A name need not contain more than one character. The initial character might be followed by an indefinite number of these characters. An implementation might use only the first 31 characters when comparing names. An implementation might use only the first six characters and ignore the difference in case between a and A when comparing names with external linkage from separate translation units. Names beginning with an underscore are generally reserved for use by an implementation.
Some diagrams require boxes that permit anything except one or a few items.
In these cases, bold text describes the matching rule. For example, not NL matches any character except a newline character. All rights reserved.