|
# Scanner produces tokens of the following types: # STREAM-START # STREAM-END # DIRECTIVE(name, value) # DOCUMENT-START # DOCUMENT-END # BLOCK-SEQUENCE-START # BLOCK-MAPPING-START # BLOCK-END # FLOW-SEQUENCE-START # FLOW-MAPPING-START # FLOW-SEQUENCE-END # FLOW-MAPPING-END # BLOCK-ENTRY # FLOW-ENTRY # KEY # VALUE # ALIAS(value) # ANCHOR(value) # TAG(value) # SCALAR(value, plain, style) # # Read comments in the Scanner code for more details. #
# See below simple keys treatment.
self.token_number = token_number self.required = required self.index = index self.line = line self.column = column self.mark = mark
"""Initialize the scanner.""" # It is assumed that Scanner and Reader will have a common descendant. # Reader do the dirty work of checking for BOM and converting the # input data to Unicode. It also adds NUL to the end. # # Reader supports the following methods # self.peek(i=0) # peek the next i-th character # self.prefix(l=1) # peek the next l characters # self.forward(l=1) # read the next l characters and move the pointer.
# Had we reached the end of the stream? self.done = False
# The number of unclosed '{' and '['. `flow_level == 0` means block # context. self.flow_level = 0
# List of processed tokens that are not yet emitted. self.tokens = []
# Add the STREAM-START token. self.fetch_stream_start()
# Number of tokens that were emitted through the `get_token` method. self.tokens_taken = 0
# The current indentation level. self.indent = -1
# Past indentation levels. self.indents = []
# Variables related to simple keys treatment.
# A simple key is a key that is not denoted by the '?' indicator. # Example of simple keys: # --- # block simple key: value # ? not a simple key: # : { flow simple key: value } # We emit the KEY token before all keys, so when we find a potential # simple key, we try to locate the corresponding ':' indicator. # Simple keys should be limited to a single line and 1024 characters.
# Can a simple key start at the current position? A simple key may # start: # - at the beginning of the line, not counting indentation spaces # (in block context), # - after '{', '[', ',' (in the flow context), # - after '?', ':', '-' (in the block context). # In the block context, this flag also signifies if a block collection # may start at the current position. self.allow_simple_key = True
# Keep track of possible simple keys. This is a dictionary. The key # is `flow_level`; there can be no more that one possible simple key # for each level. The value is a SimpleKey record: # (token_number, required, index, line, column, mark) # A simple key may start with ALIAS, ANCHOR, TAG, SCALAR(flow), # '[', or '{' tokens. self.possible_simple_keys = {}
# Public methods.
# Check if the next token is one of the given types. while self.need_more_tokens(): self.fetch_more_tokens() if self.tokens: if not choices: return True for choice in choices: if isinstance(self.tokens[0], choice): return True return False
# Return the next token, but do not delete if from the queue. while self.need_more_tokens(): self.fetch_more_tokens() if self.tokens: return self.tokens[0]
# Return the next token. while self.need_more_tokens(): self.fetch_more_tokens() if self.tokens: self.tokens_taken += 1 return self.tokens.pop(0)
# Private methods.
if self.done: return False if not self.tokens: return True # The current token may be a potential simple key, so we # need to look further. self.stale_possible_simple_keys() if self.next_possible_simple_key() == self.tokens_taken: return True
# Eat whitespaces and comments until we reach the next token. self.scan_to_next_token()
# Remove obsolete possible simple keys. self.stale_possible_simple_keys()
# Compare the current indentation and column. It may add some tokens # and decrease the current indentation level. self.unwind_indent(self.column)
# Peek the next character. ch = self.peek()
# Is it the end of stream? if ch == '\0': return self.fetch_stream_end()
# Is it a directive? if ch == '%' and self.check_directive(): return self.fetch_directive()
# Is it the document start? if ch == '-' and self.check_document_start(): return self.fetch_document_start()
# Is it the document end? if ch == '.' and self.check_document_end(): return self.fetch_document_end()
# TODO: support for BOM within a stream. #if ch == '\uFEFF': # return self.fetch_bom() <-- issue BOMToken
# Note: the order of the following checks is NOT significant.
# Is it the flow sequence start indicator? if ch == '[': return self.fetch_flow_sequence_start()
# Is it the flow mapping start indicator? if ch == '{': return self.fetch_flow_mapping_start()
# Is it the flow sequence end indicator? if ch == ']': return self.fetch_flow_sequence_end()
# Is it the flow mapping end indicator? if ch == '}': return self.fetch_flow_mapping_end()
# Is it the flow entry indicator? if ch == ',': return self.fetch_flow_entry()
# Is it the block entry indicator? if ch == '-' and self.check_block_entry(): return self.fetch_block_entry()
# Is it the key indicator? if ch == '?' and self.check_key(): return self.fetch_key()
# Is it the value indicator? if ch == ':' and self.check_value(): return self.fetch_value()
# Is it an alias? if ch == '*': return self.fetch_alias()
# Is it an anchor? if ch == '&': return self.fetch_anchor()
# Is it a tag? if ch == '!': return self.fetch_tag()
# Is it a literal scalar? if ch == '|' and not self.flow_level: return self.fetch_literal()
# Is it a folded scalar? if ch == '>' and not self.flow_level: return self.fetch_folded()
# Is it a single quoted scalar? if ch == '\'': return self.fetch_single()
# Is it a double quoted scalar? if ch == '\"': return self.fetch_double()
# It must be a plain scalar then. if self.check_plain(): return self.fetch_plain()
# No? It's an error. Let's produce a nice error message. raise ScannerError("while scanning for the next token", None, "found character %r that cannot start any token" % ch, self.get_mark())
# Simple keys treatment.
# Return the number of the nearest possible simple key. Actually we # don't need to loop through the whole dictionary. We may replace it # with the following code: # if not self.possible_simple_keys: # return None # return self.possible_simple_keys[ # min(self.possible_simple_keys.keys())].token_number min_token_number = None for level in self.possible_simple_keys: key = self.possible_simple_keys[level] if min_token_number is None or key.token_number < min_token_number: min_token_number = key.token_number return min_token_number
# Remove entries that are no longer possible simple keys. According to # the YAML specification, simple keys # - should be limited to a single line, # - should be no longer than 1024 characters. # Disabling this procedure will allow simple keys of any length and # height (may cause problems if indentation is broken though). for level in list(self.possible_simple_keys): key = self.possible_simple_keys[level] if key.line != self.line \ or self.index-key.index > 1024: if key.required: raise ScannerError("while scanning a simple key", key.mark, "could not find expected ':'", self.get_mark()) del self.possible_simple_keys[level]
# The next token may start a simple key. We check if it's possible # and save its position. This function is called for # ALIAS, ANCHOR, TAG, SCALAR(flow), '[', and '{'.
# Check if a simple key is required at the current position. required = not self.flow_level and self.indent == self.column
# The next token might be a simple key. Let's save it's number and # position. if self.allow_simple_key: self.remove_possible_simple_key() token_number = self.tokens_taken+len(self.tokens) key = SimpleKey(token_number, required, self.index, self.line, self.column, self.get_mark()) self.possible_simple_keys[self.flow_level] = key
# Remove the saved possible key position at the current flow level. if self.flow_level in self.possible_simple_keys: key = self.possible_simple_keys[self.flow_level]
if key.required: raise ScannerError("while scanning a simple key", key.mark, "could not find expected ':'", self.get_mark())
del self.possible_simple_keys[self.flow_level]
# Indentation functions.
## In flow context, tokens should respect indentation. ## Actually the condition should be `self.indent >= column` according to ## the spec. But this condition will prohibit intuitively correct ## constructions such as ## key : { ## } #if self.flow_level and self.indent > column: # raise ScannerError(None, None, # "invalid intendation or unclosed '[' or '{'", # self.get_mark())
# In the flow context, indentation is ignored. We make the scanner less # restrictive then specification requires. if self.flow_level: return
# In block context, we may need to issue the BLOCK-END tokens. while self.indent > column: mark = self.get_mark() self.indent = self.indents.pop() self.tokens.append(BlockEndToken(mark, mark))
# Check if we need to increase indentation. if self.indent < column: self.indents.append(self.indent) self.indent = column return True return False
# Fetchers.
# We always add STREAM-START as the first token and STREAM-END as the # last token.
# Read the token. mark = self.get_mark()
# Add STREAM-START. self.tokens.append(StreamStartToken(mark, mark, encoding=self.encoding))
# Set the current intendation to -1. self.unwind_indent(-1)
# Reset simple keys. self.remove_possible_simple_key() self.allow_simple_key = False self.possible_simple_keys = {}
# Read the token. mark = self.get_mark()
# Add STREAM-END. self.tokens.append(StreamEndToken(mark, mark))
# The steam is finished. self.done = True
# Set the current intendation to -1. self.unwind_indent(-1)
# Reset simple keys. self.remove_possible_simple_key() self.allow_simple_key = False
# Scan and add DIRECTIVE. self.tokens.append(self.scan_directive())
self.fetch_document_indicator(DocumentStartToken)
self.fetch_document_indicator(DocumentEndToken)
# Set the current intendation to -1. self.unwind_indent(-1)
# Reset simple keys. Note that there could not be a block collection # after '---'. self.remove_possible_simple_key() self.allow_simple_key = False
# Add DOCUMENT-START or DOCUMENT-END. start_mark = self.get_mark() self.forward(3) end_mark = self.get_mark() self.tokens.append(TokenClass(start_mark, end_mark))
self.fetch_flow_collection_start(FlowSequenceStartToken)
self.fetch_flow_collection_start(FlowMappingStartToken)
# '[' and '{' may start a simple key. self.save_possible_simple_key()
# Increase the flow level. self.flow_level += 1
# Simple keys are allowed after '[' and '{'. self.allow_simple_key = True
# Add FLOW-SEQUENCE-START or FLOW-MAPPING-START. start_mark = self.get_mark() self.forward() end_mark = self.get_mark() self.tokens.append(TokenClass(start_mark, end_mark))
self.fetch_flow_collection_end(FlowSequenceEndToken)
self.fetch_flow_collection_end(FlowMappingEndToken)
# Reset possible simple key on the current level. self.remove_possible_simple_key()
# Decrease the flow level. self.flow_level -= 1
# No simple keys after ']' or '}'. self.allow_simple_key = False
# Add FLOW-SEQUENCE-END or FLOW-MAPPING-END. start_mark = self.get_mark() self.forward() end_mark = self.get_mark() self.tokens.append(TokenClass(start_mark, end_mark))
# Simple keys are allowed after ','. self.allow_simple_key = True
# Reset possible simple key on the current level. self.remove_possible_simple_key()
# Add FLOW-ENTRY. start_mark = self.get_mark() self.forward() end_mark = self.get_mark() self.tokens.append(FlowEntryToken(start_mark, end_mark))
# Block context needs additional checks. if not self.flow_level:
# Are we allowed to start a new entry? if not self.allow_simple_key: raise ScannerError(None, None, "sequence entries are not allowed here", self.get_mark())
# We may need to add BLOCK-SEQUENCE-START. if self.add_indent(self.column): mark = self.get_mark() self.tokens.append(BlockSequenceStartToken(mark, mark))
# It's an error for the block entry to occur in the flow context, # but we let the parser detect this. else: pass
# Simple keys are allowed after '-'. self.allow_simple_key = True
# Reset possible simple key on the current level. self.remove_possible_simple_key()
# Add BLOCK-ENTRY. start_mark = self.get_mark() self.forward() end_mark = self.get_mark() self.tokens.append(BlockEntryToken(start_mark, end_mark))
# Block context needs additional checks. if not self.flow_level:
# Are we allowed to start a key (not nessesary a simple)? if not self.allow_simple_key: raise ScannerError(None, None, "mapping keys are not allowed here", self.get_mark())
# We may need to add BLOCK-MAPPING-START. if self.add_indent(self.column): mark = self.get_mark() self.tokens.append(BlockMappingStartToken(mark, mark))
# Simple keys are allowed after '?' in the block context. self.allow_simple_key = not self.flow_level
# Reset possible simple key on the current level. self.remove_possible_simple_key()
# Add KEY. start_mark = self.get_mark() self.forward() end_mark = self.get_mark() self.tokens.append(KeyToken(start_mark, end_mark))
# Do we determine a simple key? if self.flow_level in self.possible_simple_keys:
# Add KEY. key = self.possible_simple_keys[self.flow_level] del self.possible_simple_keys[self.flow_level] self.tokens.insert(key.token_number-self.tokens_taken, KeyToken(key.mark, key.mark))
# If this key starts a new block mapping, we need to add # BLOCK-MAPPING-START. if not self.flow_level: if self.add_indent(key.column): self.tokens.insert(key.token_number-self.tokens_taken, BlockMappingStartToken(key.mark, key.mark))
# There cannot be two simple keys one after another. self.allow_simple_key = False
# It must be a part of a complex key. else:
# Block context needs additional checks. # (Do we really need them? They will be catched by the parser # anyway.) if not self.flow_level:
# We are allowed to start a complex value if and only if # we can start a simple key. if not self.allow_simple_key: raise ScannerError(None, None, "mapping values are not allowed here", self.get_mark())
# If this value starts a new block mapping, we need to add # BLOCK-MAPPING-START. It will be detected as an error later by # the parser. if not self.flow_level: if self.add_indent(self.column): mark = self.get_mark() self.tokens.append(BlockMappingStartToken(mark, mark))
# Simple keys are allowed after ':' in the block context. self.allow_simple_key = not self.flow_level
# Reset possible simple key on the current level. self.remove_possible_simple_key()
# Add VALUE. start_mark = self.get_mark() self.forward() end_mark = self.get_mark() self.tokens.append(ValueToken(start_mark, end_mark))
# ALIAS could be a simple key. self.save_possible_simple_key()
# No simple keys after ALIAS. self.allow_simple_key = False
# Scan and add ALIAS. self.tokens.append(self.scan_anchor(AliasToken))
# ANCHOR could start a simple key. self.save_possible_simple_key()
# No simple keys after ANCHOR. self.allow_simple_key = False
# Scan and add ANCHOR. self.tokens.append(self.scan_anchor(AnchorToken))
# TAG could start a simple key. self.save_possible_simple_key()
# No simple keys after TAG. self.allow_simple_key = False
# Scan and add TAG. self.tokens.append(self.scan_tag())
self.fetch_block_scalar(style='|')
self.fetch_block_scalar(style='>')
# A simple key may follow a block scalar. self.allow_simple_key = True
# Reset possible simple key on the current level. self.remove_possible_simple_key()
# Scan and add SCALAR. self.tokens.append(self.scan_block_scalar(style))
self.fetch_flow_scalar(style='\'')
self.fetch_flow_scalar(style='"')
# A flow scalar could be a simple key. self.save_possible_simple_key()
# No simple keys after flow scalars. self.allow_simple_key = False
# Scan and add SCALAR. self.tokens.append(self.scan_flow_scalar(style))
# A plain scalar could be a simple key. self.save_possible_simple_key()
# No simple keys after plain scalars. But note that `scan_plain` will # change this flag if the scan is finished at the beginning of the # line. self.allow_simple_key = False
# Scan and add SCALAR. May change `allow_simple_key`. self.tokens.append(self.scan_plain())
# Checkers.
# DIRECTIVE: ^ '%' ... # The '%' indicator is already checked. if self.column == 0: return True
# DOCUMENT-START: ^ '---' (' '|'\n') if self.column == 0: if self.prefix(3) == '---' \ and self.peek(3) in '\0 \t\r\n\x85\u2028\u2029': return True
# DOCUMENT-END: ^ '...' (' '|'\n') if self.column == 0: if self.prefix(3) == '...' \ and self.peek(3) in '\0 \t\r\n\x85\u2028\u2029': return True
# BLOCK-ENTRY: '-' (' '|'\n') return self.peek(1) in '\0 \t\r\n\x85\u2028\u2029'
# KEY(flow context): '?' if self.flow_level: return True
# KEY(block context): '?' (' '|'\n') else: return self.peek(1) in '\0 \t\r\n\x85\u2028\u2029'
# VALUE(flow context): ':' if self.flow_level: return True
# VALUE(block context): ':' (' '|'\n') else: return self.peek(1) in '\0 \t\r\n\x85\u2028\u2029'
# A plain scalar may start with any non-space character except: # '-', '?', ':', ',', '[', ']', '{', '}', # '#', '&', '*', '!', '|', '>', '\'', '\"', # '%', '@', '`'. # # It may also start with # '-', '?', ':' # if it is followed by a non-space character. # # Note that we limit the last rule to the block context (except the # '-' character) because we want the flow context to be space # independent. ch = self.peek() return ch not in '\0 \t\r\n\x85\u2028\u2029-?:,[]{}#&*!|>\'\"%@`' \ or (self.peek(1) not in '\0 \t\r\n\x85\u2028\u2029' and (ch == '-' or (not self.flow_level and ch in '?:')))
# Scanners.
# We ignore spaces, line breaks and comments. # If we find a line break in the block context, we set the flag # `allow_simple_key` on. # The byte order mark is stripped if it's the first character in the # stream. We do not yet support BOM inside the stream as the # specification requires. Any such mark will be considered as a part # of the document. # # TODO: We need to make tab handling rules more sane. A good rule is # Tabs cannot precede tokens # BLOCK-SEQUENCE-START, BLOCK-MAPPING-START, BLOCK-END, # KEY(block), VALUE(block), BLOCK-ENTRY # So the checking code is # if <TAB>: # self.allow_simple_keys = False # We also need to add the check for `allow_simple_keys == True` to # `unwind_indent` before issuing BLOCK-END. # Scanners for block, flow, and plain scalars need to be modified.
if self.index == 0 and self.peek() == '\uFEFF': self.forward() found = False while not found: while self.peek() == ' ': self.forward() if self.peek() == '#': while self.peek() not in '\0\r\n\x85\u2028\u2029': self.forward() if self.scan_line_break(): if not self.flow_level: self.allow_simple_key = True else: found = True
# See the specification for details. start_mark = self.get_mark() self.forward() name = self.scan_directive_name(start_mark) value = None if name == 'YAML': value = self.scan_yaml_directive_value(start_mark) end_mark = self.get_mark() elif name == 'TAG': value = self.scan_tag_directive_value(start_mark) end_mark = self.get_mark() else: end_mark = self.get_mark() while self.peek() not in '\0\r\n\x85\u2028\u2029': self.forward() self.scan_directive_ignored_line(start_mark) return DirectiveToken(name, value, start_mark, end_mark)
# See the specification for details. length = 0 ch = self.peek(length) while '0' <= ch <= '9' or 'A' <= ch <= 'Z' or 'a' <= ch <= 'z' \ or ch in '-_': length += 1 ch = self.peek(length) if not length: raise ScannerError("while scanning a directive", start_mark, "expected alphabetic or numeric character, but found %r" % ch, self.get_mark()) value = self.prefix(length) self.forward(length) ch = self.peek() if ch not in '\0 \r\n\x85\u2028\u2029': raise ScannerError("while scanning a directive", start_mark, "expected alphabetic or numeric character, but found %r" % ch, self.get_mark()) return value
# See the specification for details. while self.peek() == ' ': self.forward() major = self.scan_yaml_directive_number(start_mark) if self.peek() != '.': raise ScannerError("while scanning a directive", start_mark, "expected a digit or '.', but found %r" % self.peek(), self.get_mark()) self.forward() minor = self.scan_yaml_directive_number(start_mark) if self.peek() not in '\0 \r\n\x85\u2028\u2029': raise ScannerError("while scanning a directive", start_mark, "expected a digit or ' ', but found %r" % self.peek(), self.get_mark()) return (major, minor)
# See the specification for details. ch = self.peek() if not ('0' <= ch <= '9'): raise ScannerError("while scanning a directive", start_mark, "expected a digit, but found %r" % ch, self.get_mark()) length = 0 while '0' <= self.peek(length) <= '9': length += 1 value = int(self.prefix(length)) self.forward(length) return value
# See the specification for details. while self.peek() == ' ': self.forward() handle = self.scan_tag_directive_handle(start_mark) while self.peek() == ' ': self.forward() prefix = self.scan_tag_directive_prefix(start_mark) return (handle, prefix)
# See the specification for details. value = self.scan_tag_handle('directive', start_mark) ch = self.peek() if ch != ' ': raise ScannerError("while scanning a directive", start_mark, "expected ' ', but found %r" % ch, self.get_mark()) return value
# See the specification for details. value = self.scan_tag_uri('directive', start_mark) ch = self.peek() if ch not in '\0 \r\n\x85\u2028\u2029': raise ScannerError("while scanning a directive", start_mark, "expected ' ', but found %r" % ch, self.get_mark()) return value
# See the specification for details. while self.peek() == ' ': self.forward() if self.peek() == '#': while self.peek() not in '\0\r\n\x85\u2028\u2029': self.forward() ch = self.peek() if ch not in '\0\r\n\x85\u2028\u2029': raise ScannerError("while scanning a directive", start_mark, "expected a comment or a line break, but found %r" % ch, self.get_mark()) self.scan_line_break()
# The specification does not restrict characters for anchors and # aliases. This may lead to problems, for instance, the document: # [ *alias, value ] # can be interpteted in two ways, as # [ "value" ] # and # [ *alias , "value" ] # Therefore we restrict aliases to numbers and ASCII letters. start_mark = self.get_mark() indicator = self.peek() if indicator == '*': name = 'alias' else: name = 'anchor' self.forward() length = 0 ch = self.peek(length) while '0' <= ch <= '9' or 'A' <= ch <= 'Z' or 'a' <= ch <= 'z' \ or ch in '-_': length += 1 ch = self.peek(length) if not length: raise ScannerError("while scanning an %s" % name, start_mark, "expected alphabetic or numeric character, but found %r" % ch, self.get_mark()) value = self.prefix(length) self.forward(length) ch = self.peek() if ch not in '\0 \t\r\n\x85\u2028\u2029?:,]}%@`': raise ScannerError("while scanning an %s" % name, start_mark, "expected alphabetic or numeric character, but found %r" % ch, self.get_mark()) end_mark = self.get_mark() return TokenClass(value, start_mark, end_mark)
# See the specification for details. start_mark = self.get_mark() ch = self.peek(1) if ch == '<': handle = None self.forward(2) suffix = self.scan_tag_uri('tag', start_mark) if self.peek() != '>': raise ScannerError("while parsing a tag", start_mark, "expected '>', but found %r" % self.peek(), self.get_mark()) self.forward() elif ch in '\0 \t\r\n\x85\u2028\u2029': handle = None suffix = '!' self.forward() else: length = 1 use_handle = False while ch not in '\0 \r\n\x85\u2028\u2029': if ch == '!': use_handle = True break length += 1 ch = self.peek(length) handle = '!' if use_handle: handle = self.scan_tag_handle('tag', start_mark) else: handle = '!' self.forward() suffix = self.scan_tag_uri('tag', start_mark) ch = self.peek() if ch not in '\0 \r\n\x85\u2028\u2029': raise ScannerError("while scanning a tag", start_mark, "expected ' ', but found %r" % ch, self.get_mark()) value = (handle, suffix) end_mark = self.get_mark() return TagToken(value, start_mark, end_mark)
# See the specification for details.
if style == '>': folded = True else: folded = False
chunks = [] start_mark = self.get_mark()
# Scan the header. self.forward() chomping, increment = self.scan_block_scalar_indicators(start_mark) self.scan_block_scalar_ignored_line(start_mark)
# Determine the indentation level and go to the first non-empty line. min_indent = self.indent+1 if min_indent < 1: min_indent = 1 if increment is None: breaks, max_indent, end_mark = self.scan_block_scalar_indentation() indent = max(min_indent, max_indent) else: indent = min_indent+increment-1 breaks, end_mark = self.scan_block_scalar_breaks(indent) line_break = ''
# Scan the inner part of the block scalar. while self.column == indent and self.peek() != '\0': chunks.extend(breaks) leading_non_space = self.peek() not in ' \t' length = 0 while self.peek(length) not in '\0\r\n\x85\u2028\u2029': length += 1 chunks.append(self.prefix(length)) self.forward(length) line_break = self.scan_line_break() breaks, end_mark = self.scan_block_scalar_breaks(indent) if self.column == indent and self.peek() != '\0':
# Unfortunately, folding rules are ambiguous. # # This is the folding according to the specification:
if folded and line_break == '\n' \ and leading_non_space and self.peek() not in ' \t': if not breaks: chunks.append(' ') else: chunks.append(line_break)
# This is Clark Evans's interpretation (also in the spec # examples): # #if folded and line_break == '\n': # if not breaks: # if self.peek() not in ' \t': # chunks.append(' ') # else: # chunks.append(line_break) #else: # chunks.append(line_break) else: break
# Chomp the tail. if chomping is not False: chunks.append(line_break) if chomping is True: chunks.extend(breaks)
# We are done. return ScalarToken(''.join(chunks), False, start_mark, end_mark, style)
# See the specification for details. chomping = None increment = None ch = self.peek() if ch in '+-': if ch == '+': chomping = True else: chomping = False self.forward() ch = self.peek() if ch in '0123456789': increment = int(ch) if increment == 0: raise ScannerError("while scanning a block scalar", start_mark, "expected indentation indicator in the range 1-9, but found 0", self.get_mark()) self.forward() elif ch in '0123456789': increment = int(ch) if increment == 0: raise ScannerError("while scanning a block scalar", start_mark, "expected indentation indicator in the range 1-9, but found 0", self.get_mark()) self.forward() ch = self.peek() if ch in '+-': if ch == '+': chomping = True else: chomping = False self.forward() ch = self.peek() if ch not in '\0 \r\n\x85\u2028\u2029': raise ScannerError("while scanning a block scalar", start_mark, "expected chomping or indentation indicators, but found %r" % ch, self.get_mark()) return chomping, increment
# See the specification for details. while self.peek() == ' ': self.forward() if self.peek() == '#': while self.peek() not in '\0\r\n\x85\u2028\u2029': self.forward() ch = self.peek() if ch not in '\0\r\n\x85\u2028\u2029': raise ScannerError("while scanning a block scalar", start_mark, "expected a comment or a line break, but found %r" % ch, self.get_mark()) self.scan_line_break()
# See the specification for details. chunks = [] max_indent = 0 end_mark = self.get_mark() while self.peek() in ' \r\n\x85\u2028\u2029': if self.peek() != ' ': chunks.append(self.scan_line_break()) end_mark = self.get_mark() else: self.forward() if self.column > max_indent: max_indent = self.column return chunks, max_indent, end_mark
# See the specification for details. chunks = [] end_mark = self.get_mark() while self.column < indent and self.peek() == ' ': self.forward() while self.peek() in '\r\n\x85\u2028\u2029': chunks.append(self.scan_line_break()) end_mark = self.get_mark() while self.column < indent and self.peek() == ' ': self.forward() return chunks, end_mark
# See the specification for details. # Note that we loose indentation rules for quoted scalars. Quoted # scalars don't need to adhere indentation because " and ' clearly # mark the beginning and the end of them. Therefore we are less # restrictive then the specification requires. We only need to check # that document separators are not included in scalars. if style == '"': double = True else: double = False chunks = [] start_mark = self.get_mark() quote = self.peek() self.forward() chunks.extend(self.scan_flow_scalar_non_spaces(double, start_mark)) while self.peek() != quote: chunks.extend(self.scan_flow_scalar_spaces(double, start_mark)) chunks.extend(self.scan_flow_scalar_non_spaces(double, start_mark)) self.forward() end_mark = self.get_mark() return ScalarToken(''.join(chunks), False, start_mark, end_mark, style)
'0': '\0', 'a': '\x07', 'b': '\x08', 't': '\x09', '\t': '\x09', 'n': '\x0A', 'v': '\x0B', 'f': '\x0C', 'r': '\x0D', 'e': '\x1B', ' ': '\x20', '\"': '\"', '\\': '\\', 'N': '\x85', '_': '\xA0', 'L': '\u2028', 'P': '\u2029', }
'x': 2, 'u': 4, 'U': 8, }
# See the specification for details. chunks = [] while True: length = 0 while self.peek(length) not in '\'\"\\\0 \t\r\n\x85\u2028\u2029': length += 1 if length: chunks.append(self.prefix(length)) self.forward(length) ch = self.peek() if not double and ch == '\'' and self.peek(1) == '\'': chunks.append('\'') self.forward(2) elif (double and ch == '\'') or (not double and ch in '\"\\'): chunks.append(ch) self.forward() elif double and ch == '\\': self.forward() ch = self.peek() if ch in self.ESCAPE_REPLACEMENTS: chunks.append(self.ESCAPE_REPLACEMENTS[ch]) self.forward() elif ch in self.ESCAPE_CODES: length = self.ESCAPE_CODES[ch] self.forward() for k in range(length): if self.peek(k) not in '0123456789ABCDEFabcdef': raise ScannerError("while scanning a double-quoted scalar", start_mark, "expected escape sequence of %d hexdecimal numbers, but found %r" % (length, self.peek(k)), self.get_mark()) code = int(self.prefix(length), 16) chunks.append(chr(code)) self.forward(length) elif ch in '\r\n\x85\u2028\u2029': self.scan_line_break() chunks.extend(self.scan_flow_scalar_breaks(double, start_mark)) else: raise ScannerError("while scanning a double-quoted scalar", start_mark, "found unknown escape character %r" % ch, self.get_mark()) else: return chunks
# See the specification for details. chunks = [] length = 0 while self.peek(length) in ' \t': length += 1 whitespaces = self.prefix(length) self.forward(length) ch = self.peek() if ch == '\0': raise ScannerError("while scanning a quoted scalar", start_mark, "found unexpected end of stream", self.get_mark()) elif ch in '\r\n\x85\u2028\u2029': line_break = self.scan_line_break() breaks = self.scan_flow_scalar_breaks(double, start_mark) if line_break != '\n': chunks.append(line_break) elif not breaks: chunks.append(' ') chunks.extend(breaks) else: chunks.append(whitespaces) return chunks
# See the specification for details. chunks = [] while True: # Instead of checking indentation, we check for document # separators. prefix = self.prefix(3) if (prefix == '---' or prefix == '...') \ and self.peek(3) in '\0 \t\r\n\x85\u2028\u2029': raise ScannerError("while scanning a quoted scalar", start_mark, "found unexpected document separator", self.get_mark()) while self.peek() in ' \t': self.forward() if self.peek() in '\r\n\x85\u2028\u2029': chunks.append(self.scan_line_break()) else: return chunks
# See the specification for details. # We add an additional restriction for the flow context: # plain scalars in the flow context cannot contain ',', ':' and '?'. # We also keep track of the `allow_simple_key` flag here. # Indentation rules are loosed for the flow context. chunks = [] start_mark = self.get_mark() end_mark = start_mark indent = self.indent+1 # We allow zero indentation for scalars, but then we need to check for # document separators at the beginning of the line. #if indent == 0: # indent = 1 spaces = [] while True: length = 0 if self.peek() == '#': break while True: ch = self.peek(length) if ch in '\0 \t\r\n\x85\u2028\u2029' \ or (not self.flow_level and ch == ':' and self.peek(length+1) in '\0 \t\r\n\x85\u2028\u2029') \ or (self.flow_level and ch in ',:?[]{}'): break length += 1 # It's not clear what we should do with ':' in the flow context. if (self.flow_level and ch == ':' and self.peek(length+1) not in '\0 \t\r\n\x85\u2028\u2029,[]{}'): self.forward(length) raise ScannerError("while scanning a plain scalar", start_mark, "found unexpected ':'", self.get_mark(), "Please check http://pyyaml.org/wiki/YAMLColonInFlowContext for details.") if length == 0: break self.allow_simple_key = False chunks.extend(spaces) chunks.append(self.prefix(length)) self.forward(length) end_mark = self.get_mark() spaces = self.scan_plain_spaces(indent, start_mark) if not spaces or self.peek() == '#' \ or (not self.flow_level and self.column < indent): break return ScalarToken(''.join(chunks), True, start_mark, end_mark)
# See the specification for details. # The specification is really confusing about tabs in plain scalars. # We just forbid them completely. Do not use tabs in YAML! chunks = [] length = 0 while self.peek(length) in ' ': length += 1 whitespaces = self.prefix(length) self.forward(length) ch = self.peek() if ch in '\r\n\x85\u2028\u2029': line_break = self.scan_line_break() self.allow_simple_key = True prefix = self.prefix(3) if (prefix == '---' or prefix == '...') \ and self.peek(3) in '\0 \t\r\n\x85\u2028\u2029': return breaks = [] while self.peek() in ' \r\n\x85\u2028\u2029': if self.peek() == ' ': self.forward() else: breaks.append(self.scan_line_break()) prefix = self.prefix(3) if (prefix == '---' or prefix == '...') \ and self.peek(3) in '\0 \t\r\n\x85\u2028\u2029': return if line_break != '\n': chunks.append(line_break) elif not breaks: chunks.append(' ') chunks.extend(breaks) elif whitespaces: chunks.append(whitespaces) return chunks
# See the specification for details. # For some strange reasons, the specification does not allow '_' in # tag handles. I have allowed it anyway. ch = self.peek() if ch != '!': raise ScannerError("while scanning a %s" % name, start_mark, "expected '!', but found %r" % ch, self.get_mark()) length = 1 ch = self.peek(length) if ch != ' ': while '0' <= ch <= '9' or 'A' <= ch <= 'Z' or 'a' <= ch <= 'z' \ or ch in '-_': length += 1 ch = self.peek(length) if ch != '!': self.forward(length) raise ScannerError("while scanning a %s" % name, start_mark, "expected '!', but found %r" % ch, self.get_mark()) length += 1 value = self.prefix(length) self.forward(length) return value
# See the specification for details. # Note: we do not check if URI is well-formed. chunks = [] length = 0 ch = self.peek(length) while '0' <= ch <= '9' or 'A' <= ch <= 'Z' or 'a' <= ch <= 'z' \ or ch in '-;/?:@&=+$,_.!~*\'()[]%': if ch == '%': chunks.append(self.prefix(length)) self.forward(length) length = 0 chunks.append(self.scan_uri_escapes(name, start_mark)) else: length += 1 ch = self.peek(length) if length: chunks.append(self.prefix(length)) self.forward(length) length = 0 if not chunks: raise ScannerError("while parsing a %s" % name, start_mark, "expected URI, but found %r" % ch, self.get_mark()) return ''.join(chunks)
# See the specification for details. codes = [] mark = self.get_mark() while self.peek() == '%': self.forward() for k in range(2): if self.peek(k) not in '0123456789ABCDEFabcdef': raise ScannerError("while scanning a %s" % name, start_mark, "expected URI escape sequence of 2 hexdecimal numbers, but found %r" % self.peek(k), self.get_mark()) codes.append(int(self.prefix(2), 16)) self.forward(2) try: value = bytes(codes).decode('utf-8') except UnicodeDecodeError as exc: raise ScannerError("while scanning a %s" % name, start_mark, str(exc), mark) return value
# Transforms: # '\r\n' : '\n' # '\r' : '\n' # '\n' : '\n' # '\x85' : '\n' # '\u2028' : '\u2028' # '\u2029 : '\u2029' # default : '' ch = self.peek() if ch in '\r\n\x85': if self.prefix(2) == '\r\n': self.forward(2) else: self.forward() return '\n' elif ch in '\u2028\u2029': self.forward() return ch return ''
#try: # import psyco # psyco.bind(Scanner) #except ImportError: # pass
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