def let(module, is_rec, seq, body):
clc = module.clc
with clc.resume_scope():
outer_scope = clc.scope = clc.scope.sub_scope()
types = []
for loc, name, annotation, _ in seq:
if annotation:
type_bind = Typing(clc).eval(annotation)
else:
type_bind = new_var(clc, name)
types.append(type_bind)
if is_rec:
_, name = sexpr.unloc(name)
sym_bind = outer_scope.enter(name)
tenv[sym_bind] = type_bind
block = []
syms = []
for (loc, name, annotation,
bound), sym_type in zip(seq, types):
_, name = sexpr.unloc(name)
level = tc_state.push_level()
inner_scope = clc.scope = outer_scope.sub_scope()
if is_rec:
sym_bind = inner_scope.require(name)
else:
sym_bind = inner_scope.enter(name)
tenv[sym_bind] = sym_type
syms.append(sym_bind)
t_inst = te.fresh(tc_state.new_var, sym_type)
t_inst = inst(t_inst, rigid=True)[1]
bound = module.eval_with_implicit(bound)
tc_state.unify(t_inst, bound.type)
gen_type = generalise_type(tc_state,
t_inst,
loc=loc,
filename=clc.filename,
level=level)
bound.type = gen_type
unify(gen_type, sym_type)
block.append(ignore(ir.Set(sym_bind, bound)))
# level = tc_state.push_level()
clc.scope = inner_scope.sub_scope()
body = module.eval(body)
# block.append(body)
# body.type = generalise_type(tc_state, body.type, loc=clc.location, filename=clc.filename, level=level)
return ir.Expr(type=body.type, expr=ir.Block(block))
def lam(module, arg, type, ret):
loc, name = sexpr.unloc(arg)
clc = module.clc
outer_scope = clc.scope
filename = clc.filename
path = clc.path
if type:
type_arg = tc_state.infer(Typing(clc).eval(type))
else:
type_arg = new_var(clc, name)
with clc.resume_scope():
# level = tc_state.push_level()
inner_scope = outer_scope.sub_scope(hold_bound=True)
clc.scope = inner_scope
sym_arg = inner_scope.enter(name)
tenv[sym_arg] = type_arg
ret = module.eval(ret)
lam_type = te.Arrow(
type_arg, ret.type
) # lam_type = generalise_type(tc_state, lam_type, loc=loc, filename=filename, level=level)
name = "{} |{}|".format(path, name)
sym_arg = ir.Fun(name, filename, sym_arg, ret)
return ir.Expr(type=lam_type, expr=sym_arg)
def record(module, pairs, row):
_, pairs = sexpr.unloc(pairs)
if row:
row_t = te.RowPoly(module.eval(row))
else:
row_t = te.empty_row
fields = [(k, module.eval(v)) for k, v in pairs]
row_t = te.row_from_list(fields, row_t)
return te.Record(row_t)
def define(self, is_rec, name, annotated, bound):
module = Express(self.clc)
loc, name = sexpr.unloc(name)
clc = self.clc
outer_scope = clc.scope
if is_rec:
sym_def = outer_scope.require(name)
else:
sym_def = outer_scope.shadow(name) # may shadow
with clc.resume_scope():
inner_scope = outer_scope.sub_scope()
clc.scope = inner_scope
if annotated:
t1 = infer(Typing(clc).eval(annotated))
if sym_def in tenv:
unify(inst(tenv[sym_def])[1], inst(t1)[1])
else:
tenv[sym_def] = t1
else:
if sym_def in tenv:
t1 = infer(tenv[sym_def])
else:
new_var = tc_state.new_var(Var=types.Var,
loc=loc,
filename=clc.filename,
name=sym_def.name)
tenv[sym_def] = t1 = new_var
level = tc_state.push_level()
bound: ir.Expr = module.eval(bound)
t1_inst = te.fresh(tc_state.new_var, infer(t1))
t1_inst = inst(t1_inst, rigid=True)[1]
t2_inst = bound.type = inst(infer(bound.type))[1]
resolve_instance_(outer_scope, bound)
unify(t1_inst, t2_inst)
bound.type = generalise_type(tc_state,
t2_inst,
loc=loc,
filename=clc.filename,
level=level)
unify(bound.type, t1)
exp_def = ir.Set(sym_def, bound)
return ignore(exp_def)
def exist(module, bound_vars: tuple, monotype):
bound_vars_ = set(bound_vars)
if len(bound_vars) != len(bound_vars_):
raise excs.DuplicatedNamedTypeVar(bound_vars_)
bound_vars = bound_vars_
filename = module.clc.filename
scope = module.clc.scope
for n in bound_vars:
loc, n = sexpr.unloc(n)
sym = scope.enter(n)
tvar = tc_state.user_var(Var=types.Var,
loc=loc,
filename=filename,
name=n)
tenv[sym] = te.App(types.type_type, tvar)
return module.eval(monotype)
def forall(module, unbound_fresh_decls: typing.Tuple[str, ...],
polytype):
fresh_vars_ = set(unbound_fresh_decls)
if len(fresh_vars_) != len(unbound_fresh_decls):
raise excs.DuplicatedNamedTypeVar(fresh_vars_)
unbound_fresh_decls = fresh_vars_
clc = module.clc
forall_scope = types.ForallScope(clc.location, clc.filename)
bound_vars = []
with clc.resume_scope():
clc.scope = sub_scope = clc.scope.sub_scope()
for n in unbound_fresh_decls:
_, n = sexpr.unloc(n)
sym = sub_scope.enter(n)
bound_var = te.Bound(n, forall_scope)
bound_vars.append(bound_var)
tenv[sym] = te.App(types.type_type, bound_var)
return te.Forall(forall_scope, tuple(bound_vars),
module.eval(polytype))
def record(module, pairs, row):
clc = module.clc
filename = clc.filename
location = clc.location
level = tc_state.push_level()
kv = []
for each in pairs:
loc, (attr_name, expr) = sexpr.unloc(each)
expr = module.eval_with_implicit(expr)
kv.append((attr_name, expr))
kv.sort(key=lambda tp: tp[0])
elts = [elt for _, elt in kv]
left = ir.Tuple(elts)
fields = []
for k, v in kv:
v_type = tc_state.infer(v.type)
if isinstance(v_type, te.Forall):
v_type = v_type.poly_type
fields.append((k, v_type))
if not row:
mono = te.Record(te.row_from_list(fields, te.empty_row))
mono = generalise_type(tc_state,
mono,
level=level,
loc=location,
filename=filename)
return ir.Expr(expr=ir.Tuple(
[anyway(left), anyway(ir.Tuple([]))]),
type=mono)
right = module.eval_with_implicit(row)
poly = tc_state.infer(
te.Record(te.row_from_list(fields, te.RowPoly(right.type))))
poly = generalise_type(tc_state,
poly,
level=level,
loc=location,
filename=filename)
return ir.Expr(expr=ir.Merge(left=anyway(left), right=right),
type=poly)
def type(module, typename, typedef):
clc = module.clc
path = clc.path
loc, typename = sexpr.unloc(typename)
qual_typename = '{}.{}'.format(path, typename)
sym_typename = clc.scope.enter(typename)
if typedef:
# type alias
nom_type = tc_state.infer(Typing(clc).eval(typedef))
else:
nom_type = types.Nom(qual_typename,
loc=loc,
filename=clc.filename)
tenv[sym_typename] = te.App(types.type_type, nom_type)
return wrap_loc(
loc,
ignore(
ir.Set(sym_typename,
ir.Expr(type=nom_type, expr=ir.Const(nom_type)))))
def coerce(module, expr):
expr = module.eval(expr)
loc, _ = sexpr.unloc(expr)
return ir.Expr(expr=ir.Coerce(expr),
type=new_var(module.clc, "coerce"))
def module(module_eval, is_rec, name, stmts, loc=None):
loc, name = sexpr.unloc(name)
clc = module_eval.clc
scope = clc.scope
filename = clc.filename
path = clc.path = '.'.join(
(*filter(None, clc.path.split('.')), name))
# only for recursive modules.
sym_mod: typing.Optional[Sym] = None
# generated ir outside module;
# only for recursive modules.
outer_stmts: typing.List[ir.Expr] = []
# generated ir for module itself
inner_stmts: typing.List[ir.Expr] = []
# type of module. will be a non-extensible record.
type_mod = None
# recursive module.
if is_rec:
sym_mod = scope.enter(name)
new_var = tc_state.new_var(Var=types.Var,
loc=loc,
filename=filename,
name=path)
type_mod = tenv[sym_mod] = new_var
outer_stmts.append(
ignore(ir.Set(sym_mod, ignore(ir.Const(())))))
# for preprocessing
# 1. recursive functions and
# 2. type definitions.
filter_stmts = []
for stmt in stmts:
_, stmt_unloc = sexpr.unloc(stmt)
# type definition
if stmt_unloc[0] is sexpr.type_k:
inner_stmts.append(module_eval.eval(stmt))
continue
filter_stmts.append(stmt)
if stmt_unloc[0] is sexpr.def_k:
if stmt_unloc[1]:
# Recursive definition. It's guaranteed to
# be a function in syntax level.
loc, n = sexpr.unloc(stmt_unloc[2])
sym = scope.enter(n)
tenv[sym] = tc_state.new_var(Var=types.Var,
loc=loc,
filename=filename,
name=n)
for stmt in filter_stmts:
inner_stmts.append(module_eval.eval(stmt))
syms = [
sym for sym in scope.get_newest_bounds() if sym is not sym_mod
]
row_mod = te.row_from_list([(s.name, tenv[s]) for s in syms],
te.empty_row)
if type_mod:
# recursive module
tc_state.unify(type_mod, te.Record(row_mod))
else:
type_mod = te.Record(row_mod)
elts_mod = [ir.Expr(type=tenv[sym], expr=sym) for sym in syms]
elts_mod.sort(key=_sort_sym)
val_mod = ir.Expr(type=type_mod,
expr=ir.Tuple([
anyway(ir.Tuple(elts_mod)),
anyway(ir.Tuple([]))
]))
inner_stmts.append(val_mod)
exp_mod = ir.Expr(type=type_mod, expr=ir.Block(inner_stmts))
if not is_rec:
return exp_mod
outer_stmts.append(ignore(ir.Set(sym_mod, exp_mod)))
outer_stmts.append(ir.Expr(type=type_mod, expr=sym_mod))
return ir.Expr(type=type_mod, expr=ir.Block(outer_stmts))