General

This clause specifies the basic elements from which an EDMexpressX schema is composed: the character set, remarks, symbols, reserved words, identifiers, and literals.
The basic EDMexpressX language elements are the same as those for the EXPRESS language defined in Clause 7 of ISO 10303-11, with the exceptions noted below.
EDMexpressX is a case insensitive language in the same way as the EXPRESS language.

Character Set

EDMexpressX uses exactly the same character set as the EXPRESS language.

Remarks and Comments

EDMexpressX language has exactly the same definition of remarks as in the EXPRESS language.

Symbols

The EDMexpressX^ language defines the following additional symbols, which are not defined in the EXPRESS language

:: ++ += -= &

The symbols have the following meaning:

::	Schema qualifier, e.g. tar::MyEnitity
++	Add/append to aggregate. Elements are added to the aggregate in case the aggregate type is either SET or BAG, and appended to the aggregate if it is of type LIST. Not legal for type ARRAY. The actual element will be unconditionally added to the aggregate, i.e. duplicated SET elements may be a result of the operation. SET and UNIQUE LIST may contain duplicated element values after operation. See also union operator.
+=	Aggregate union. One aggregate becomes the union of itself and another aggregate, e.g. a1 += a2;
-=	Aggregate difference. One aggregate becomes the difference between itself and another aggregate, e.g. a1 -= a2;
&	Is in EDMexpressX^ used as a delimiter between the constituents in a complex entity instead of +, e.g. Man&Woman.

See also: New operators , Assignment Statement and Entity Identifiers Complex Entity type