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vat.py
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vat.py
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from base import *
from globs import *
from types_builtin import app_map, subst
# Sure could use graphs here!
VatContents = DT('VatContents', ('copiedExtrinsics', ['*Extrinsic']),
('replacements', {'a': 'a'}),
('transmute', {'a': 'a'}))
VAT = new_env('VAT', VatContents)
Original = new_extrinsic('Original', 'a')
def set_orig(clone, orig):
# Don't need to recurse since there's only one level of clones
if has_extrinsic(Original, orig):
orig = extrinsic(Original, orig)
add_extrinsic(Original, clone, orig)
def orig_loc(obj):
# Ugh, I don't like the conditional check...
if has_extrinsic(Original, obj):
obj = extrinsic(Original, obj)
return extrinsic(Location, obj)
def original(extr, obj):
return extrinsic(extr, extrinsic(Original, obj))
def original_has(extr, obj):
if not has_extrinsic(Original, obj):
return False
return has_extrinsic(extr, extrinsic(Original, obj))
def in_vat(func):
return in_env(VAT, VatContents([], {}, False), func)
# Clone structured data, recording information about its clone in the vat
def clone(src, extrinsics):
env(VAT).copiedExtrinsics = extrinsics
return clone_structured(src)
def clone_structured(src, apps=None):
ctor = instance_ctor(src)
fs = []
for field in ctor.fields:
fnm = extrinsic(Name, field)
ft = field.type
if apps:
ft = subst(apps, ft)
fs.append(clone_by_type(getattr(src, fnm), ft))
ctor_cls = extrinsic(TrueRepresentation, ctor)
vat = env(VAT)
if vat.transmute:
destData = vat.transmute.get(extrinsic(FormSpec, SUPERS[ctor_cls]))
if destData is not None:
ctor = transmuted_ctor(src, destData)
ctor_cls = extrinsic(TrueRepresentation, ctor)
o = ctor_cls(*fs)
for extr in vat.copiedExtrinsics:
if has_extrinsic(extr, src):
add_extrinsic(extr, o, extrinsic(extr, src))
if in_extrinsic_scope(Original):
set_orig(o, src)
vat.replacements[src] = o
return o
def clone_by_type(src, t):
cls = t.__class__
if cls is TVar:
assert isinstance(Structured, src), \
"Can't clone unstructured %r without type info" % (src,)
return clone_structured(src)
elif cls in (TPrim, TFunc, TWeak):
return src
elif cls is TTuple:
assert isinstance(src, tuple)
return tuple(clone_by_type(v, tt) for v, tt in ezip(src, t.tupleTypes))
elif cls is TData:
assert isinstance(src, extrinsic(TrueRepresentation, t.data)), \
"Expected %s, got: %r" % (t.data, obj)
apps = t.appTypes and app_map(t.data, t.appTypes)
return clone_structured(src, apps)
elif cls is TArray:
assert isinstance(src, list)
return [clone_by_type(s, t.elemType) for s in src]
else:
assert False, "Bad type to clone: %r" % (t,)
def instance_ctor(obj):
ctors = t_DT(type(obj)).data.ctors
return ctors[obj._ctor_ix if len(ctors) > 1 else 0]
def transmuted_ctor(obj, destData):
ctors = destData.ctors
ix = obj._ctor_ix if len(ctors) > 1 else 0
assert ix < len(ctors), "Don't know how to transmute %s!" % (obj,)
return ctors[ix]
# Update an object's weak references to point at new clones from this vat
def rewrite(obj):
return rewrite_by_type(obj, t_DT(type(obj)))
def rewrite_by_type(obj, t):
cls = t.__class__
if cls is TVar:
assert isinstance(Structured, obj), \
"Can't rewrite unstructured %r without type info" % (obj,)
rewrite_by_type(obj, t_DT(type(obj)))
elif cls in (TPrim, TFunc):
pass
elif cls is TTuple:
assert isinstance(obj, tuple)
for v, tt in ezip(obj, t.tupleTypes):
assert not isinstance(tt, TWeak), "TODO"
rewrite_by_type(v, tt)
elif cls is TData:
assert isinstance(obj, extrinsic(TrueRepresentation, t.data)), \
"Expected %s, found %s %s" % (t.data, type(obj), obj)
apps = t.appTypes and app_map(t.data, t.appTypes)
ctor = instance_ctor(obj)
repls = env(VAT).replacements
for field in ctor.fields:
fnm = extrinsic(Name, field)
ft = field.type
if apps:
ft = subst(apps, ft)
val = getattr(obj, fnm)
if isinstance(ft, TWeak):
if val in repls:
setattr(obj, fnm, repls[val])
else:
rewrite_by_type(val, ft)
elif cls is TArray:
et = t.elemType
assert isinstance(obj, list)
if isinstance(et, TWeak):
repls = env(VAT).replacements
for i, w in enumerate(obj):
if w in repls:
obj[i] = repls[w]
else:
for s in obj:
rewrite_by_type(s, et)
elif cls is TWeak:
assert False, "Shouldn't get here (should be rewritten in other cases)"
else:
assert False, "Bad type to rewrite: %r" % (t,)
# Clone a structured object, changing its type in the process
def transmute(obj, mapping, extrinsics):
vat = env(VAT)
vat.copiedExtrinsics = extrinsics
vat.transmute = dict((src.data, dest.data)
for src, dest in mapping.iteritems())
obj = clone_structured(obj)
vat.transmute = False
return obj
# AST visitor&mutator (not really vat)
# Env+class is redundant; could just put this all in the class.
# But this is plumbing anyway
VISIT = new_env('VISIT', None)
def visit(visitor, obj, t):
inst = visitor()
inst.obj = inst.t = inst.fts = None
if isinstance(t, basestring):
t = parse_type(t)
in_env(VISIT, inst, lambda: visit_by_type(obj, t))
class Visitor(object):
def visit(self, *path):
obj, t = self.obj, self.t
for field in path:
if isinstance(field, int):
assert isinstance(t, TArray), "Can't index %s" % (t,)
obj = obj[field]
t = t.elemType
continue
assert field in self.fts, \
"%s is not a field {%s}" % (field, ', '.join(self.fts))
t = self.fts[field]
# Catch some stupidity
if len(path) == 1:
assert t is not None, "Already visited this field!"
self.fts[field] = None
assert not isinstance(t, TWeak), \
"%s is weak and won't be visited" % (field,)
obj = getattr(obj, field)
return visit_by_type(obj, t, bool(path))
def visit_by_type(obj, t, customVisitors=True):
cls = t.__class__
if cls in (TVar, TPrim, TFunc, TWeak):
pass
elif cls is TTuple:
assert isinstance(obj, tuple)
for v, tt in ezip(obj, t.tupleTypes):
visit_by_type(v, tt)
elif cls is TData:
data = t.data
assert isinstance(obj, extrinsic(TrueRepresentation, data)), \
"Expected %s, got %s %s" % (data, type(obj), obj)
apps = t.appTypes and app_map(data, t.appTypes)
visitor = env(VISIT)
ctor = extrinsic(FormSpec, type(obj))
fts = dict((extrinsic(Name, f), subst(apps,f.type) if apps else f.type)
for f in ctor.fields)
if customVisitors:
custom = getattr(visitor, extrinsic(Name, ctor), None)
if custom is None:
custom = getattr(visitor, 't_'+extrinsic(Name, data), None)
if custom is not None:
# Scope field types for recursive visiting
old = visitor.obj, visitor.t, visitor.fts
visitor.obj, visitor.t, visitor.fts = obj, t, fts
custom(obj)
visitor.obj, visitor.t, visitor.fts = old
return
# Default to recursive visits
for field in ctor.fields:
fnm = extrinsic(Name, field)
ft = fts[fnm]
if not isinstance(ft, TWeak):
visit_by_type(getattr(obj, fnm), ft)
elif cls is TArray:
assert isinstance(obj, list)
if not isinstance(t.elemType, TWeak):
for o in obj:
visit_by_type(o, t.elemType)
else:
assert False, "Bad type to visit: %r" % (t,)
MUTATE = new_env('MUTATE', None)
def mutate(mutator, obj, t):
inst = mutator()
inst.obj = inst.t = inst.fts = None
if isinstance(t, basestring):
t = parse_type(t)
return in_env(MUTATE, inst, lambda: mutate_by_type(obj, t))
class Mutator(object):
def mutate(self, *path):
obj, t = self.obj, self.t
for field in path:
if isinstance(field, int):
assert isinstance(t, TArray), "Can't index %s" % (t,)
obj = obj[field]
t = t.elemType
continue
assert field in self.fts, \
"%s is not a field {%s}" % (field, ', '.join(self.fts))
t = self.fts[field]
# Catch some stupidity
if len(path) == 1:
assert t is not None, "Already mutated this field!"
self.fts[field] = None
assert not isinstance(t, TWeak), \
"%s is weak and won't be mutated" % (field,)
obj = getattr(obj, field)
return mutate_by_type(obj, t, bool(path))
def mutate_by_type(obj, t, customMutators=True):
cls = t.__class__
if cls in (TVar, TPrim, TFunc, TWeak):
return obj
elif cls is TTuple:
assert isinstance(obj, tuple)
return tuple(rewrite_by_type(v, tt)
for v, tt in ezip(obj, t.tupleTypes))
elif cls is TData:
data = t.data
assert isinstance(obj, extrinsic(TrueRepresentation, data)), \
"Expected %s, got %r: %r" % (data, type(obj), obj)
apps = t.appTypes and app_map(data, t.appTypes)
mutator = env(MUTATE)
ctor = extrinsic(FormSpec, type(obj))
fts = dict((extrinsic(Name, f), subst(apps,f.type) if apps else f.type)
for f in ctor.fields)
if customMutators:
custom = getattr(mutator, extrinsic(Name, ctor), None)
if custom is None:
custom = getattr(mutator, 't_'+extrinsic(Name, data), None)
if custom is not None:
# Scope field types for recursive mutatino
old = mutator.obj, mutator.t, mutator.fts
mutator.obj, mutator.t, mutator.fts = obj, t, fts
obj = custom(obj)
mutator.obj, mutator.t, mutator.fts = old
return obj
# Default to recursive mutation
for field in ctor.fields:
fnm = extrinsic(Name, field)
ft = fts[fnm]
if not isinstance(ft, TWeak):
val = getattr(obj, fnm)
setattr(obj, fnm, mutate_by_type(val, ft))
return obj
elif cls is TArray:
et = t.elemType
assert isinstance(obj, list)
if isinstance(et, TWeak):
return obj
return [mutate_by_type(o, et) for o in obj]
else:
assert False, "Bad type to mutate: %r" % (t,)
# COMBINATORIAL EXPLOSIONS
REIFIED_MONOTYPES = {}
def cement_type(t):
key = type_key(t)
if key in CONCRETE_TYPES:
return CONCRETE_TYPES[key]
else:
assert False
def type_key(t):
m = match(t)
if m('TPrim(prim)'):
return prim_key(m.prim)
elif m('TData(dt, ts)'):
nm = extrinsic(Name, dt)
return '%s(%s)' % (nm, ', '.join(type_key(a) for a in m.ts))
elif m('TArray(t, _)'): # kind?
return '[%s]' % (type_key(m.t),)
elif m('TWeak(t)'):
return '*%s' % (type_key(m.t),)
elif m('TTuple(ts)'):
return 't(%s)' % (', '.join(type_key(t) for t in m.ts),)
elif m('TVar(tv)'):
return 'ax%x' % (id(tv),)
elif m('TFunc(ps, r, _)'):
ts = map(m.ps, type_key)
ts.append(match(m.r, ('Ret(t)', type_key),
('Void()', lambda: 'void'),
('Bottom()', lambda: 'bottom')))
return 'f(%s)' % (' -> '.join(ts),)
else:
assert False
def prim_key(p):
m = match(p)
if m('PInt()'): return 'int'
elif m('PFloat()'): return 'float'
elif m('PStr()'): return 'str'
elif m('PChar()'): return 'char'
elif m('PBool()'): return 'bool'
else: assert False
# vi: set sw=4 ts=4 sts=4 tw=79 ai et nocindent: