def construct_operand(op):
from langkit.expressions import Cast, New
expr = construct(op)
check_source_language(
expr.type == LogicVarType
or expr.type.matches(T.root_node)
or expr.type.matches(T.root_node.env_el()),
"Operands to a logic bind operator should be either "
"a logic variable or an ASTNode, got {}".format(expr.type)
)
if expr.type.matches(T.root_node.env_el()):
if expr.type is not T.root_node.env_el():
expr = Cast.Expr(expr, T.root_node.env_el())
elif expr.type.matches(T.root_node):
# Cast the ast node type if necessary
if expr.type is not T.root_node:
expr = Cast.Expr(expr, T.root_node)
# If the expression is a root node, implicitly construct an
# env_element from it.
expr = New.StructExpr(T.root_node.env_el(), {
Name('El'): expr,
Name('MD'): LiteralExpr('<>', None),
Name('Parents_Bindings'): LiteralExpr('null', None)
})
return expr
def make_as_entity(node_expr,
entity_info=None,
null_check=True,
abstract_expr=None):
"""
Helper for as_entity. Takes a resolved expression instead of an abstract
one.
:param ResolvedExpression node_expr: The AST node expression to wrap as an
entity.
:param ResolvedExpression|None entity_info: Expression to use as the entity
information. If provided, its type must be T.entity_info. Otherwise,
the ambient entity info is used.
"""
from langkit.expressions import If, IsNull, New
entity_type = node_expr.type.entity
# If we use the ambient entity info, make the current property an entity
# one.
if entity_info is None:
p = PropertyDef.get()
p.set_uses_entity_info()
entity_info = construct(p.entity_info_arg)
# Expression tree sharing is forbidden, so if we need to reference the
# result of the input node expression multiple times, create a variable to
# hold the input node.
node_ref = (node_expr.create_result_var('Node_For_Entity')
if null_check else node_expr)
entity_expr = New.StructExpr(
entity_type,
{
names.Name('El'): node_ref,
names.Name('Info'): entity_info
},
result_var_name=names.Name.from_lower('as_entity'),
)
result = If.Expr(
IsNull.construct_static(node_expr),
NullExpr(entity_type),
entity_expr,
entity_type,
abstract_expr=abstract_expr) if null_check else entity_expr
result.abstract_expr = abstract_expr
return result
