Package schrodinger :: Package application :: Package desmond :: Package antlr3 :: Module tree :: Class TreeParser

Class TreeParser

                object --+    
                         |    
recognizers.BaseRecognizer --+
                             |
                            TreeParser

@brief Baseclass for generated tree parsers.

A parser for a stream of tree nodes. "tree grammars" result in a subclass of this. All the error reporting and recovery is shared with Parser via the BaseRecognizer superclass.

Instance Methods

[hide private]

__init__(self, input, state=None)
x.__init__(...) initializes x; see help(type(x)) for signature

reset(self)
reset the parser's state; subclasses must rewinds the input stream

setTreeNodeStream(self, input)
Set the input stream

getTreeNodeStream(self)

getSourceName(self)

getCurrentInputSymbol(self, input)
Match needs to return the current input symbol, which gets put into the label for the associated token ref; e.g., x=ID.

getMissingSymbol(self, input, e, expectedTokenType, follow)
Conjure up a missing token during error recovery.

inContext(self, context, adaptor=None, tokenName=None, t=None)
Check if current node in input has a context.

matchAny(self, ignore)
Match '.' in tree parser has special meaning.

mismatch(self, input, ttype, follow)
We have DOWN/UP nodes in the stream that have no line info; override.

getErrorHeader(self, e)
Prefix error message with the grammar name because message is always intended for the programmer because the parser built the input tree not the user.

getErrorMessage(self, e, tokenNames)
Tree parsers parse nodes they usually have a token object as payload.

traceIn(self, ruleName, ruleIndex)

traceOut(self, ruleName, ruleIndex)

Inherited from recognizers.BaseRecognizer: alreadyParsedRule, beginResync, combineFollows, computeContextSensitiveRuleFOLLOW, computeErrorRecoverySet, consumeUntil, displayRecognitionError, emitErrorMessage, endResync, failed, getBacktrackingLevel, getGrammarFileName, getNumberOfSyntaxErrors, getRuleInvocationStack, getRuleMemoization, getTokenErrorDisplay, match, memoize, mismatchIsMissingToken, mismatchIsUnwantedToken, recover, recoverFromMismatchedSet, recoverFromMismatchedToken, reportError, setBacktrackingLevel, setInput, toStrings

Inherited from object: __delattr__, __format__, __getattribute__, __hash__, __new__, __reduce__, __reduce_ex__, __repr__, __setattr__, __sizeof__, __str__, __subclasshook__

Class Methods

[hide private]

_inContext(cls, adaptor, tokenNames, t, context)
The worker for inContext.

Inherited from recognizers.BaseRecognizer (private): _getRuleInvocationStack

Static Methods

[hide private]

_getAncestor(adaptor, tokenNames, t, goal)
Helper for static inContext.

Class Variables

[hide private]

dotdot = '.*[^.]\\.\\.[^.].*'

doubleEtc = '.*\\.\\.\\.\\s+\\.\\.\\..*'

dotdotPattern = re.compile(r'.*[^\.]\.\.[^\.].*')

doubleEtcPattern = re.compile(r'.*\.\.\.\s+\.\.\..*')

Inherited from recognizers.BaseRecognizer: DEFAULT_TOKEN_CHANNEL, HIDDEN, MEMO_RULE_FAILED, MEMO_RULE_UNKNOWN, antlr_version, antlr_version_str, tokenNames

Properties

[hide private]

Inherited from object: __class__

Method Details

[hide private]

init(self, input, state=None)
(Constructor)

x.__init__(...) initializes x; see help(type(x)) for signature

Overrides: object.__init__: (inherited documentation)

reset(self)

reset the parser's state; subclasses must rewinds the input stream

Overrides: recognizers.BaseRecognizer.reset: (inherited documentation)

getSourceName(self)

Overrides: recognizers.BaseRecognizer.getSourceName

getCurrentInputSymbol(self, input)

Match needs to return the current input symbol, which gets put into the label for the associated token ref; e.g., x=ID. Token and tree parsers need to return different objects. Rather than test for input stream type or change the IntStream interface, I use a simple method to ask the recognizer to tell me what the current input symbol is.

This is ignored for lexers.

Overrides: recognizers.BaseRecognizer.getCurrentInputSymbol: (inherited documentation)

getMissingSymbol(self, input, e, expectedTokenType, follow)

Conjure up a missing token during error recovery.

The recognizer attempts to recover from single missing
symbols. But, actions might refer to that missing symbol.
For example, x=ID {f($x);}. The action clearly assumes
that there has been an identifier matched previously and that
$x points at that token. If that token is missing, but
the next token in the stream is what we want we assume that
this token is missing and we keep going. Because we
have to return some token to replace the missing token,
we have to conjure one up. This method gives the user control
over the tokens returned for missing tokens. Mostly,
you will want to create something special for identifier
tokens. For literals such as '{' and ',', the default
action in the parser or tree parser works. It simply creates
a CommonToken of the appropriate type. The text will be the token.
If you change what tokens must be created by the lexer,
override this method to create the appropriate tokens.

Overrides: recognizers.BaseRecognizer.getMissingSymbol: (inherited documentation)

inContext(self, context, adaptor=None, tokenName=None, t=None)

Check if current node in input has a context.

Context means sequence of nodes towards root of tree. For example, you might say context is "MULT" which means my parent must be MULT. "CLASS VARDEF" says current node must be child of a VARDEF and whose parent is a CLASS node. You can use "..." to mean zero-or-more nodes. "METHOD ... VARDEF" means my parent is VARDEF and somewhere above that is a METHOD node. The first node in the context is not necessarily the root. The context matcher stops matching and returns true when it runs out of context. There is no way to force the first node to be the root.

_inContext(cls, adaptor, tokenNames, t, context)
Class Method

The worker for inContext.

It's static and full of parameters for testing purposes.

matchAny(self, ignore)

Match '.' in tree parser has special meaning. Skip node or entire tree if node has children. If children, scan until corresponding UP node.

Overrides: recognizers.BaseRecognizer.matchAny

mismatch(self, input, ttype, follow)

We have DOWN/UP nodes in the stream that have no line info; override. plus we want to alter the exception type. Don't try to recover from tree parser errors inline...

getErrorHeader(self, e)

Prefix error message with the grammar name because message is always intended for the programmer because the parser built the input tree not the user.