"""ANTLR3 runtime package""" # begin[licence] # # [The "BSD licence"] # Copyright (c) 2005-2012 Terence Parr # All rights reserved. # # Redistribution and use in source and binary forms, with or without # modification, are permitted provided that the following conditions # are met: # 1. Redistributions of source code must retain the above copyright # notice, this list of conditions and the following disclaimer. # 2. Redistributions in binary form must reproduce the above copyright # notice, this list of conditions and the following disclaimer in the # documentation and/or other materials provided with the distribution. # 3. The name of the author may not be used to endorse or promote products # derived from this software without specific prior written permission. # # THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR # IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES # OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. # IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, # INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT # NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF # THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. # # end[licence] from io import StringIO from .constants import DEFAULT_CHANNEL, EOF from .tokens import Token ############################################################################ # # basic interfaces # IntStream # +- CharStream # \- TokenStream # # subclasses must implemented all methods # ############################################################################ class IntStream(object): """ @brief Base interface for streams of integer values. A simple stream of integers used when all I care about is the char or token type sequence (such as interpretation). """ def consume(self): raise NotImplementedError def LA(self, i): """Get int at current input pointer + i ahead where i=1 is next int. Negative indexes are allowed. LA(-1) is previous token (token just matched). LA(-i) where i is before first token should yield -1, invalid char / EOF. """ raise NotImplementedError def mark(self): """ Tell the stream to start buffering if it hasn't already. Return current input position, index(), or some other marker so that when passed to rewind() you get back to the same spot. rewind(mark()) should not affect the input cursor. The Lexer track line/col info as well as input index so its markers are not pure input indexes. Same for tree node streams. """ raise NotImplementedError def index(self): """ Return the current input symbol index 0..n where n indicates the last symbol has been read. The index is the symbol about to be read not the most recently read symbol. """ raise NotImplementedError def rewind(self, marker=None): """ Reset the stream so that next call to index would return marker. The marker will usually be index() but it doesn't have to be. It's just a marker to indicate what state the stream was in. This is essentially calling release() and seek(). If there are markers created after this marker argument, this routine must unroll them like a stack. Assume the state the stream was in when this marker was created. If marker is None: Rewind to the input position of the last marker. Used currently only after a cyclic DFA and just before starting a sem/syn predicate to get the input position back to the start of the decision. Do not "pop" the marker off the state. mark(i) and rewind(i) should balance still. It is like invoking rewind(last marker) but it should not "pop" the marker off. It's like seek(last marker's input position). """ raise NotImplementedError def release(self, marker=None): """ You may want to commit to a backtrack but don't want to force the stream to keep bookkeeping objects around for a marker that is no longer necessary. This will have the same behavior as rewind() except it releases resources without the backward seek. This must throw away resources for all markers back to the marker argument. So if you're nested 5 levels of mark(), and then release(2) you have to release resources for depths 2..5. """ raise NotImplementedError def seek(self, index): """ Set the input cursor to the position indicated by index. This is normally used to seek ahead in the input stream. No buffering is required to do this unless you know your stream will use seek to move backwards such as when backtracking. This is different from rewind in its multi-directional requirement and in that its argument is strictly an input cursor (index). For char streams, seeking forward must update the stream state such as line number. For seeking backwards, you will be presumably backtracking using the mark/rewind mechanism that restores state and so this method does not need to update state when seeking backwards. Currently, this method is only used for efficient backtracking using memoization, but in the future it may be used for incremental parsing. The index is 0..n-1. A seek to position i means that LA(1) will return the ith symbol. So, seeking to 0 means LA(1) will return the first element in the stream. """ raise NotImplementedError def size(self): """ Only makes sense for streams that buffer everything up probably, but might be useful to display the entire stream or for testing. This value includes a single EOF. """ raise NotImplementedError def getSourceName(self): """ Where are you getting symbols from? Normally, implementations will pass the buck all the way to the lexer who can ask its input stream for the file name or whatever. """ raise NotImplementedError class CharStream(IntStream): """ @brief A source of characters for an ANTLR lexer. This is an abstract class that must be implemented by a subclass. """ # pylint does not realize that this is an interface, too #pylint: disable-msg=W0223 EOF = -1 def __init__(self): # line number 1..n within the input self._line = 1 # The index of the character relative to the beginning of the # line 0..n-1 self._charPositionInLine = 0 def substring(self, start, stop): """ For infinite streams, you don't need this; primarily I'm providing a useful interface for action code. Just make sure actions don't use this on streams that don't support it. """ raise NotImplementedError def LT(self, i): """ Get the ith character of lookahead. This is the same usually as LA(i). This will be used for labels in the generated lexer code. I'd prefer to return a char here type-wise, but it's probably better to be 32-bit clean and be consistent with LA. """ raise NotImplementedError @property def line(self): """ANTLR tracks the line information automatically""" return self._line @line.setter def line(self, value): """ Because this stream can rewind, we need to be able to reset the line """ self._line = value @property def charPositionInLine(self): """ The index of the character relative to the beginning of the line 0..n-1 """ return self._charPositionInLine @charPositionInLine.setter def charPositionInLine(self, pos): self._charPositionInLine = pos class TokenStream(IntStream): """ @brief A stream of tokens accessing tokens from a TokenSource This is an abstract class that must be implemented by a subclass. """ # pylint does not realize that this is an interface, too #pylint: disable-msg=W0223 def LT(self, k): """ Get Token at current input pointer + i ahead where i=1 is next Token. i<0 indicates tokens in the past. So -1 is previous token and -2 is two tokens ago. LT(0) is undefined. For i>=n, return Token.EOFToken. Return null for LT(0) and any index that results in an absolute address that is negative. """ raise NotImplementedError def range(self): """ How far ahead has the stream been asked to look? The return value is a valid index from 0..n-1. """ raise NotImplementedError def get(self, i): """ Get a token at an absolute index i; 0..n-1. This is really only needed for profiling and debugging and token stream rewriting. If you don't want to buffer up tokens, then this method makes no sense for you. Naturally you can't use the rewrite stream feature. I believe DebugTokenStream can easily be altered to not use this method, removing the dependency. """ raise NotImplementedError def getTokenSource(self): """ Where is this stream pulling tokens from? This is not the name, but the object that provides Token objects. """ raise NotImplementedError def toString(self, start=None, stop=None): """ Return the text of all tokens from start to stop, inclusive. If the stream does not buffer all the tokens then it can just return "" or null; Users should not access $ruleLabel.text in an action of course in that case. Because the user is not required to use a token with an index stored in it, we must provide a means for two token objects themselves to indicate the start/end location. Most often this will just delegate to the other toString(int,int). This is also parallel with the TreeNodeStream.toString(Object,Object). """ raise NotImplementedError ############################################################################ # # character streams for use in lexers # CharStream # \- ANTLRStringStream # ############################################################################ class ANTLRStringStream(CharStream): """ @brief CharStream that pull data from a unicode string. A pretty quick CharStream that pulls all data from an array directly. Every method call counts in the lexer. """ def __init__(self, data): """ @param data This should be a unicode string holding the data you want to parse. If you pass in a byte string, the Lexer will choke on non-ascii data. """ super().__init__() # The data being scanned self.strdata = str(data) self.data = [ord(c) for c in self.strdata] # How many characters are actually in the buffer self.n = len(data) # 0..n-1 index into string of next char self.p = 0 # A list of CharStreamState objects that tracks the stream state # values line, charPositionInLine, and p that can change as you # move through the input stream. Indexed from 0..markDepth-1. self._markers = [ ] self.lastMarker = None self.markDepth = 0 # What is name or source of this char stream? self.name = None def reset(self): """ Reset the stream so that it's in the same state it was when the object was created *except* the data array is not touched. """ self.p = 0 self._line = 1 self.charPositionInLine = 0 self._markers = [ ] self.lastMarker = None self.markDepth = 0 def consume(self): if self.p < self.n: if self.data[self.p] == 10: # ord('\n') self._line += 1 self.charPositionInLine = 0 else: self.charPositionInLine += 1 self.p += 1 # else we reached EOF # just do nothing def LA(self, i): if i == 0: return 0 # undefined if i < 0: i += 1 # e.g., translate LA(-1) to use offset i=0; then data[p+0-1] if self.p + i - 1 < self.n: return self.data[self.p + i - 1] else: return EOF def LT(self, i): if i == 0: return 0 # undefined if i < 0: i += 1 # e.g., translate LA(-1) to use offset i=0; then data[p+0-1] if self.p + i - 1 < self.n: return self.strdata[self.p + i - 1] else: return EOF def index(self): """ Return the current input symbol index 0..n where n indicates the last symbol has been read. The index is the index of char to be returned from LA(1). """ return self.p def size(self): return self.n def mark(self): state = (self.p, self.line, self.charPositionInLine) if self.markDepth < len(self._markers): self._markers[self.markDepth] = state else: self._markers.append(state) self.markDepth += 1 self.lastMarker = self.markDepth return self.lastMarker def rewind(self, marker=None): if marker is None: marker = self.lastMarker p, line, charPositionInLine = self._markers[marker - 1] self.seek(p) self._line = line self.charPositionInLine = charPositionInLine self.release(marker) def release(self, marker=None): if marker is None: marker = self.lastMarker self.markDepth = marker - 1 def seek(self, index): """ consume() ahead until p==index; can't just set p=index as we must update line and charPositionInLine. """ if index <= self.p: self.p = index # just jump; don't update stream state (line, ...) return # seek forward, consume until p hits index while self.p < index: self.consume() def substring(self, start, stop): return self.strdata[start:stop + 1] def getSourceName(self): return self.name class ANTLRFileStream(ANTLRStringStream): """ @brief CharStream that opens a file to read the data. This is a char buffer stream that is loaded from a file all at once when you construct the object. """ def __init__(self, fileName): """ @param fileName The path to the file to be opened. The file will be opened with mode 'r'. """ self._fileName = fileName with open(fileName, 'r') as fp: super().__init__(fp.read()) @property def fileName(self): return self._fileName class ANTLRInputStream(ANTLRStringStream): """ @brief CharStream that reads data from a file-like object. This is a char buffer stream that is loaded from a file like object all at once when you construct the object. All input is consumed from the file, but it is not closed. """ def __init__(self, file): """ @param file A file-like object holding your input. Only the read() method must be implemented. """ data = file.read() super().__init__(data) # I guess the ANTLR prefix exists only to avoid a name clash with some Java # mumbojumbo. A plain "StringStream" looks better to me, which should be # the preferred name in Python. StringStream = ANTLRStringStream FileStream = ANTLRFileStream InputStream = ANTLRInputStream ############################################################################ # # Token streams # TokenStream # +- CommonTokenStream # \- TokenRewriteStream # ############################################################################ class CommonTokenStream(TokenStream): """ @brief The most common stream of tokens The most common stream of tokens is one where every token is buffered up and tokens are prefiltered for a certain channel (the parser will only see these tokens and cannot change the filter channel number during the parse). """ def __init__(self, tokenSource=None, channel=DEFAULT_CHANNEL): """ @param tokenSource A TokenSource instance (usually a Lexer) to pull the tokens from. @param channel Skip tokens on any channel but this one; this is how we skip whitespace... """ super().__init__() self.tokenSource = tokenSource # Record every single token pulled from the source so we can reproduce # chunks of it later. self.tokens = [] # Map to override some Tokens' channel numbers self.channelOverrideMap = {} # Set; discard any tokens with this type self.discardSet = set() # Skip tokens on any channel but this one; this is how we skip # whitespace... self.channel = channel # By default, track all incoming tokens self.discardOffChannelTokens = False # The index into the tokens list of the current token (next token # to consume). p==-1 indicates that the tokens list is empty self.p = -1 # Remember last marked position self.lastMarker = None # how deep have we gone? self._range = -1 def makeEOFToken(self): return self.tokenSource.makeEOFToken() def setTokenSource(self, tokenSource): """Reset this token stream by setting its token source.""" self.tokenSource = tokenSource self.tokens = [] self.p = -1 self.channel = DEFAULT_CHANNEL def reset(self): self.p = 0 self.lastMarker = None def fillBuffer(self): """ Load all tokens from the token source and put in tokens. This is done upon first LT request because you might want to set some token type / channel overrides before filling buffer. """ index = 0 t = self.tokenSource.nextToken() while t and t.type != EOF: discard = False if self.discardSet and t.type in self.discardSet: discard = True elif self.discardOffChannelTokens and t.channel != self.channel: discard = True # is there a channel override for token type? if t.type in self.channelOverrideMap: overrideChannel = self.channelOverrideMap[t.type] if overrideChannel == self.channel: t.channel = overrideChannel else: discard = True if not discard: t.index = index self.tokens.append(t) index += 1 t = self.tokenSource.nextToken() # leave p pointing at first token on channel self.p = 0 self.p = self.skipOffTokenChannels(self.p) def consume(self): """ Move the input pointer to the next incoming token. The stream must become active with LT(1) available. consume() simply moves the input pointer so that LT(1) points at the next input symbol. Consume at least one token. Walk past any token not on the channel the parser is listening to. """ if self.p < len(self.tokens): self.p += 1 self.p = self.skipOffTokenChannels(self.p) # leave p on valid token def skipOffTokenChannels(self, i): """ Given a starting index, return the index of the first on-channel token. """ n = len(self.tokens) while i < n and self.tokens[i].channel != self.channel: i += 1 return i def skipOffTokenChannelsReverse(self, i): while i >= 0 and self.tokens[i].channel != self.channel: i -= 1 return i def setTokenTypeChannel(self, ttype, channel): """ A simple filter mechanism whereby you can tell this token stream to force all tokens of type ttype to be on channel. For example, when interpreting, we cannot exec actions so we need to tell the stream to force all WS and NEWLINE to be a different, ignored channel. """ self.channelOverrideMap[ttype] = channel def discardTokenType(self, ttype): self.discardSet.add(ttype) def getTokens(self, start=None, stop=None, types=None): """ Given a start and stop index, return a list of all tokens in the token type set. Return None if no tokens were found. This method looks at both on and off channel tokens. """ if self.p == -1: self.fillBuffer() if stop is None or stop > len(self.tokens): stop = len(self.tokens) if start is None or start < 0: start = 0 if start > stop: return None if isinstance(types, int): # called with a single type, wrap into set types = set([types]) filteredTokens = [ token for token in self.tokens[start:stop] if types is None or token.type in types ] if len(filteredTokens) == 0: return None return filteredTokens def LT(self, k): """ Get the ith token from the current position 1..n where k=1 is the first symbol of lookahead. """ if self.p == -1: self.fillBuffer() if k == 0: return None if k < 0: return self.LB(-k) i = self.p n = 1 # find k good tokens while n < k: # skip off-channel tokens i = self.skipOffTokenChannels(i + 1) # leave p on valid token n += 1 if i > self._range: self._range = i if i < len(self.tokens): return self.tokens[i] else: return self.makeEOFToken() def LB(self, k): """Look backwards k tokens on-channel tokens""" if self.p == -1: self.fillBuffer() if k == 0: return None if self.p - k < 0: return None i = self.p n = 1 # find k good tokens looking backwards while n <= k: # skip off-channel tokens i = self.skipOffTokenChannelsReverse(i - 1) # leave p on valid token n += 1 if i < 0: return None return self.tokens[i] def get(self, i): """ Return absolute token i; ignore which channel the tokens are on; that is, count all tokens not just on-channel tokens. """ return self.tokens[i] def slice(self, start, stop): if self.p == -1: self.fillBuffer() if start < 0 or stop < 0: return None return self.tokens[start:stop + 1] def LA(self, i): return self.LT(i).type def mark(self): self.lastMarker = self.index() return self.lastMarker def release(self, marker=None): # no resources to release pass def size(self): return len(self.tokens) def range(self): return self._range def index(self): return self.p def rewind(self, marker=None): if marker is None: marker = self.lastMarker self.seek(marker) def seek(self, index): self.p = index def getTokenSource(self): return self.tokenSource def getSourceName(self): return self.tokenSource.getSourceName() def toString(self, start=None, stop=None): """Returns a string of all tokens between start and stop (inclusive).""" if self.p == -1: self.fillBuffer() if start is None: start = 0 elif not isinstance(start, int): start = start.index if stop is None: stop = len(self.tokens) - 1 elif not isinstance(stop, int): stop = stop.index if stop >= len(self.tokens): stop = len(self.tokens) - 1 return ''.join([t.text for t in self.tokens[start:stop + 1]]) class RewriteOperation(object): """@brief Internal helper class.""" def __init__(self, stream, index, text): self.stream = stream # What index into rewrites List are we? self.instructionIndex = None # Token buffer index. self.index = index self.text = text def execute(self, buf): """Execute the rewrite operation by possibly adding to the buffer. Return the index of the next token to operate on. """ return self.index def toString(self): opName = self.__class__.__name__ return '<{opName}@{0.index}:"{0.text}">'.format(self, opName=opName) __str__ = toString __repr__ = toString class InsertBeforeOp(RewriteOperation): """@brief Internal helper class.""" def execute(self, buf): buf.write(self.text) if self.stream.tokens[self.index].type != EOF: buf.write(self.stream.tokens[self.index].text) return self.index + 1 class ReplaceOp(RewriteOperation): """ @brief Internal helper class. I'm going to try replacing range from x..y with (y-x)+1 ReplaceOp instructions. """ def __init__(self, stream, first, last, text): super().__init__(stream, first, text) self.lastIndex = last def execute(self, buf): if self.text is not None: buf.write(self.text) return self.lastIndex + 1 def toString(self): if self.text is None: return ''.format(self) return ''.format(self) __str__ = toString __repr__ = toString class TokenRewriteStream(CommonTokenStream): """@brief CommonTokenStream that can be modified. Useful for dumping out the input stream after doing some augmentation or other manipulations. You can insert stuff, replace, and delete chunks. Note that the operations are done lazily--only if you convert the buffer to a String. This is very efficient because you are not moving data around all the time. As the buffer of tokens is converted to strings, the toString() method(s) check to see if there is an operation at the current index. If so, the operation is done and then normal String rendering continues on the buffer. This is like having multiple Turing machine instruction streams (programs) operating on a single input tape. :) Since the operations are done lazily at toString-time, operations do not screw up the token index values. That is, an insert operation at token index i does not change the index values for tokens i+1..n-1. Because operations never actually alter the buffer, you may always get the original token stream back without undoing anything. Since the instructions are queued up, you can easily simulate transactions and roll back any changes if there is an error just by removing instructions. For example, CharStream input = new ANTLRFileStream("input"); TLexer lex = new TLexer(input); TokenRewriteStream tokens = new TokenRewriteStream(lex); T parser = new T(tokens); parser.startRule(); Then in the rules, you can execute Token t,u; ... input.insertAfter(t, "text to put after t");} input.insertAfter(u, "text after u");} System.out.println(tokens.toString()); Actually, you have to cast the 'input' to a TokenRewriteStream. :( You can also have multiple "instruction streams" and get multiple rewrites from a single pass over the input. Just name the instruction streams and use that name again when printing the buffer. This could be useful for generating a C file and also its header file--all from the same buffer: tokens.insertAfter("pass1", t, "text to put after t");} tokens.insertAfter("pass2", u, "text after u");} System.out.println(tokens.toString("pass1")); System.out.println(tokens.toString("pass2")); If you don't use named rewrite streams, a "default" stream is used as the first example shows. """ DEFAULT_PROGRAM_NAME = "default" MIN_TOKEN_INDEX = 0 def __init__(self, tokenSource=None, channel=DEFAULT_CHANNEL): super().__init__(tokenSource, channel) # You may have multiple, named streams of rewrite operations. # I'm calling these things "programs." # Maps String (name) -> rewrite (List) self.programs = {} self.programs[self.DEFAULT_PROGRAM_NAME] = [] # Map String (program name) -> Integer index self.lastRewriteTokenIndexes = {} def rollback(self, *args): """ Rollback the instruction stream for a program so that the indicated instruction (via instructionIndex) is no longer in the stream. UNTESTED! """ if len(args) == 2: programName = args[0] instructionIndex = args[1] elif len(args) == 1: programName = self.DEFAULT_PROGRAM_NAME instructionIndex = args[0] else: raise TypeError("Invalid arguments") p = self.programs.get(programName) if p: self.programs[programName] = ( p[self.MIN_TOKEN_INDEX:instructionIndex]) def deleteProgram(self, programName=DEFAULT_PROGRAM_NAME): """Reset the program so that no instructions exist""" self.rollback(programName, self.MIN_TOKEN_INDEX) def insertAfter(self, *args): if len(args) == 2: programName = self.DEFAULT_PROGRAM_NAME index = args[0] text = args[1] elif len(args) == 3: programName = args[0] index = args[1] text = args[2] else: raise TypeError("Invalid arguments") if isinstance(index, Token): # index is a Token, grap the stream index from it index = index.index # to insert after, just insert before next index (even if past end) self.insertBefore(programName, index + 1, text) def insertBefore(self, *args): if len(args) == 2: programName = self.DEFAULT_PROGRAM_NAME index = args[0] text = args[1] elif len(args) == 3: programName = args[0] index = args[1] text = args[2] else: raise TypeError("Invalid arguments") if isinstance(index, Token): # index is a Token, grab the stream index from it index = index.index op = InsertBeforeOp(self, index, text) rewrites = self.getProgram(programName) op.instructionIndex = len(rewrites) rewrites.append(op) def replace(self, *args): if len(args) == 2: programName = self.DEFAULT_PROGRAM_NAME first = args[0] last = args[0] text = args[1] elif len(args) == 3: programName = self.DEFAULT_PROGRAM_NAME first = args[0] last = args[1] text = args[2] elif len(args) == 4: programName = args[0] first = args[1] last = args[2] text = args[3] else: raise TypeError("Invalid arguments") if isinstance(first, Token): # first is a Token, grap the stream index from it first = first.index if isinstance(last, Token): # last is a Token, grap the stream index from it last = last.index if first > last or first < 0 or last < 0 or last >= len(self.tokens): raise ValueError( "replace: range invalid: {}..{} (size={})" .format(first, last, len(self.tokens))) op = ReplaceOp(self, first, last, text) rewrites = self.getProgram(programName) op.instructionIndex = len(rewrites) rewrites.append(op) def delete(self, *args): self.replace(*(list(args) + [None])) def getLastRewriteTokenIndex(self, programName=DEFAULT_PROGRAM_NAME): return self.lastRewriteTokenIndexes.get(programName, -1) def setLastRewriteTokenIndex(self, programName, i): self.lastRewriteTokenIndexes[programName] = i def getProgram(self, name): p = self.programs.get(name) if not p: p = self.initializeProgram(name) return p def initializeProgram(self, name): p = [] self.programs[name] = p return p def toOriginalString(self, start=None, end=None): if self.p == -1: self.fillBuffer() if start is None: start = self.MIN_TOKEN_INDEX if end is None: end = self.size() - 1 buf = StringIO() i = start while i >= self.MIN_TOKEN_INDEX and i <= end and i < len(self.tokens): if self.get(i).type != EOF: buf.write(self.get(i).text) i += 1 return buf.getvalue() def toString(self, *args): if self.p == -1: self.fillBuffer() if len(args) == 0: programName = self.DEFAULT_PROGRAM_NAME start = self.MIN_TOKEN_INDEX end = self.size() - 1 elif len(args) == 1: programName = args[0] start = self.MIN_TOKEN_INDEX end = self.size() - 1 elif len(args) == 2: programName = self.DEFAULT_PROGRAM_NAME start = args[0] end = args[1] if start is None: start = self.MIN_TOKEN_INDEX elif not isinstance(start, int): start = start.index if end is None: end = len(self.tokens) - 1 elif not isinstance(end, int): end = end.index # ensure start/end are in range if end >= len(self.tokens): end = len(self.tokens) - 1 if start < 0: start = 0 rewrites = self.programs.get(programName) if not rewrites: # no instructions to execute return self.toOriginalString(start, end) buf = StringIO() # First, optimize instruction stream indexToOp = self.reduceToSingleOperationPerIndex(rewrites) # Walk buffer, executing instructions and emitting tokens i = start while i <= end and i < len(self.tokens): # remove so any left have index size-1 op = indexToOp.pop(i, None) t = self.tokens[i] if op is None: # no operation at that index, just dump token if t.type != EOF: buf.write(t.text) i += 1 # move to next token else: i = op.execute(buf) # execute operation and skip # include stuff after end if it's last index in buffer # So, if they did an insertAfter(lastValidIndex, "foo"), include # foo if end == lastValidIndex. if end == len(self.tokens) - 1: # Scan any remaining operations after last token # should be included (they will be inserts). for i, op in sorted(indexToOp.items()): if op.index >= len(self.tokens) - 1: buf.write(op.text) return buf.getvalue() __str__ = toString def reduceToSingleOperationPerIndex(self, rewrites): """ We need to combine operations and report invalid operations (like overlapping replaces that are not completed nested). Inserts to same index need to be combined etc... Here are the cases: I.i.u I.j.v leave alone, nonoverlapping I.i.u I.i.v combine: Iivu R.i-j.u R.x-y.v | i-j in x-y delete first R R.i-j.u R.i-j.v delete first R R.i-j.u R.x-y.v | x-y in i-j ERROR R.i-j.u R.x-y.v | boundaries overlap ERROR Delete special case of replace (text==null): D.i-j.u D.x-y.v | boundaries overlapcombine to max(min)..max(right) I.i.u R.x-y.v | i in (x+1)-ydelete I (since insert before we're not deleting i) I.i.u R.x-y.v | i not in (x+1)-yleave alone, nonoverlapping R.x-y.v I.i.u | i in x-y ERROR R.x-y.v I.x.u R.x-y.uv (combine, delete I) R.x-y.v I.i.u | i not in x-y leave alone, nonoverlapping I.i.u = insert u before op @ index i R.x-y.u = replace x-y indexed tokens with u First we need to examine replaces. For any replace op: 1. wipe out any insertions before op within that range. 2. Drop any replace op before that is contained completely within that range. 3. Throw exception upon boundary overlap with any previous replace. Then we can deal with inserts: 1. for any inserts to same index, combine even if not adjacent. 2. for any prior replace with same left boundary, combine this insert with replace and delete this replace. 3. throw exception if index in same range as previous replace Don't actually delete; make op null in list. Easier to walk list. Later we can throw as we add to index -> op map. Note that I.2 R.2-2 will wipe out I.2 even though, technically, the inserted stuff would be before the replace range. But, if you add tokens in front of a method body '{' and then delete the method body, I think the stuff before the '{' you added should disappear too. Return a map from token index to operation. """ # WALK REPLACES for i, rop in enumerate(rewrites): if not rop: continue if not isinstance(rop, ReplaceOp): continue # Wipe prior inserts within range for j, iop in self.getKindOfOps(rewrites, InsertBeforeOp, i): if iop.index == rop.index: # E.g., insert before 2, delete 2..2; update replace # text to include insert before, kill insert rewrites[iop.instructionIndex] = None rop.text = self.catOpText(iop.text, rop.text) elif iop.index > rop.index and iop.index <= rop.lastIndex: # delete insert as it's a no-op. rewrites[j] = None # Drop any prior replaces contained within for j, prevRop in self.getKindOfOps(rewrites, ReplaceOp, i): if (prevRop.index >= rop.index and prevRop.lastIndex <= rop.lastIndex): # delete replace as it's a no-op. rewrites[j] = None continue # throw exception unless disjoint or identical disjoint = (prevRop.lastIndex < rop.index or prevRop.index > rop.lastIndex) same = (prevRop.index == rop.index and prevRop.lastIndex == rop.lastIndex) # Delete special case of replace (text==null): # D.i-j.u D.x-y.v| boundaries overlapcombine to # max(min)..max(right) if prevRop.text is None and rop.text is None and not disjoint: # kill first delete rewrites[prevRop.instructionIndex] = None rop.index = min(prevRop.index, rop.index) rop.lastIndex = max(prevRop.lastIndex, rop.lastIndex) elif not disjoint and not same: raise ValueError( "replace op boundaries of {} overlap with previous {}" .format(rop, prevRop)) # WALK INSERTS for i, iop in enumerate(rewrites): if iop is None: continue if not isinstance(iop, InsertBeforeOp): continue # combine current insert with prior if any at same index for j, prevIop in self.getKindOfOps(rewrites, InsertBeforeOp, i): if prevIop.index == iop.index: # combine objects # convert to strings...we're in process of toString'ing # whole token buffer so no lazy eval issue with any # templates iop.text = self.catOpText(iop.text, prevIop.text) # delete redundant prior insert rewrites[j] = None # look for replaces where iop.index is in range; error for j, rop in self.getKindOfOps(rewrites, ReplaceOp, i): if iop.index == rop.index: rop.text = self.catOpText(iop.text, rop.text) # delete current insert rewrites[i] = None continue if iop.index >= rop.index and iop.index <= rop.lastIndex: raise ValueError( "insert op {} within boundaries of previous {}" .format(iop, rop)) m = {} for i, op in enumerate(rewrites): if op is None: # ignore deleted ops continue assert op.index not in m, "should only be one op per index" m[op.index] = op return m def catOpText(self, a, b): x = "" y = "" if a: x = a if b: y = b return x + y def getKindOfOps(self, rewrites, kind, before=None): """Get all operations before an index of a particular kind.""" if before is None: before = len(rewrites) elif before > len(rewrites): before = len(rewrites) for i, op in enumerate(rewrites[:before]): # ignore deleted if op and op.__class__ == kind: yield i, op def toDebugString(self, start=None, end=None): if start is None: start = self.MIN_TOKEN_INDEX if end is None: end = self.size() - 1 buf = StringIO() i = start while i >= self.MIN_TOKEN_INDEX and i <= end and i < len(self.tokens): buf.write(self.get(i)) i += 1 return buf.getvalue()