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_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
array_type = Or(*generate_type_tokens(symboltable.array_types))
array_element_type = Or(*generate_type_tokens(symboltable.array_element_types))
type_ = scalar_type | array_type | array_element_type
real = Token(UnsignedReal()) >> Real
integer = Token(UnsignedInteger()) >> Integer
number = integer | real
boolean = keyword("yes") >> Bool | keyword("no") >> Bool | keyword("true") >> Bool | keyword("false") >> Bool
width = integer
height = integer
depth = integer
unopened_size_block = (width & Optional(~comma & height & Optional(~comma & depth)) & symbol("]")) ** make_error(
"no [ before {out_rest!s}"
) & symbol("]")
unclosed_size_block = (symbol("[") & width & Optional(~comma & height & Optional(~comma & depth))) ** make_error(
"Array size specification is missing a closing ]"
)
size = Or(
(~symbol("[") & width & Optional(~comma & height & Optional(~comma & depth)) & ~symbol("]")) ** with_line(Size),
unopened_size_block,
unclosed_size_block,
)
#### Expression Parsing ####
# Operator precedence, inside to outside
# 1 parentheses ()
# 2 not, unary minus (!, -)
def missing(label):
"""Provides feedback when a matcher fails.
This function is commonly applied using the :class:`First`
operator (short-hand: ``\%``).
We'll consider the following example phrase:
>>> example_phrase
['John' (W), 'Smith' (W), ',' (D), 16 (I), 'M' (W)]
The following matcher illustrates the usage:
>>> matcher = Word[1:] & lepl.Optional(
... Delimiter & (Number & Word) % missing('age and sex'))
Omitting the last token from our example phrase, we get the
following feedback:
>>> parse(matcher, example_phrase[:-1])[0]
u'age and sex'
To improve feedback, we can provide help for each case
individually:
>>> matcher = Word[1:] % missing('name') & lepl.Optional(
... Delimiter & Number % missing('age') & Word % missing('sex'))
The ``\%`` operator binds more strongly and parentheses are
unnecessary for the most part.
>>> parse(matcher, example_phrase[:-2])[0]
u'age'
>>> parse(matcher, example_phrase[:-1])[0]
u'sex'
Note that the full phrase still returns a match:
>>> parse(matcher, example_phrase)
['John' (W), 'Smith' (W), 16 (I), 'M' (W)]
So far we've dealt with missing input only; the function also
guards against incorrect input:
>>> phrase = example_phrase[:-2] + example_phrase[:1]
>>> parse(matcher, phrase)[0]
u'age'
Finally, the function operates within a more complex environment
of multiple paths.
>>> matcher = Word[1:] % missing('name') & \\
... lepl.Optional(
... Delimiter & Number % missing('age') & Word % missing('sex')) & \\
... lepl.Optional(
... Delimiter & Number % missing('age'))
>>> parse(matcher, example_phrase[:-2])[0]
u'age'
Omitting only the last token, this particular matcher chooses the
path through the second optional clause and succeeds:
>>> parse(matcher, example_phrase[:-1])
['John' (W), 'Smith' (W), 16 (I)]
"""
return lepl.Any()[:] ** lepl.make_error(label)
type_ = scalar_type | array_type | array_element_type
real = Token(UnsignedReal()) >> Real
integer = Token(UnsignedInteger()) >> Integer
number = integer | real
boolean = keyword('yes') >> Bool | keyword('no') >> Bool | keyword(
'true') >> Bool | keyword('false') >> Bool
width = integer
height = integer
depth = integer
unopened_size_block = (
width & Optional(~comma & height & Optional(~comma & depth))
& symbol(']'))**make_error('no [ before {out_rest!s}') & symbol(']')
unclosed_size_block = (
symbol('[') & width & Optional(~comma & height & Optional(~comma & depth))
)**make_error('Array size specification is missing a closing ]')
size = Or((~symbol('[') & width
& Optional(~comma & height
& Optional(~comma & depth))
& ~symbol(']'))**with_line(Size), unopened_size_block,
unclosed_size_block)
#### Expression Parsing ####
# Operator precedence, inside to outside
# 1 parentheses ()
# 2 not, unary minus (!, -)
# 3 multiplication, division (*, /, %)