Get an identifier for an expression.
A parse of the the expression is attempted, and if successful an identifier is returned. If the parse fails
an error status is raised.
CALL CAT_EIDNT (CI, EXPR; EI; STATUS)
Identifier to the catalogue to which the expression refers.
EI = INTEGER (Returned)
Identifier to the expression.
INTEGER (Given and Returned)
The global status.
Copyright (C) 1999 Central
Laboratory of the Research Councils