#### 7.2.60 interest

`(interest (COMMAND [args]))`
  Allows you to express interest in a command. When geomview executes that command in the future it will echo it to the communication pool from which the interest command came. COMMAND can be any command. Args specify restrictions on the values of the arguments; if args are present in the interest command, geomview will only echo calls to the command in which the arguments match those given in the interest command. Two special argument values may appear in the argument list. `*` matches any value. `nil` matches any value but supresses the reporting of that value; its value is reported as `nil`.

  The purpose of the interest command is to allow external modules to find out about things happening inside geomview. For example, a module interested in knowing when a geom called `foo` is deleted could say `(interest (delete foo))` and would receive the string `(delete foo)` when foo is deleted.

  Picking is a special case of this. For most modules interested in pick events the command `(interest (pick world))` is sufficient. This causes geomview to send a string of the form `(pick world ...)` every time a pick event (right mouse double clique). See the `(pick ...)` command for details.