The sharedvars module is an extension module.  Its purpose is to provide new primitives to the Orchids language.

All variables are thread-local in Orchids: if you use you variable $x in a  rule, then only the current thread sees the values of $x.  The sharedvars module allows one to create the equivalent of global variables, shared by all threads and all rules.

The name is slightly misleading: sharedvars are not variables, they are just entries in a  global hash table.  One creates a sharedvar by using the Set configuration option, or by calling set_shared_var, e.g., set_shared_var("my_database", "orchids.sql") or set_shared_var("last_time_accessed", $time), and other threads can obtain the value by reading get_shared_var("my_database") or get_shared_var("last_time_accessed") respectively.

Configuration options

<module sharedvars>

• HashSize n: defines the size of the global hash size.  Default is 1021.
• Set name value: initialize sharedvar name to the string value (between quotes).

</module>

Primitives

• set_shared_var : str, str → int
  set a sharedvar to a value
  • usage: set_shared_var(var-name, value)
    sets the value of the sharedvar var-name to value, creating it if necessary
  • returns: 1 (true)
• get_shared_var : str → str
  get a sharedvar’s  value
  • usage: get_shared_var(var-name)
  • returns: the value of the sharedvar var-name if it exists, or the undefined null value otherwise
• del_shared_var : str → int
  delete a sharedvar
  • usage: del_shared_var(var-name)
  • returns: 1 (true) if sharedvar var-name was successfully deleted, 0 (false) if sharedvar var-name did not exist