def sub_values(tree, var_values):
"""Substitute given values for variables.
@param tree: AST
@type var_values: C{dict}
@return: AST with L{Var} nodes replaces by
L{Num}, L{Const}, or L{Bool}
"""
old2new = dict()
for u in tree.nodes_iter():
if u.type != 'var':
continue
val = var_values[u.value]
# instantiate appropriate value type
if isinstance(val, bool):
v = nodes.Bool(val)
elif isinstance(val, int):
v = nodes.Num(val)
elif isinstance(val, str):
v = nodes.Str(val)
old2new[u] = v
# replace variable by value
nx.relabel_nodes(tree, old2new, copy=False)
def tree_from_recursive_ast_test():
# (1 - x) + y
x = nodes.Var('x')
one = nodes.Num('1')
minus = nodes.Operator('-', one, x)
y = nodes.Var('y')
plus = nodes.Operator('+', minus, y)
# convert to Tree
g = tx.Tree.from_recursive_ast(plus)
assert len(g) == 5
assert set(g.nodes()) == set([x, one, minus, y, plus])
assert g.has_edge(plus, y)
assert g.has_edge(plus, minus)
assert g.has_edge(minus, one)
assert g.has_edge(minus, x)
def tree_to_recursive_ast_test():
g = tx.Tree()
x = nodes.Var('x')
one = nodes.Num('1')
minus = nodes.Operator('-', one, x)
y = nodes.Var('y')
# (1 - x) + y
plus = nodes.Operator('+', minus, y)
g.add_nodes_from([plus, x, y, one, minus])
# g is different than forula:
# x - (z + 1)
z = nodes.Var('z')
g.root = minus
g.add_edge(minus, x, key=0)
g.add_edge(minus, plus, key=1)
g.add_edge(plus, z, key=0)
g.add_edge(plus, one, key=1)
t = g.to_recursive_ast()
# -
assert isinstance(t, nodes.Operator)
assert t.operator == '-'
# must be a new object
assert t is not minus
assert len(t.operands) == 2
# x
u = t.operands[0]
assert isinstance(u, nodes.Var)
assert u.value == 'x'
assert u is not x
# +
u = t.operands[1]
assert isinstance(u, nodes.Operator)
assert u.operator == '+'
assert u is not plus
assert len(u.operands) == 2
# z
v = u.operands[0]
assert isinstance(v, nodes.Var)
assert v.value == 'z'
assert v is not z
# 1
u = u.operands[1]
assert isinstance(u, nodes.Num)
assert u.value == '1'
assert u is not one
def sub_constants(tree, var_str2int):
"""Replace string constants by integers.
To be used for converting arbitrary finite domains
to integer domains prior to calling gr1c.
@param const2int: {'varname':['const_val0', ...], ...}
@type const2int: C{dict} of C{list}
"""
# logger.info('substitute ints for constants in:\n\t' + str(self))
old2new = dict()
for u in tree.nodes_iter():
if u.type != 'str':
continue
var, op = pair_node_to_var(tree, u)
# now: c, is the operator and: v, the variable
str2int = var_str2int[str(var)]
x = str2int.index(u.value)
num = nodes.Num(str(x))
# replace Const with Num
old2new[u] = num
nx.relabel_nodes(tree, old2new, copy=False)