def modify_psyir_tree():
''' Apply modifications to the PSyIR tree created in create.py
:returns: a modified PSyIR tree.
:rtype: :py:class:`psyclone.psyir.nodes.Container`
'''
file_container = create_psyir_tree()
container = file_container.children[0]
subroutine = container.children[0]
# Rename one of the subroutine local symbols.
tmp_symbol = subroutine.symbol_table.lookup("psyir_tmp")
subroutine.symbol_table.rename_symbol(tmp_symbol, "new_variable")
# The type of a symbol might be unknown
symbol = Symbol("unused")
container.symbol_table.add(symbol)
# later its type could be determined. However, we don't want to
# replace the existing symbol instance with a new instance as it
# may have references, which could then lead to inconsistencies. Therefore
# we support the specialise method, which transforms the existing
# node type to a subclass of type without changing the memory
# location of the instance. Note, any additional subclass properties would
# have to be added manually.
symbol.specialise(RoutineSymbol)
# In some cases we may want to replace one node with another. This
# can be simply done using a node's replace_with method.
assignment = subroutine.children[2]
assignment_rhs = assignment.rhs
assignment_rhs.replace_with(Reference(tmp_symbol))
return file_container
def test_symbol_specialise():
'''Test the Symbol.specialise() method.'''
# pylint: disable = unidiomatic-typecheck
asym = Symbol("a")
assert type(asym) is Symbol
assert str(asym) == "a"
asym.specialise(RoutineSymbol)
assert type(asym) is RoutineSymbol
assert str(asym) == "a : RoutineSymbol"
