def number(self, n):
"Generates Number Expression"
lf = let.Abstraction(expr=None)
lx = let.Abstraction(expr=None)
x = let.Variable(lx)
for _ in range(n):
f = let.Variable(lf)
x = let.Application(func=f, arg=x)
lx.expr = x
lf.expr = lx
return lf
def delete(node):
if let.ABS == node.type:
# Reref Abs-Vars to 0
node.replace({node: 0})
# Remove from Tree
node.subst(node.expr)
elif let.LET == node.type:
pass # ?? Can't delete
else: # APPL or VAR
parent = node.parent
if let.ABS == parent.type:
if let.VAR == node.type: # VAR - Can't delete
node.ref = 0
else: # APPL - Replace to VAR
var = let.Variable()
var.ref = 0
node.subst(var)
elif let.APPL == parent.type:
if node == parent.func:
parent.subst(parent.arg)
elif node == parent.arg:
parent.subst(parent.func)
def eventAddVariable(self):
fig = Figure(let.Variable())
# Set position to center of view
v = self.centerOfView()
fig.position.setTranspose(v[0], v[1], 1)
fig.refreshTransform()
self.items.insert(0, fig)
self.invalidate()
def applicationAfter(node):
debug('con', 'add application after', node)
var = let.Variable()
var.ref = 0 # Free Variable
appl = let.Application(func=None, arg=var)
node.subst(appl)
appl.func = node
def applicationBefore(node):
debug('con', 'add application before', node)
var = let.Variable()
var.ref = 0 # Free Variable
appl = let.Application(func=var, arg=None)
node.subst(appl)
appl.arg = node