vague `#Illegal value for RHS value`

[garfieldnate]

Try sourcing this:

sp {foo
   (state <s> ^type state)
   -->
    (cmd output command-to-file chunks.soar print --chunks --full)
}

This output is:

#Illegal value for RHS value
(Ignoring production foo)

Production addition failed.

The actual error is that chunks.soar needs to be quoted like so:

sp {foo
   (state <s> ^type state)
   -->
    (cmd output command-to-file |chunks.soar| print --chunks --full)
}

The error message given is very unhelpful. I also don't know why the # character is there. Ideally we would have the line and column number to report the issue, but more it would also be helpful enough to just be told that chunks.soar could not be parsed at this location in the production.