def do_prepare(self):
argspec = inspect.getargspec(self.expr_fn)
check_multiple([
(len(argspec.args)
in (1, 2), 'Invalid collection iteration lambda: only one '
'or two parameters expected'),
(not argspec.varargs and not argspec.keywords,
'Invalid collection iteration lambda: no *args or **kwargs'),
(not argspec.defaults,
'Invalid collection iteration lambda: No default values allowed '
'for arguments')
])
self.requires_index = len(argspec.args) == 2
self.element_var = AbstractVariable(
names.Name("Item_{}".format(next(CollectionExpression._counter))),
source_name=names.Name.from_lower(argspec.args[0]))
if self.requires_index:
self.index_var = AbstractVariable(
names.Name('I'),
type=LongType,
create_local=True,
source_name=names.Name.from_lower(argspec.args[1]))
expr = self.expr_fn(self.index_var, self.element_var)
else:
expr = self.expr_fn(self.element_var)
self.expr = unsugar(expr)
def do_prepare(self):
# When this expression does not come from our Python DSL (see the
# initialize method above), the sub-expression is ready to use: do not
# try to expand the function.
if self.expr is not None:
return
argspec = inspect.getargspec(self.expr_fn)
check_multiple([
(len(argspec.args) in (1, 2),
'Invalid collection iteration lambda: only one '
'or two parameters expected'),
(not argspec.varargs and not argspec.keywords,
'Invalid collection iteration lambda: no *args or **kwargs'),
(not argspec.defaults,
'Invalid collection iteration lambda: No default values allowed '
'for arguments')
])
if len(argspec.args) == 2:
self.requires_index = True
index_var_pos = 0
item_var_pos = 1
else:
self.requires_index = False
index_var_pos = None
item_var_pos = 0
# Get the name of the loop variable from the DSL. But don't when we
# have a "default" one, such as for using the ".filter" combinator. In
# this case, it's up to ".filter"'s special implementation to get the
# name from the filter function.
source_name = (None if self.expr_fn == collection_expr_identity else
names.Name.from_lower(argspec.args[item_var_pos]))
self.element_var = AbstractVariable(
names.Name("Item_{}".format(next(CollectionExpression._counter))),
source_name=source_name
)
if self.requires_index:
self.index_var = AbstractVariable(
names.Name('I'), type=T.Int,
source_name=names.Name.from_lower(argspec.args[index_var_pos])
)
expr = self.expr_fn(self.index_var, self.element_var)
else:
expr = self.expr_fn(self.element_var)
self.expr = unsugar(expr)
def create_iteration_var(
self,
existing_var: Optional[AbstractVariable],
name_prefix: str,
source_name: Optional[str] = None,
type: Optional[CompiledType] = None
) -> AbstractVariable:
"""
Create (when needed) an iteration variable and assign it (when
provided) a source name.
:param existing_var: Existing iteration variable. If provided, do not
create a new variable.
:param name_prefix: Prefix for the name of this variable in the
generated code.
:param source_name: If available, name of this variable in the DSL.
:param type: Type for the variable.
"""
if existing_var is None:
result = AbstractVariable(
names.Name(f"{name_prefix}_{next(self._counter)}"),
type=type,
)
else:
assert type == existing_var.type, (
f"Inconsistent type for {existing_var}: {type} and"
f" {existing_var.type}"
)
result = existing_var
if result.source_name is None and source_name is not None:
result.source_name = source_name
return result
def do_prepare(self):
self.matchers = []
for i, match_fn in enumerate(self.matchers_functions):
argspec = inspect.getargspec(match_fn)
check_source_language(
len(argspec.args) == 1 and
not argspec.varargs and
not argspec.keywords and
(not argspec.defaults or len(argspec.defaults) < 2),
'Invalid matcher lambda'
)
if argspec.defaults:
match_type = resolve_type(argspec.defaults[0])
check_source_language(
issubclass(match_type, T.root_node)
or match_type.is_env_element_type,
'Invalid matching type: {}'.format(
match_type.name().camel
)
)
else:
match_type = None
match_var = AbstractVariable(
names.Name('Match_{}'.format(i)),
type=match_type,
create_local=True,
source_name=names.Name.from_lower(argspec.args[0])
)
self.matchers.append((match_type, match_var, match_fn(match_var)))
def construct_common(self):
"""
Construct the expressions commonly needed by collection expression
subclasses, and return them as a tuple constituted of:
1. The resolved collection expression.
2. The resolved expression function passed to CollectionExpression's
constructor.
3. If the collection is an AST list, the iteration variable, whose type
is the root grammar type. None otherwise.
4. The element variable as a resolved expression. In the case of an AST
list collection, this is just 3. converted to the specific type.
5. The index variable as a resolved expression.
6. The inner scope for the iteration.
:rtype: (ResolvedExpression,
ResolvedExpression,
ResolvedExpression|None,
ResolvedExpression,
ResolvedExpression,
langkit.expressions.base.LocalVars.Scope)
"""
collection_expr = construct(
self.collection, lambda t: t.is_collection(),
'Map cannot iterate on {expr_type}, which is not a collection')
self.element_var.set_type(collection_expr.type.element_type())
current_scope = PropertyDef.get_scope()
# If we are iterating over an AST list, then we get root grammar typed
# values. We need to convert them to the more specific type to get the
# rest of the expression machinery work. For this, create a new
# variable.
if collection_expr.type.is_list_type:
self.list_element_var = AbstractVariable(
names.Name("List_Item_{}".format(
next(CollectionExpression._counter))),
type=get_context().root_grammar_class)
self.element_var.add_to_scope(current_scope)
with current_scope.new_child() as iter_scope:
if self.index_var:
PropertyDef.get_scope().add(self.index_var.local_var)
return (collection_expr, construct(self.expr), (construct(
self.list_element_var) if self.list_element_var else None),
construct(self.element_var),
construct(self.index_var) if self.index_var else None,
iter_scope)
def do_prepare(self):
# If this Then was created using create_from exprs, there is no lambda
# expansion to do.
if self.then_expr:
return
argspec = inspect.getargspec(self.then_fn)
check_source_language(
len(argspec.args) == 1 and not argspec.varargs
and not argspec.keywords and not argspec.defaults,
'Invalid lambda for Then expression: exactly one parameter is'
' required, without a default value')
self.var_expr = AbstractVariable(names.Name("Var_Expr"),
create_local=True,
source_name=names.Name(
argspec.args[0]))
self.then_expr = unsugar(self.then_fn(self.var_expr))
def construct_common(self):
"""
Construct and return the expressions commonly needed by collection
expression subclasses.
:rtype: CollectionExpression.ConstructCommonResult
"""
current_scope = PropertyDef.get_scope()
# First, build the collection expression. From the result, we can
# deduce the type of the element variable.
collection_expr = construct(self.collection)
with_entities = collection_expr.type.is_entity_type
if with_entities:
saved_entity_coll_expr, collection_expr, entity_info = (
collection_expr.destructure_entity())
collection_expr = SequenceExpr(saved_entity_coll_expr,
collection_expr)
check_source_language(
collection_expr.type.is_collection,
'Cannot iterate on {}, which is not a collection'.format(
collection_expr.type.dsl_name))
elt_type = collection_expr.type.element_type
if with_entities:
elt_type = elt_type.entity
self.element_var.set_type(elt_type)
# List of "element" iteration variables
elt_vars = [construct(self.element_var)]
# List of initializing expressions for them
elt_var_inits = []
if with_entities:
entity_var = elt_vars[-1]
node_var = AbstractVariable(names.Name('Bare') +
self.element_var._name,
type=elt_type.element_type)
elt_var_inits.append(
make_as_entity(construct(node_var), entity_info=entity_info))
elt_vars.append(construct(node_var))
# If we are iterating over an AST list, then we get root grammar typed
# values. We need to convert them to the more specific type to get the
# rest of the expression machinery work.
if collection_expr.type.is_list_type:
typed_elt_var = elt_vars[-1]
untyped_elt_var = AbstractVariable(
names.Name('Untyped') + self.element_var._name,
type=get_context().root_grammar_class)
# Initialize the former last variable with a cast from the new last
# variable and push the new last variable.
elt_var_inits.append(
UncheckedCastExpr(construct(untyped_elt_var),
typed_elt_var.type))
elt_vars.append(construct(untyped_elt_var))
# Only then we can build the inner expression
with current_scope.new_child() as inner_scope:
inner_expr = construct(self.expr)
if with_entities:
entity_var.abstract_var.create_local_variable(inner_scope)
if collection_expr.type.is_list_type:
typed_elt_var.abstract_var.create_local_variable(inner_scope)
if self.index_var:
self.index_var.add_to_scope(inner_scope)
elt_var_inits.append(None)
return self.ConstructCommonResult(
collection_expr, funcy.lzip(elt_vars, elt_var_inits),
construct(self.index_var) if self.index_var else None, inner_expr,
inner_scope)
def construct_common(self) -> CollectionExpression.ConstructCommonResult:
"""
Construct and return the expressions commonly needed by collection
expression subclasses.
"""
assert self.element_var is not None
current_scope = PropertyDef.get_scope()
# Because of the discrepancy between the storage type in list nodes
# (always root nodes) and the element type that user code deals with
# (non-root list elements and/or entities), we may need to introduce
# variables and initializing expressions. This is what the code below
# does.
# First, build the collection expression. From the result, we can
# deduce the type of the user element variable.
collection_expr = construct(self.collection)
# If the collection is actually an entity, unwrap the bare list node
# and save the entity info for later.
with_entities = collection_expr.type.is_entity_type
if with_entities:
saved_entity_coll_expr, collection_expr, entity_info = (
collection_expr.destructure_entity()
)
collection_expr = SequenceExpr(saved_entity_coll_expr,
collection_expr)
check_source_language(
collection_expr.type.is_collection,
'Cannot iterate on {}, which is not a collection'.format(
collection_expr.type.dsl_name
)
)
# Now that potential entity types are unwrapped, we can look for its
# element type.
elt_type = collection_expr.type.element_type
if with_entities:
elt_type = elt_type.entity
self.element_var.set_type(elt_type)
user_element_var = construct(self.element_var)
# List of element variables, and the associated initialization
# expressions (when applicable).
#
# Start with the only element variable that exists at this point: the
# one that the user code for each iteration uses directly. When
# relevant, each step in the code below creates a new variable N and
# initialize variable N-1 from it.
element_vars: List[InitializedVar] = [InitializedVar(user_element_var)]
# Node lists contain bare nodes: if the user code deals with entities,
# create a variable to hold a bare node and initialize the user
# variable using it.
if with_entities:
entity_var = element_vars[-1]
node_var = AbstractVariable(
names.Name('Bare') + self.element_var._name,
type=elt_type.element_type
)
entity_var.init_expr = make_as_entity(
construct(node_var), entity_info=entity_info
)
element_vars.append(InitializedVar(construct(node_var)))
# Node lists contain root nodes: if the user code deals with non-root
# nodes, create a variable to hold the root bare node and initialize
# the non-root node using it.
if (
collection_expr.type.is_list_type
and not collection_expr.type.is_root_node
):
typed_elt_var = element_vars[-1]
untyped_elt_var = AbstractVariable(
names.Name('Untyped') + self.element_var._name,
type=get_context().root_grammar_class
)
typed_elt_var.init_expr = UncheckedCastExpr(
construct(untyped_elt_var), typed_elt_var.var.type
)
element_vars.append(InitializedVar(construct(untyped_elt_var)))
# Keep track of the ultimate "codegen" element variable. Unlike all
# other iteration variable, it is the only one that will be defined by
# the "for" loop in Ada (the other ones must be declared as regular
# local variables).
codegen_element_var = element_vars[-1].var
# Create a scope to contain the code that runs during an iteration and
# lower the iteration expression.
with current_scope.new_child() as inner_scope:
inner_expr = construct(self.expr)
# Build the list of all iteration variables
iter_vars = list(element_vars)
index_var = None
if self.index_var:
index_var = construct(self.index_var)
iter_vars.append(InitializedVar(index_var))
# Create local variables for all iteration variables that need it
for v in iter_vars:
if v.var != codegen_element_var:
v.var.abstract_var.create_local_variable(inner_scope)
return self.ConstructCommonResult(
collection_expr,
codegen_element_var,
user_element_var,
index_var,
iter_vars,
inner_expr,
inner_scope,
)
check_source_language(
p._uses_entity_info is not False,
'This property has been explicitly tagged as not using entity info, so'
' .as_entity is invalid here')
# We want to keep original type of node, so no downcast
node_expr = construct(node, T.root_node, downcast=False)
ret = make_as_entity(node_expr, abstract_expr=self)
ret.create_result_var('Ent')
return ret
@auto_attr
def as_bare_entity(self, node):
"""
Wrap `node` into an entity, using default entity information (in
particular, no rebindings).
"""
node_expr = construct(node, T.root_node, downcast=False)
ret = make_as_entity(node_expr,
entity_info=NullExpr(T.entity_info),
abstract_expr=self)
ret.create_result_var('Ent')
return ret
EmptyEnv = AbstractVariable(names.Name("AST_Envs.Empty_Env"),
type=T.LexicalEnv)
def construct(self):
"""
Construct a resolved expression for this.
:rtype: ResolvedExpression
"""
# Add the variables created for this expression to the current scope
scope = PropertyDef.get_scope()
for _, var, _ in self.matchers:
scope.add(var.local_var)
matched_expr = construct(self.matched_expr)
check_source_language(issubclass(matched_expr.type, ASTNode)
or matched_expr.type.is_env_element_type,
'Match expressions can only work on AST nodes '
'or env elements')
# Create a local variable so that in the generated code, we don't have
# to re-compute the prefix for each type check.
matched_abstract_var = AbstractVariable(
names.Name('Match_Prefix'),
type=matched_expr.type,
create_local=True
)
PropertyDef.get_scope().add(matched_abstract_var.local_var)
matched_var = construct(matched_abstract_var)
constructed_matchers = []
# Check (i.e. raise an error if no true) the set of matchers is valid:
# * all matchers must target allowed types, i.e. input type subclasses;
for typ, var, expr in self.matchers:
if typ is not None:
check_source_language(
typ.matches(matched_expr.type),
'Cannot match {} (input type is {})'.format(
typ.name().camel,
matched_expr.type.name().camel
)
)
else:
# The default matcher (if any) matches the most general type,
# which is the input type.
var.set_type(matched_expr.type)
constructed_matchers.append((construct(var), construct(expr)))
# * all possible input types must have at least one matcher. Also warn
# if some matchers are unreachable.
self._check_match_coverage(matched_expr.type)
# Compute the return type as the unification of all branches
_, expr = constructed_matchers[-1]
rtype = expr.type
for _, expr in constructed_matchers:
check_source_language(
expr.type.matches(rtype), "Wrong type for match result"
" expression: got {} but expected {} or sub/supertype".format(
expr.type.name().camel, rtype.name().camel
)
)
rtype = expr.type.unify(rtype)
# This is the expression execution will reach if we have a bug in our
# code (i.e. if matchers did not cover all cases).
result = UnreachableExpr(rtype)
# Wrap this "failing" expression with all the cases to match in the
# appropriate order, so that in the end the first matchers are tested
# first.
for match_var, expr in reversed(constructed_matchers):
casted = Cast.Expr(matched_var,
match_var.type,
result_var=match_var)
guard = Not.make_expr(
Eq.make_expr(
casted, LiteralExpr(casted.type.nullexpr(), casted.type)
)
)
if expr.type != rtype:
# We already checked that type matches, so only way this is
# true is if expr.type is an ASTNode type derived from
# rtype. In that case, we need an explicity upcast.
expr = Cast.Expr(expr, rtype)
result = If.Expr(guard, expr, result, rtype)
return Let.Expr(
[matched_var],
[matched_expr],
BindingScope(result,
[construct(var) for _, var, _ in self.matchers])
)
from langkit import names
from langkit.compiled_types import AnalysisUnitKind, AnalysisUnitType, T
from langkit.diagnostics import check_source_language
from langkit.expressions.base import (AbstractVariable, FieldAccessExpr,
PropertyDef, ResolvedExpression,
auto_attr, construct, render)
UnitSpecification = AbstractVariable(names.Name('Unit_Specification'),
type=AnalysisUnitKind)
UnitBody = AbstractVariable(names.Name('Unit_Body'), type=AnalysisUnitKind)
class AnalysisUnitRoot(ResolvedExpression):
"""
Construct that takes an analysis unit and that returns its root node.
"""
def __init__(self, unit_expr):
super(AnalysisUnitRoot, self).__init__()
self.static_type = T.root_node
self.unit_expr = unit_expr
self.prefix_var = PropertyDef.get().vars.create(
'Unit', self.unit_expr.type)
def _render_pre(self):
from langkit.compile_context import get_context
return '{}\n{}'.format(
self.unit_expr.render_pre(),
render('properties/null_safety_check_ada',
expr=self.unit_expr,
result_var=self.prefix_var)
