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Members or Ranges

Lists the members of the class as code points (xxx) or as ranges of code points (xxx-yyy). Any class too numerous to list in full is elided with "...".

Tag=ttt

An anonymous class implicitly defined based on tag value.

[: :] - named character set

Reference to a named character set [:name:].

(���,���,\,���) - set operators

Sets may be combined by set operators (��� = intersection, ��� = union, \ = difference, ��� = symmetric difference).

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Used as Trigger

This rule triggers one of the actions listed below.

Used as Context

This rule defines a required context for a code point.

Anchor

This has a placeholder for the code point for which it is evaluated.

Regular Expression

A regular expression equivalent to the rule, shown in the standard notation with some extensions as noted:

��� - context anchor

In a regex the ��� signifies a placeholder for the actual code point, when a context is evaluated. The code point must occur at the position corresponding to the anchor. Rules containing an anchor cannot be used as triggers.

(...)��� - look-behind

If present encloses required context preceding the anchor.

���(...) - look-ahead

If present encloses required context following the anchor.

(: :) - rule reference

Non-recursive reference to a named rule.

[: :] - character set either named, implicit or property

Reference to a named character set [:name:], an implicit character set [:class tag=val:] or a given Unicode property [:class property:prop=val:]. A leading "^" before name or tag indicates the set complement.

(|) - choice operator

When there are various choices in a rule, choices are separated by the set operator (|) and each choice is represented by a set enclosed in parenthesis.

(���,���,\,���) - set operators

Sets may be combined by set operators (��� = intersection, ��� = union, \ = difference, ��� = symmetric difference).

�� - empty set

Indicated that the following set is empty because of the result of set operations or because non of its elements are part of the repertoire defined here.

An empty set that is not optional means that a rule can never match.

{m}, {m, n}, {m,} - count

Indicates that the preceding element is evaluated from m to n times. Only {m} means the preceding element is evaluated exactly m times (equivalent to {m,m}), {m,} means the preceding element is evaluated at least m times.

No count indicated the elements is evaluated once (equivalent to "{1}").

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{...} - variant type set

In the "Rule/Variant Set" column the notation {...} means a set of variant types.