recommendations right now would be: yUML and PlantUML
If you need something more complex and integrated with Eclipse try TextUML
See EasyUML Editor. It is a Web based UML editor which generates UML from simple textual notation