def insertAppend(C6, v, e) :
"""appends e to the end of array/list v in the heap.
Does the same actions as an insertAssign to an indexed array,
but preserves more heap info since the append does not produce
any aliases within v
params : C6; v - a vartee; e - an etree
"""
sigma = C6["store"]
heap = C6["heap"]
vname = v[1]
vold = Parse.makeOldVar(v)
if lookupType(C6, vname) != "array" :
error("cannot append to a non-list/array")
else :
loc = PE.peToTuple(sigma[vname])
length = heap[loc][0]
newlength = PE.add(length, PE.make(1))
vector = heap[loc][1]
# assign original to v_old:
sigma[vold[1]] = sigma[vname]
# make copy for the new value of v:
copy = {}
for k in vector :
copy[k] = vector[k]
newloc = PE.make(PE.makeSym())
rhs = PE.evall(C6, e)
copy[ PE.peToTuple(length) ] = rhs
sigma[vname] = newloc
heap[ PE.peToTuple(newloc) ] = (newlength, copy)
def insertAssign(C6, v, etree):
"""updates the store of C6 with an assignment.
If v already exists in C6's store, saves former value as v_old
for later use in proof reasoning.
params: v - has form, ["var", s] or ["index", ["var", s], etree]
etree - another etree, to be assigned to the var.
"""
sigma = C6["store"]
heap = C6["heap"]
badvars = C6["novars"]
if v[0] == "var" : vtree = v
elif v[0] == "index" : vtree = v[1]
vold = Parse.makeOldVar(vtree) # ["var", vname_old]
# first, check if we are allowed to update v:
if (vtree in badvars) :
error("you may not update a protected global var outside of its maintenance function")
return
# if possible, rename current value of var v as v_old:
if v[0] == "var" and v[1] in sigma : # and lookupType(C6, v[1]) != "array":
sigma[vold[1]] = sigma[v[1]] # assign v's current value to v_old
elif v[0] == "index" and lookupType(C6, v[1][1]) == "array":
vname = v[1][1]
loc = PE.peToTuple(sigma[vname])
length = heap[loc][0]
vector = heap[loc][1]
# make copy:
copy = {}
for k in vector :
copy[k] = vector[k]
# assign original to v_old and copy to v :
sigma[vold[1]] = sigma[vname]
newloc = PE.make(PE.makeSym())
sigma[vname] = newloc
heap[ PE.peToTuple(newloc) ] = (length, copy)
# (later, vold will be erased from sigma....)
# now, eval assignment's rhs and store it into v:
rhs = PE.evall(C6, etree)
if v[0] == "var": # simple var
sigma[v[1]] = rhs
elif v[0] == "index": # an array/list reference
# eval index expression (NOTE: no nested indexing allowed):
indexpe = PE.evall(C6, v[2])
# save values in sigma[vname][1] provably distinct from vname[index]:
vname = v[1][1]
if vname not in sigma or lookupType(C6, vname) != "array" :
error(vname + " is not an array in the store")
#sigma[vname] = PE.makeArray()
else :
vmap = heap[PE.peToTuple(sigma[vname])][1]
saveDistinctElements(C6, vmap, indexpe)
vmap[PE.peToTuple(indexpe)] = rhs