GHOST throwing exception on topics after clearing the atomspace

[Habush]

Let's we have a file containing the following simple ghost topic:

topic: ~introductions keep[]
u: ([hello hi hey] {there}) ^intro()

After opening a guile shell and importing the necessary OpenCog modules, I run the following commands:

scheme@(guile-user) > (ghost-parse-file "chatrules.top")
scheme@(guile-user) > (clear) 

If I try to run ghost-parse-file after clearing the atomspace, then I get the following error:

In ghost.scm:
258:2 4 (ghost-parse-file )
In system/base/lalr.upstream.scm:
1956:16 3 ( _ )
In opencog/ghost/cs-parse.scm:
290:8 2 ( #(0 #t 25 #<lexical-token category: TOPIC source: #<source-location input: "/root/ghost/chatru…> …) …)
In opencog/ghost/translator.scm:
810:2 1 (create-topic _ _ _)
In unknown file:
0 (cog-set-value! (ConceptNode "GHOST introductions")
# #)

This means loading ghost rules that have topics will work fine but it will raise the above exception if we reload the same rules after clearing the atomspace.

What is the cause of this issue? And how can I fix it.

[amebel]

Don't use (clear), OpenPsi doesn't work well with it. Just restart the cogserver.