The other day I was programming in Esterel with my favourite editor Vim. And it turned out that I did not have syntax and indent files which would make my life easier while using Esterel.
I could find syntax file for esterel from somewhere, and I modified, indent file for shell scripts to suit for esterel.
You must add following 3 lines to your .vimrc file :
au BufRead,BufNewFile *.strl set filetype=esterel
au! Syntax ESTEREL source /usr/share/vim/vim63/syntax/esterel.vim
:filetype indent on
Change the source where you had put the syntax file for esterel.
Ideally it should go to $VIMRUNTIME/syntax and $VIMRUNTIME/indent respectively.
Anyways, here are the links for the syntax and indent file for esterel.