def test_error(self): #basicConfig(level=INFO) class Term(Node): pass class Factor(Node): pass class Expression(Node): pass expression = Delayed() number = Digit()[1:, ...] > 'number' term = Or( AnyBut(Space() | Digit() | '(')[1:, ...] ^ 'unexpected text: {results[0]}', number > Term, number**make_error("no ( before '{stream_out}'") / ')' >> node_throw, '(' / expression / ')' > Term, ('(' / expression / Eos())**make_error("no ) for '{stream_in}'") >> node_throw) muldiv = Any('*/') > 'operator' factor = (term / (muldiv / term)[0:, r'\s*']) > Factor addsub = Any('+-') > 'operator' expression += (factor / (addsub / factor)[0:, r'\s*']) > Expression line = expression / Eos() parser = line.get_parse_string() try: parser('1 + 2 * 3 + 4 - 5)')[0] assert False, 'expected error' except SyntaxError as e: assert e.msg == "no ( before ')'", e.msg try: parser('1 + 2 * (3 + 4 - 5') assert False, 'expected error' except SyntaxError as e: assert e.msg == "no ) for '(3 + 4 - 5'", e.msg try: parser('1 + 2 * foo') assert False, 'expected error' except SyntaxError as e: assert e.msg == "unexpected text: foo", e.msg
def test_node(self): #basicConfig(level=DEBUG) class Term(Node): pass class Factor(Node): pass class Expression(Node): pass expression = Delayed() number = Digit()[1:, ...] > 'number' term = (number | '(' / expression / ')') > Term muldiv = Any('*/') > 'operator' factor = (term / (muldiv / term)[0::]) > Factor addsub = Any('+-') > 'operator' expression += (factor / (addsub / factor)[0::]) > Expression p = expression.get_parse_string() ast = p('1 + 2 * (3 + 4 - 5)') assert_str( ast[0], """Expression +- Factor | +- Term | | `- number '1' | `- ' ' +- operator '+' +- ' ' `- Factor +- Term | `- number '2' +- ' ' +- operator '*' +- ' ' `- Term +- '(' +- Expression | +- Factor | | +- Term | | | `- number '3' | | `- ' ' | +- operator '+' | +- ' ' | +- Factor | | +- Term | | | `- number '4' | | `- ' ' | +- operator '-' | +- ' ' | `- Factor | `- Term | `- number '5' `- ')'""")
class ExtensionParser(object): """ A class that parses extensions. """ class ExtensionCall(Node): """ An extension call. """ _name = None _args = None _kwargs = None @property def name(self): return self._name[0] if self._name else None @property def args(self): return tuple(self._args) if self._args else tuple() @property def kwargs(self): return dict(self._kwargs) if self._kwargs else {} COMMA = Drop(',') NONE = Literal('None') >> (lambda x: None) BOOL = (Literal('True') | Literal('False')) >> (lambda x: x == 'True') IDENTIFIER = Word(Letter() | '_', Letter() | '_' | Digit()) FLOAT = Real() >> float INTEGER = Integer() >> int STRING = String() | String("'") ITEM = STRING | INTEGER | FLOAT | NONE | BOOL | IDENTIFIER with Separator(~Regexp(r'\s*')): VALUE = Delayed() LIST = Drop('[') & VALUE[:, COMMA] & Drop(']') > list TUPLE = Drop('(') & VALUE[:, COMMA] & Drop(')') > tuple VALUE += LIST | TUPLE | ITEM ARGUMENT = VALUE >> '_args' KWARGUMENT = (IDENTIFIER & Drop('=') & VALUE > tuple) >> '_kwargs' ARGUMENTS = (KWARGUMENT | ARGUMENT)[:, COMMA] NAME = IDENTIFIER > '_name' EXTENSION = ((NAME & Drop('(') & ARGUMENTS & Drop(')')) | NAME) & Eos() > ExtensionCall @property def parser(self): return self.EXTENSION.get_parse_string()
def create_parser(delimiter): space = Space() comma = Drop(',') | Drop(',') + space if delimiter == ',': # by comma seperator = Separator(~Regexp(r'\s*')) delimiter = comma else: assert delimiter == ' ', 'delimiter "%s" not supported' % delimiter seperator = DroppedSpace() delimiter = space none = Literal('None') >> (lambda x: None) bool = (Literal('True') | Literal('False')) >> (lambda x: x == 'True') ident = Word(Letter() | '_', Letter() | '_' | Digit()) float_ = Float() >> float int_ = Integer() >> int str_ = String() | String("'") dict_key = str_ | int_ | float_ | Word() dict_spaces = ~Whitespace()[:] dict_value = dict_key item = str_ | int_ | float_ | none | bool | ident | Word() with seperator: value = Delayed() list_ = Drop('[') & value[:, comma] & Drop(']') > list tuple_ = Drop('(') & value[:, comma] & Drop(')') > tuple dict_el = dict_key & Drop(':') & value > tuple dict_ = Drop('{') & dict_el[1:, Drop(',')] & Drop('}') > dict value += list_ | tuple_ | dict_ | item | space arg = value >> 'arg' karg = (ident & Drop('=') & value > tuple) >> 'karg' expr = (karg | arg)[:, delimiter] & Drop(Eos()) > Node return expr.get_parse()
def test_list(self): #basicConfig(level=DEBUG) expression = Delayed() number = Digit()[1:, ...] > 'number' term = (number | '(' / expression / ')') > list muldiv = Any('*/') > 'operator' factor = (term / (muldiv / term)[0:]) > list addsub = Any('+-') > 'operator' expression += (factor / (addsub / factor)[0:]) > list ast = expression.parse_string('1 + 2 * (3 + 4 - 5)') assert ast == [[[[('number', '1')], ' '], ('operator', '+'), ' ', [[('number', '2')], ' ', ('operator', '*'), ' ', [ '(', [[[('number', '3')], ' '], ('operator', '+'), ' ', [[('number', '4')], ' '], ('operator', '-'), ' ', [[('number', '5')]]], ')' ]]]], ast
def test_transformed_etc(self): class Term(Node): pass class Factor(Node): pass class Expression(Node): pass expression = Delayed() number = Digit()[1:,...] > 'number' term = (number | '(' / expression / ')') > Term muldiv = Any('*/') > 'operator' factor = (term / (muldiv / term)[0::]) > Factor addsub = Any('+-') > 'operator' expression += (factor / (addsub / factor)[0::]) > Expression self.assert_clone(expression) self.assert_relative(expression) expression.config.no_full_first_match().no_compile_to_regexp() expression.config.no_compose_transforms().no_direct_eval() expression.config.no_flatten() copy = expression.get_parse_string().matcher self._assert_clone(expression, copy)
def make_binary_parser(): ''' Create a parser for binary data. ''' # avoid import loops from lepl import Word, Letter, Digit, UnsignedInteger, \ Regexp, DfaRegexp, Drop, Separator, Delayed, Optional, Any, First, \ args, Trace, TraceVariables from lepl.bin.bits import BitString from lepl.support.node import Node classes = {} def named_class(name, *args): ''' Given a name and some args, create a sub-class of Binary and create an instance with the given content. ''' if name not in classes: classes[name] = type(name, (Node, ), {}) return classes[name](*args) with TraceVariables(False): mult = lambda l, n: BitString.from_sequence([l] * int(n, 0)) # an attribute or class name name = Word(Letter(), Letter() | Digit() | '_') # lengths can be integers (bits) or floats (bytes.bits) # but if we have a float, we do not want to parse as an int # (or we will get a conversion error due to too small length) length = First( UnsignedInteger() + '.' + Optional(UnsignedInteger()), UnsignedInteger()) # a literal decimal decimal = UnsignedInteger() # a binary number (without pre/postfix) binary = Any('01')[1:] # an octal number (without pre/postfix) octal = Any('01234567')[1:] # a hex number (without pre/postfix) hex_ = Regexp('[a-fA-F0-9]')[1:] # the letters used for binary, octal and hex values #(eg the 'x' in 0xffee) # pylint: disable-msg=C0103 b, o, x, d = Any('bB'), Any('oO'), Any('xX'), Any('dD') # a decimal with optional pre/postfix dec = '0' + d + decimal | decimal + d + '0' | decimal # little-endian literals have normal prefix syntax (eg 0xffee) little = decimal | '0' + (b + binary | o + octal | x + hex_) # big-endian literals have postfix (eg ffeex0) big = (binary + b | octal + o | hex_ + x) + '0' # optional spaces - will be ignored # (use DFA here because it's multi-line, so \n will match ok) spaces = Drop(DfaRegexp('[ \t\n\r]*')) with Separator(spaces): # the grammar is recursive - expressions can contain expressions - # so we use a delayed matcher here as a placeholder, so that we can # use them before they are defined. expr = Delayed() # an implicit length value can be big or little-endian ivalue = big | little > args(BitString.from_int) # a value with a length can also be decimal lvalue = (big | little | dec) & Drop('/') & length \ > args(BitString.from_int) value = lvalue | ivalue repeat = value & Drop('*') & little > args(mult) # a named value is also a tuple named = name & Drop('=') & (expr | value | repeat) > tuple # an entry in the expression could be any of these entry = named | value | repeat | expr # and an expression itself consists of a comma-separated list of # one or more entries, surrounded by paremtheses entries = Drop('(') & entry[1:, Drop(',')] & Drop(')') # the Binary node may be explicit or implicit and takes the list of # entries as an argument list node = Optional(Drop('Node')) & entries > Node # alternatively, we can give a name and create a named sub-class other = name & entries > args(named_class) # and finally, we "tie the knot" by giving a definition for the # delayed matcher we introduced earlier, which is either a binary # node or a subclass expr += spaces & (node | other) & spaces #expr = Trace(expr) # this changes order, making 0800x0 parse as binary expr.config.no_compile_to_regexp() # use sequence to force regexp over multiple lines return expr.get_parse_sequence()