def project(stream, proj):
if not isinstance(stream, Stream):
raise FlareSyntaxError(
"returning dict top-level keys must be streams.")
if proj is True:
return {'stream': stream(), 'projection': "default"}
elif proj is False:
return {'stream': stream(), 'projection': {}}
else:
nd = {}
l = [(proj, nd)]
while l:
old, new = l.pop(0)
for key, val in old.items():
if isinstance(val, EventPath):
z = val()
new[key] = [{'var': z['path'][1:]}]
elif isinstance(val, float):
new[key] = [{'lit': {'val': val, 'type': 'double'}}]
elif isinstance(val, int):
new[key] = [{'lit': {'val': val, 'type': 'int'}}]
elif isinstance(val, str):
new[key] = [{'lit': {'val': val, 'type': 'string'}}]
elif isinstance(val, bool):
new[key] = [{'lit': {'val': val, 'type': 'bool'}}]
elif isinstance(val, dict):
new[key] = {}
l.append((val, new[key]))
else:
raise FlareSyntaxError("%s: %s is unsupported." %
(key, val.__class__))
return {'stream': stream(), 'projection': nd}
def __init__(self, *q, **kwargs):
"""Initialize the switch.
TODO: Define q and kwargs
"""
for c in q:
if isinstance(c, Cond):
if not isinstance(c.path, EventPath):
raise FlareSyntaxError('Use V. for paths within event()')
else:
raise FlareSyntaxError('Use V. for paths within event()')
self._query = (tuple(q), )
self._stream = None
def __call__(self):
if self.proj is True:
return {'stream': self.stream(), 'projection': "default"}
elif self.proj is False:
return {'stream': self.stream(), 'projection': False}
else:
nd = {}
l = [(self.proj, nd)]
while l:
old, new = l.pop(0)
for key, val in old.items():
if isinstance(val, EventPath):
z = val()
new[key] = [{'var': z['path']}]
elif isinstance(val, ProjMath):
new[key] = [val()]
elif isinstance(val, float):
new[key] = [{'lit': {'val': val, 'type': 'double'}}]
elif isinstance(val, int):
new[key] = [{'lit': {'val': val, 'type': 'int'}}]
elif isinstance(val, str):
new[key] = [{'lit': {'val': val, 'type': 'string'}}]
elif isinstance(val, bool):
new[key] = [{'lit': {'val': val, 'type': 'bool'}}]
elif isinstance(val, dict):
new[key] = {}
l.append((val, new[key]))
else:
raise FlareSyntaxError("%s: %s is unsupported." %
(key, val.__class__))
return {'stream': self.stream(), 'projection': nd}
def __call__(self):
"""Generate AST code from the switch."""
if len(self._query) <= 1:
raise FlareSyntaxError(
"Switches must contain at least two `event()`'s")
else:
cds = []
for s in self._query:
if len(s) > 1:
cds.append({'type': '&&', 'args': [x() for x in s]})
elif len(s) == 1:
cds.append(s[0]())
else:
raise FlareSyntaxError(
"Switches must have non-empty conditions")
return {'type': 'switch', 'conds': cds, 'stream': self._stream()}
def __str__(self):
"""Generate a string representation of the switch."""
if len(self._query) < 2:
raise FlareSyntaxError("Switches must have two conditions")
else:
d = " -> ".join(" && ".join(
[str(x) if PY3 else str(x).decode('utf-8') for x in q])
for q in self._query) # NOQA
if self._stream:
return "{}:({})".format(str(self._stream), d)
else:
return "(" + d + ")"
def convert(p):
if isinstance(p, float):
return {'lit': {'val': p, 'type': 'double'}}
elif isinstance(p, int):
return {'lit': {'val': p, 'type': 'int'}}
elif isinstance(p, EventPath):
return {'var': p()['path']}
elif isinstance(p, ProjMath):
return p()
else:
raise FlareSyntaxError(
"projection math with non-numeric types is unsupported.")
return {'stream': self.stream(), 'projection': nd}
def __call__(self):
"""Generate an Abstract Syntax Tree for a given query"""
q, r = None, None
for s in self.statements:
if isinstance(s, Select):
if q is None:
q = s()
else:
raise FlareSyntaxError(
"Only one `select` statement may be present in a query"
)
elif isinstance(s, Span):
if q is None:
z = Select()
z._query = [s]
q = z()
else:
raise FlareSyntaxError(
"Only one `select` statement may be present in a query"
)
elif isinstance(s, Returning):
if r is None:
r = s()
else:
raise FlareSyntaxError(
"Only one `returning` statement may be present in a query"
)
else:
raise FlareSyntaxError(
"Statement must be either `returning` or `select`")
if q is None:
q = Select()()
if r is None:
r = {}
q.update(r)
return q
def __init__(self, path, op, val):
"""Initialize the condition.
Arguments:
path -- the path to a specific attribute of a stream
op -- the operator to be checked in the condition
val -- the value to check the condition against.
"""
self.path = path
self.op = op
self.val = val
if isinstance(self.val, InPolygon) or isinstance(self.val, InCircle):
if op not in ('==', ):
raise FlareSyntaxError(
"Only `==` operator can be used with regions")
def span(self, *q, **kwargs):
"""A span of time where a set of conditions is continuously satisfied.
Conditions can be defined across one or more streams.
Keyword arguments:
min -- The minimum valid span duration `delta()`.
max -- The maximum valid span duration `delta()`.
exactly -- The exact valid span duration `delta()`.
within -- The maximum distance in time between the end of the
previous span and the start of this span.
after -- The minimum distance in time between the end of the
previous span and the start of this span.
"""
for k in kwargs:
if k not in ['min', 'max', 'exactly']:
raise FlareSyntaxError(
'first span in a select supports only '
'`min`, `max` and `exactly` duration arguments')
if self._query:
raise FlareSyntaxError("Use .then method")
else:
self._query.append(Span(*q, **kwargs))
return self
def __init__(self, *streams, **kwargs):
self.projs = []
for s in streams:
if isinstance(s, Stream):
self.projs.append(Proj(s))
elif isinstance(s, tuple):
for x in s:
if isinstance(x, Stream):
self.projs.append(Proj(x))
elif isinstance(x, Proj):
self.projs.append(x)
elif isinstance(s, Proj):
self.projs.append(s)
else:
raise FlareSyntaxError(
"Invalid projection type in `returning`")
self.default = kwargs.get('default', True)
def __call__(self):
"""Generate AST code from the switch."""
if not self._stream:
raise FlareSyntaxError("Switch must be bound to stream")
cds = []
for s in self._query:
if len(s) < 1:
expr = {'expr': True}
else:
expr = s[-1]()
for x in s[-2::-1]:
expr = {'expr': '&&', 'args': [x(), expr]}
cds.append(expr)
if len(cds) == 0:
cds = [{'expr': True}, {'expr': True}]
elif len(cds) == 1:
cds.insert(0, {'expr': True})
return {'type': 'switch', 'conds': cds, 'stream': self._stream()}
def then(self, *q, **kwargs):
"""A span of time following the previous span satisfying new conditions.
Conditions can be defined across one or more streams and must also
be satisfied continuously.
Keyword arguments:
min -- The minimum valid span duration `delta()`.
max -- The maximum valid span duration `delta()`.
exactly -- The exact valid span duration `delta()`.
within -- The maximum distance in time between the end of
the previous span and the start of this span.
after -- The minimum distance in time between the end of
the previous span and the start of this span.
"""
if not self._query:
raise FlareSyntaxError("Use .span method to start select")
else:
if "after" not in kwargs and "within" not in kwargs:
kwargs["within"] = delta(seconds=0)
self._query.append(Span(*q, **kwargs))
return self
def __init__(self, stream, proj=True):
if not isinstance(stream, Stream):
raise FlareSyntaxError(
"returning dict top-level keys must be streams.")
self.stream = stream
self.proj = proj