Is there an xbasic function to parse out the value(s) held in e.tmpl.linkdefinition into a pointer variable or something?

When my child grid opens I need to extract the parent's primary key value for the record being displayed. The "linkDefinition" string contains something like: "Member_id(C|!|M00250)"

I could parse it myself, but what if A5 changes the format of the linkDefinition string again? The wikipedia shows the string as being formatted a bit different than what I'm seeing in version 11. Wiki doesn't say anything about the "!" between the field type and field value. Wiki says:

The syntax for the linkDefinition is a comma delimited list of link definitions in this format: linkField(type:linkValue)

Examples:

tmpl.linkDefinition = "invoice_number(N:1023)"
tmpl.linkDefinition = "first_name(c:john),lastname(c:smith)"