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You can define your own exception types using the dclex
statement:
dclex type
In this statement, type must be a valid MFL
identifier, not used for another constant (see Constants).
The dclex
statement defines a new exception identified by
the constant type and allocates a new exception number for it.
The type can subsequently be used in throw
and
catch
statements, for example:
dclex myrange number fact(number val) returns number do if val < 0 throw myrange "fact argument is out of range" fi … done