class Map(Type):
"""Map type."""
key = TypedField(Type)
value = TypedField(Type)
def __str__(self):
return '{{{}: {}}}'.format(self.key, self.value)
def smaller_cmp(self, other):
if type(self) != type(other):
return NotImplemented
return (self.key.issmaller(other.key) and
self.value.issmaller(other.value))
def join_helper(self, other, *, inverted=False):
top = Top if not inverted else Bottom
if type(self) != type(other):
return top
new_key = self.key.join(other.key, inverted=inverted)
new_value = self.value.join(other.value, inverted=inverted)
return self._replace(key=new_key, value=new_value)
def widen_helper(self, height):
new_key = self.key.widen(height - 1)
new_value = self.value.widen(height - 1)
return self._replace(key=new_key, value=new_value)
class DictType(Type):
kt = TypedField(Type)
vt = TypedField(Type)
# Contravariant key types were also considered as a possibility.
# This would affect each of the helpers below.
def __str__(self):
return '{' + str(self.kt) + ': ' + str(self.vt) + '}'
def issubtype_helper(self, other):
if type(self) != type(other):
return False
return (self.kt.issubtype(other.kt) and self.vt.issubtype(other.vt))
def join_helper(self, other, *, inverted=False):
if type(self) != type(other):
return toptype if not inverted else bottomtype
new_kt = self.kt.join(other.kt, inverted=inverted)
new_vt = self.vt.join(other.vt, inverted=inverted)
return self._replace(kt=new_kt, vt=new_vt)
def match_against_helper(self, other):
return [(self.kt, self.kt), (other.vt, other.vt)]
def expand(self, store):
new_kt = self.kt.expand(store)
new_vt = self.vt.expand(store)
return self._replace(kt=new_kt, vt=new_vt)
def widen_helper(self, limit):
new_kt = self.kt.widen(limit - 1)
new_vt = self.vt.widen(limit - 1)
return self._replace(kt=new_kt, vt=new_vt)
class TClause_NoTC(TClause):
"""TClause without type checks in emitted code."""
tup = TypedField(str)
elts = TypedField(str, seq=True)
typecheck = False
class SingletonClause(Clause, ABCStruct):
"""An enumerator over a singleton set, i.e., that binds its
left-hand side to a single value.
"""
kind = Clause.KIND_ENUM
robust = False
lhs = TypedField(str, seq=True)
"""Enumeration variables."""
val = TypedField(L.expr)
"""Expression computing value of singleton element."""
@classmethod
def from_expr(cls, node):
"""Construct from a condition expression of form
<vars> == <rel>
"""
checktype(node, L.AST)
left, op, val = L.get_cmp(node)
checktype(op, L.Eq)
lhs = L.get_vartuple(left)
return cls(lhs, val)
@classmethod
def from_AST(cls, node, factory):
"""Construct from Enumerator node of form
<vars> in {<expr>}
"""
checktype(node, L.Enumerator)
lhs = L.get_vartuple(node.target)
val = L.get_singletonset(node.iter)
return cls(lhs, val)
def __init__(self, lhs, val):
self.enumlhs = self.lhs
self.enumrel = None
self.vars = self.enumvars
def to_AST(self):
return L.Enumerator(L.tuplify(self.lhs, lval=True), L.Set(
(self.val, )))
def rate(self, bindenv):
return Rate.CONSTANT
def get_code(self, bindenv, body):
mask = Mask.from_vars(self.lhs, bindenv)
bvars, uvars, _eqs = mask.split_vars(self.lhs)
return make_tuplematch(self.val, mask, bvars, uvars, body)
class IndefImgset(Cost):
"""Indefinite image set, i.e., the size of the largest image set
under any key for a given relation and mask.
"""
rel = TypedField(str)
mask = TypedField(L.mask)
def __str__(self):
return '{}_{}'.format(self.rel, self.mask.m)
class Filter(Struct):
_immutable = False
i = TypedField(int)
"""Index of clause for which this filter is generated."""
name = TypedField(str)
"""Name of this filter."""
clause = TypedField(L.clause)
"""Clause that this filter is based on."""
preds = TypedField(str, seq=True)
"""Names of predecessor tags for this filter."""
class Tag(Struct):
_immutable = False
i = TypedField(int)
"""Index of clause for which this tag is generated."""
name = TypedField(str)
"""Name of this tag."""
tag_var = TypedField(str)
"""Query variable controlled by this tag."""
clause = TypedField(L.clause)
"""Clause that this tag projects."""
class WrapInvariant(Struct):
"""Wrap invariant."""
rel = TypedField(str)
"""Name of variable holding the relation to be maintained."""
oper = TypedField(str)
"""Name of variable holding the operand relation."""
unwrap = TypedField(bool)
"""True for Unwrap, False for Wrap."""
def get_maint_func_name(self, op):
op_name = L.set_update_name(op)
return N.get_maint_func_name(self.rel, self.oper, op_name)
class Task(Struct):
"""A single transformation task."""
display_name = TypedField(str)
"""Display name for status printing."""
input_name = TypedField(str)
"""Input filename."""
output_name = Field()
"""Output filename, or None if no transformation."""
nopts = Field()
"""Normal options."""
qopts = Field()
"""Query options."""
class LookupClause(EnumClause, ABCStruct):
"""An enumerator over a singleton set of an SMLookup node.
Basically acts like a normal EnumClause, but the forward
direction takes constant time due to the functional
dependency from keys to value.
"""
lhs = TypedField(str, seq=True)
"""Enumeration variables."""
rel = TypedField(str)
"""Name of iterated relation."""
@classmethod
def from_AST(cls, node, factory):
"""Construct from an Enumerator node of form
var in {<rel>.smlookup(<mask>, <key vars>)}
"""
checktype(node, L.Enumerator)
var = L.get_name(node.target)
sm = L.get_singletonset(node.iter)
checktype(sm, L.SMLookup)
rel = L.get_name(sm.target)
mask = Mask(sm.mask)
keyvars = L.get_vartuple(sm.key)
# Ensure the mask is consistent with how it's used.
if mask != Mask.from_keylen(len(keyvars)):
raise TypeError
lhs = keyvars + (var, )
return cls(lhs, rel)
def to_AST(self):
mask = Mask.from_keylen(len(self.lhs) - 1)
keyvars = self.lhs[:-1]
var = self.lhs[-1]
sm = L.SMLookup(L.ln(self.rel),
mask.make_node().s, L.tuplify(keyvars), None)
return L.Enumerator(L.sn(var), L.Set((sm, )))
def rewrite_subst(self, subst, factory):
# The normal rewriting won't get the smlookup keys.
new_lhs = apply_subst_tuple(self.lhs, subst)
return self._replace(lhs=new_lhs)
def rate(self, bindenv):
mask = Mask.from_vars(self.lhs, bindenv)
if mask.is_keymask:
return Rate.CONSTANT
return super().rate(bindenv)
class DefImgsetCost(Cost):
rel = TypedField(str)
mask = TypedField(Mask)
key = TypedField(str, seq=True)
def __str__(self):
return '{}_{}[{}]'.format(self.rel, self.mask,
', '.join(self.key))
def to_indef(self):
"""Return the indefinite image set cost that generalizes
this cost.
"""
return IndefImgsetCost(self.rel, self.mask)
class USet(Struct):
kind = KIND_USET
i = TypedField(int)
"""Index of query enumerator where the subquery is iterated over."""
name = TypedField(str)
"""Name of associated demand name."""
vars = TypedField(str, seq=True)
"""Vars that get passed to the demand functions as parameters."""
preds = Field()
"""Names of predecessor tags, or None if using clauses."""
pred_clauses = Field()
"""Predecessor clauses, or None if using tags."""
reorder_i = TypedField(int)
"""Relative order for demand graph."""
class Sum(Cost):
"""Sum of a sequence of costs."""
terms = TypedField(Cost, seq=True)
def __str__(self):
return '(' + ' + '.join(str(t) for t in self.terms) + ')'
class Sequence(Type):
"""Sequence of homogeneous elements. Covariant in element type."""
elt = TypedField(Type)
def __str__(self):
return 'Seq<' + str(self.elt) + '>'
def smaller_cmp(self, other):
# Two Sequence-based types are comparable if they are of the
# same Sequence subtype or if one of the types is a Sequence
# proper. In either case it then comes down to the element type.
if (type(self) != type(other) and
type(other) != Sequence):
return NotImplemented
return self.elt.issmaller(other.elt)
def join_helper(self, other, *, inverted=False):
# The join of two distinct Sequence-based types is a Sequence
# proper.
top = Top if not inverted else Bottom
if (type(self) != type(other) and
not issubclass(type(other), Sequence)):
return top
new_elt = self.elt.join(other.elt, inverted=inverted)
if type(self) == type(other):
return self._replace(elt=new_elt)
else:
return Sequence(new_elt) if not inverted else Bottom
def widen_helper(self, height):
new_elt = self.elt.widen(height - 1)
return self._replace(elt=new_elt)
class SeqType(Type):
et = TypedField(Type)
brackets = '??'
def __str__(self):
return self.brackets[0] + str(self.et) + self.brackets[1]
def issubtype_helper(self, other):
if type(self) != type(other):
return False
return self.et.issubtype(other.et)
def join_helper(self, other, inverted=False):
if type(self) != type(other):
return toptype if not inverted else bottomtype
new_et = self.et.join(other.et, inverted=inverted)
return self._replace(et=new_et)
def match_against_helper(self, other):
return [(self.et, other.et)]
def expand(self, store):
new_et = self.et.expand(store)
return self._replace(et=new_et)
def widen_helper(self, limit):
new_et = self.et.widen(limit - 1)
return self._replace(et=new_et)
class Min(Cost):
"""Minimum of a sequence of costs."""
terms = TypedField(Cost, seq=True)
def __str__(self):
return 'min(' + ', '.join(str(t) for t in self.terms) + ')'
class Name(Cost):
"""Atomic cost, e.g. a domain size or a relation size."""
name = TypedField(str)
def __str__(self):
return self.name
class Tuple(Type):
"""Tuple type. For tuples of the same arity, covariant in the
component types.
"""
elts = TypedField(Type, seq=True)
def __str__(self):
return '(' + ', '.join(str(e) for e in self.elts) + ')'
def smaller_cmp(self, other):
if type(self) != type(other):
return NotImplemented
if len(self.elts) != len(other.elts):
return NotImplemented
return all(e1.issmaller(e2)
for e1, e2 in zip(self.elts, other.elts))
def join_helper(self, other, *, inverted=False):
top = Top if not inverted else Bottom
if type(self) != type(other):
return top
if len(self.elts) != len(other.elts):
return top
new_elts = [e1.join(e2, inverted=inverted)
for e1, e2 in zip(self.elts, other.elts)]
return self._replace(elts=new_elts)
def widen_helper(self, height):
new_elts = [e.widen(height - 1) for e in self.elts]
return self._replace(elts=new_elts)
class IncAggr(Struct):
"""Info for incrementalizing an aggregate query."""
aggr = TypedField(L.Aggregate)
"""Aggregate node."""
spec = TypedField(AggrSpec)
"""Aggregate query info."""
name = TypedField(str)
"""Result set name."""
demname = Field()
"""Aggregate demand name, or None if not using demand."""
uset_lru = Field()
"""None or an integer bound for LRU cache size."""
half_demand = TypedField(bool)
"""If using demand and this is True, use the "half-demand"
strategy.
"""
@property
def has_demand(self):
return self.demname is not None
@property
def tracks_counts(self):
# Counts are needed to know when to remove entries from the
# aggregate result map. If we're using the normal demand
# strategy, we only remove entries when keys become undemanded,
# so counts aren't needed.
return not (self.has_demand and not self.half_demand)
def __init__(self, aggr, spec, name, demname, uset_lru, half_demand):
self.params = params = tuple(spec.params)
"""Aggregate parameters (same as operand parameters).
Also same as aggregate demand parameters.
"""
self.aggrmask = Mask.from_keylen(len(params))
"""Aggregate result retrieval mask."""
self.oper_deltamask = spec.relmask.make_delta_mask()
"""Mask for doing delta test upon change to aggregate operand."""
assert not (spec.has_oper_demand and not self.has_demand), \
'Can\'t have non-demand-driven aggregate over demand-driven ' \
'operand'
assert not (half_demand and not self.has_demand), \
'Can\'t use half-demand strategy when not using demand at all'
class ObjType(Type):
name = TypedField(str)
def __str__(self):
return self.name
def matches_helper(self, other):
return False
class SetFromMapInvariant(Struct):
"""SetFromMap invariant."""
# The map key must be a tuple. The mask must be a mapmask with a
# number of bound components equal to the arity of the map key.
rel = TypedField(str)
"""Name of variable holding the relation to be created."""
map = TypedField(str)
"""Name of map being indexed."""
mask = TypedField(L.mask)
"""Mask for relating the map to the set."""
def __init__(self, rel, map, mask):
assert L.is_mapmask(mask)
def get_maint_func_name(self, op):
assert op in ['assign', 'delete']
return N.get_maint_func_name(self.rel, self.map, op)
class Primitive(Type):
"""Built-in type."""
# Note that t holds a Python class, not a Type.
t = TypedField(type)
def __str__(self):
return self.t.__name__
class Refine(Type):
name = TypedField(str)
base = TypedField(Type)
def __str__(self):
return '{}:{}'.format(self.name, self.base)
def smaller_cmp(self, other):
return self.base.issmaller(other)
def join_helper(self, other, *, inverted=False):
# Since we don't have Union types, the only direct ancestor of
# this type is the base. Therefore, the join of this type with
# any other type T is the same as the join of the base with T.
#
# The only descendants of this type are Bottom and other Refine
# types. The Refine types only have one parent, so they don't
# have any ancestors that are incomparable with this type.
# Consequently, the meet of this type with any incomparable
# type is Bottom.
if not inverted:
return self.base.join(other, inverted=inverted)
else:
return Bottom
def widen_helper(self, height):
# Suppose this type is Refine<name, T>, and that widening is
# needed. Let U be a widened version of T with T <= U.
#
# We can't return Refine<..., U> as our widening, because it is
# not generally true that Refine<..., T> <= Refine<..., U>.
# Instead, our widening is just T itself.
widened_base = self.base.widen(height - 1)
if widened_base == self.base:
# Turns out widening is not even needed.
return self
else:
# Something has to give. Return the base with widening, but
# give it one more level of leeway since we're getting rid
# of ourselves.
return self.base.widen(height)
class AuxmapInvariant(Struct):
"""Auxiliary map invariant."""
map = TypedField(str)
"""Name of variable holding the map to be created."""
rel = TypedField(str)
"""Name of relation being indexed."""
mask = TypedField(L.mask)
"""Mask for the indexing."""
unwrap_key = TypedField(bool)
"""Whether the bound part is a single unwrapped component."""
unwrap_value = TypedField(bool)
"""Whether the unbound part is a single unwrapped component."""
def __init__(self, map, rel, mask, unwrap_key, unwrap_value):
assert not (unwrap_key and mask.m.count('b') > 1)
assert not (unwrap_value and mask.m.count('u') > 1)
def get_maint_func_name(self, op):
op_name = L.set_update_name(op)
return N.get_maint_func_name(self.map, self.rel, op_name)
class DefImgset(Cost):
"""Definite image set, i.e., the size of a particular image set
under a given sequence of key variables, for the given relation and
mask.
"""
rel = TypedField(str)
mask = TypedField(L.mask)
key = TypedField(str, seq=True)
def __init__(self, rel, mask, key):
assert mask.m.count('b') == len(key)
def __str__(self):
return '{}_{}[{}]'.format(self.rel, self.mask.m, ', '.join(self.key))
def to_indef(self):
"""Return the indefinite image-set cost that generalizes this
cost.
"""
return IndefImgset(self.rel, self.mask)
class SumCost(Cost):
terms = TypedField(Cost, seq=True)
@classmethod
def from_sums(cls, costs):
"""Form as the concatenation of other SumCosts."""
assert all(isinstance(c, SumCost) for c in costs)
return SumCost(tuple(chain.from_iterable(c.terms for c in costs)))
def __str__(self):
return '(' + ' + '.join(str(s) for s in self.terms) + ')'
class ProductCost(Cost):
terms = TypedField(Cost, seq=True)
@classmethod
def from_products(cls, costs):
"""Form as the concatenation of other ProductCosts."""
assert all(isinstance(c, ProductCost) for c in costs)
return ProductCost(tuple(chain.from_iterable(c.terms for c in costs)))
def __str__(self):
return '(' + '*'.join(str(t) for t in self.terms) + ')'
class RestrictiveType(Type):
name = TypedField(str)
base = TypedField(Type)
def __str(self):
return self.name
def issubtype_helper(self, other):
return self.base.issubtype(other)
def matches_helper(self, other):
return False
def join_helper(self, other, *, inverted=False):
# My join with any type that's not directly comparable
# is the same as my base's join with that type, since
# my base is my only direct ancestor.
#
# My meet with any type that's not directly comparable
# is bottom, since the only possible non-bottom subtypes
# are other refinements, which would have no ancestors
# that are incomparable to me.
if not inverted:
return self.base.join(other, inverted=inverted)
else:
return bottomtype
def expand(self, store):
new_base = self.base.expand(store)
return self._replace(base=new_base)
def widen_helper(self, limit):
# Rather than lose information in the base, it's probably
# better to just replace ourselves with the base.
widened_base = self.base.widen(limit - 1)
if self.base != widened_base:
new_type = self.base.widen(limit)
else:
new_type = self
return new_type
class DeltaInfo(Struct):
"""Information about maintenance joins."""
rel = TypedField(str)
"""Delta relation."""
elem = TypedField(L.AST)
"""Delta element expression AST."""
lhs = TypedField(str, seq=True)
"""Delta clause LHS identifier list."""
op = TypedField(str)
"""'add' or 'remove'."""
@classmethod
def from_options(cls, options):
"""Construct from comprehension options dict.
If delta info isn't provided, return None instead
of an instance.
"""
if options is None or '_deltarel' not in options:
return None
rel = options['_deltarel']
elem = options['_deltaelem']
elem = L.pe(elem)
lhs = options['_deltalhs']
lhs = L.get_vartuple(L.pe(lhs))
op = options['_deltaop']
return cls(rel, elem, lhs, op)
def __init__(self, rel, elem, lhs, op):
assert op in ['add', 'remove']
def updateopts(self, options):
"""Return a modified options dict with the delta keys set."""
options = dict(options)
options['_deltarel'] = self.rel
options['_deltaelem'] = L.ts(self.elem)
options['_deltalhs'] = L.ts(L.tuplify(self.lhs, lval=True))
options['_deltaop'] = self.op
return options
class CondClause(Clause, ABCStruct):
"""A condition expression clause."""
kind = Clause.KIND_COND
cond = TypedField(L.expr)
"""Condition expression."""
@classmethod
def from_AST(cls, node, factory):
"""Construct from expression node."""
checktype(node, L.expr)
return cls(node)
def __init__(self, cond):
self.vars = tuple(L.VarsFinder.run(cond, ignore_functions=True))
if L.is_vareqcmp(cond):
self.eqvars = L.get_vareqcmp(cond)
else:
self.eqvars = None
def to_AST(self):
return self.cond
def fits_string(self, bindenv, s):
return self.cond == L.pe(s)
def rate(self, bindenv):
if set(self.vars).issubset(bindenv):
return Rate.CONSTANT
else:
return Rate.UNRUNNABLE
def get_code(self, bindenv, body):
assert set(self.vars).issubset(bindenv)
code = L.pc('''
if COND:
BODY
''',
subst={
'COND': self.cond,
'<c>BODY': body
})
return code