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()