This is a continuation of my last question. I want to parse an equation and work on the ast I get. What I want to do is basically randomly scramble it so I get a new equation, that has to be also a valid function. This is to be used in a genetic algorithm.
Here is where I start:
class Py2do(ast.NodeTransformer):
def __init__(self):
self.tree=[]
def generic_visit(self, node):
print type(node).__name__
self.tree.append(type(node).__name__)
ast.NodeVisitor.generic_visit(self, node)
depth=3
s = node.__dict__.items()
s = " ".join("%s %r" % x for x in sorted(node.__dict__.items()))
print( "%s%s\t%s" % (depth, str(type(node)), s) )
for x in ast.iter_child_nodes(node):
print (x, depth)
def visit_Name(self, node):
# print 'Name :', node.id
pass
def visit_Num(self, node):
print 'Num :', node.__dict__['n']
def visit_Str(self, node):
print "Str :", node.s
def visit_Print(self, node):
print "Print :"
ast.NodeVisitor.generic_visit(self, node)
def visit_Assign(self, node):
print "Assign :"
ast.NodeVisitor.generic_visit(self, node)
def visit_Expr(self, node):
print "Expr :"
ast.NodeVisitor.generic_visit(self, node)
if __name__ == '__main__':
node = ast.parse("res= e**(((-0.5*one)*((delta_w*one/delta*one)**2)))")
import ast_pretty
print ast.dump(node)
pprintAst(node)
v = Py2do()
v.visit(node)
print v.tree
What I want to get out is something like this :
res= e**(delta*((one/delta_w*one)**2)))
or another valid random equation of some sort. This will be used in a Fortran program, so it would be nice if the resulting equation can also be transferred into Fortran. Please comment your code and provide a test sample/unit test.