Identifiers

Basic identifiers

Basic identifiers consist of letters, underscores and digits and must start with a letter. They are not case sensitive. Reserved words of the language cannot be basic identifiers. Examples of valid VHDL basic identifiers:

A_myId90
a_MYID90
abcDEf100_1
ABCdef100_1

The two first are equivalent and the two last are also equivalent (case insensitivity).

Examples of invalid basic identifiers:

_not_reset   -- start with underscore
85MHz_clock  -- start with digit
LooP         -- reserved word of the language

Extended identifiers

VHDL extended identifiers are delimited by backslashes (\) and can contain letters, underscores, digits, spaces and other special characters (see the Language Reference Manual for a complete definition of special characters). The sequence of characters between backslashes can be reserved words of the VHDL language. Backslashes can be included in extended identifiers by doubling them (\\). Extended identifiers are case sensitive. Examples of (all different) extended identifiers:

\if\
\If\
\My Identifier\
\An \\ Identifier \\ With \\ Backslashes\
\&#@[]:.*\
\$£§{}\