| 1. | Patterns may be nested, and a term is a pattern matching itself. |
| 2. | Edit slots are used as wild cards. |
| 3. | The explode form is used to specify patterns that match terms with non-homogeneous structure, such as various arities, opids, and variations on parameter structure and value. Edit slots in the exploded form that expect a sequence of structures actually match arbitrary sequences of such structures. |
| 4. | There are disjunction, conjunction, and negation expressions that can be used freely on any part of a pattern (including opid and binding variables in the exploded form).
<pattern>|<pattern>, <pattern>|&|<pattern> and |NOT|:<pattern> are the forms. |
| 5. | There are expressions for matching module change of bound variables and for matching against variables (sometimes second-order). In these cases, no further recursive analysis is performed on the pattern.
|CBV|:<pattern> and |VARS|:<pattern> are the forms. |
| 6. | There is a *RECURSE* pattern that may be used within the pattern to match against a term recursively. |
| 7. | There is a pattern [string]:* which can match against any parameter type. |
| 8. | There are patterns [string]:substr, [string]:prefix, and [string]:suffix, for matching against substrings, prefixes, and suffixes of parameter values and opids. |
| 9. | As an abbreviation, the parameter matching forms mentioned in the previous couple of points will also match a term any of whose parameters or binding variables matches the pattern. |