# Copyright 2006 Google, Inc. All Rights Reserved. # Licensed to PSF under a Contributor Agreement. # A grammar to describe tree matching patterns. # Not shown here: # - 'TOKEN' stands for any token (leaf node) # - 'any' stands for any node (leaf or interior) # With 'any' we can still specify the sub-structure. # The start symbol is 'Matcher'. Matcher: Alternatives ENDMARKER Alternatives: Alternative ('|' Alternative)* Alternative: (Unit | NegatedUnit)+ Unit: [NAME '='] ( STRING [Repeater] | NAME [Details] [Repeater] | '(' Alternatives ')' [Repeater] | '[' Alternatives ']' ) NegatedUnit: 'not' (STRING | NAME [Details] | '(' Alternatives ')') Repeater: '*' | '+' | '{' NUMBER [',' NUMBER] '}' Details: '<' Alternatives '>'