# Copyright 2006 Google, Inc. All Rights Reserved.

[0] Fix | Delete

# Licensed to PSF under a Contributor Agreement.

[1] Fix | Delete

[2] Fix | Delete

# A grammar to describe tree matching patterns.

[3] Fix | Delete

# Not shown here:

[4] Fix | Delete

# - 'TOKEN' stands for any token (leaf node)

[5] Fix | Delete

# - 'any' stands for any node (leaf or interior)

[6] Fix | Delete

# With 'any' we can still specify the sub-structure.

[7] Fix | Delete

[8] Fix | Delete

# The start symbol is 'Matcher'.

[9] Fix | Delete

[10] Fix | Delete

Matcher: Alternatives ENDMARKER

[11] Fix | Delete

[12] Fix | Delete

Alternatives: Alternative ('|' Alternative)*

[13] Fix | Delete

[14] Fix | Delete

Alternative: (Unit | NegatedUnit)+

[15] Fix | Delete

[16] Fix | Delete

Unit: [NAME '='] ( STRING [Repeater]

[17] Fix | Delete

| NAME [Details] [Repeater]

[18] Fix | Delete

| '(' Alternatives ')' [Repeater]

[19] Fix | Delete

| '[' Alternatives ']'

[20] Fix | Delete

)

[21] Fix | Delete

[22] Fix | Delete

NegatedUnit: 'not' (STRING | NAME [Details] | '(' Alternatives ')')

[23] Fix | Delete

[24] Fix | Delete

Repeater: '*' | '+' | '{' NUMBER [',' NUMBER] '}'

[25] Fix | Delete

[26] Fix | Delete

Details: '<' Alternatives '>'

[27] Fix | Delete

[28] Fix | Delete