9.2  Using Constraint Handling Rules

Here are the steps to be taken from writing to using CHRs:

• Write a CHR program in a file File.chr.
• In ECLⁱPS^e, load the chr library with the query lib(chr). It contains both the compiler and runtime system for CHRs. Now ECLⁱPS^e is in coroutining mode.
• Compile your chr file into a pl file with the query chr2pl(File).
• In any ECLⁱPS^e session, you can load a compiled constraint handler ([File].). The CHR library is automatically loaded to provide the necessary runtime environment. ECLⁱPS^e is in coroutining mode.

You can compile your chr file and load the resulting pl file at once using the query chr(File).