New Features in VHDL 1993
The IEEE Std 1076-1993 IEEE Standard VHDL Language Reference Manual introduced several new syntactical elements to VHDL, including the use of basic identifiers, consistent statement bracketing, and the direct instantiation of a design entity. For complete information on VHDL syntax, refer to the IEEE Standard VHDL Language Reference Manual.
The new keywords available in VHDL 1993 are as follows:
Using any of these keywords as a name in a VHDL file when you compile a project for VHDL 1993 will cause compilation errors.