def step(goals):
def undo():
l = len(vs) - vtop
while (l):
vs.pop()
l -= 1
while trail:
v = trail.pop()
if v < vtop: vs[v] = v
# fresh copy of term, with vars >=vtop
def relocate(t):
if isvar(t):
newt = vtop + t
if newt >= len(vs):
extendTo(newt, vs)
return newt
elif not istuple(t):
return t
else:
return tuple(map(relocate, t))
def unfold(g, gs):
for cs in css:
h, bs = cs
if not unifyWithEnv(relocate(h), g, vs, trail=trail, ocheck=False):
undo()
continue # FAILURE
else:
bs1 = relocate(bs)
bsgs = gs
for b1 in reversed(bs1) :
bsgs=(b1,bsgs)
yield bsgs # SUCCESS
# step
if goals == ():
yield extractTerm(goal, vs)
else:
trail = []
vtop = len(vs)
g, goals = goals
if db and g and g[0]=='#':
g=extractTerm(g[1:],vs)
#print(' DB_CALL:',g,'LEN0',len(trail),goals)
for ok in db.unify_with_fact(g,vs,trail):
if not ok:
#print(' FAIL', g,len(trail))
undo()
continue
#print(' BIND',extractTerm(g,vs),'-->',ok,trail,vs,goals)
yield from step(goals)
undo()
else :
for newgoals in unfold(g, goals):
yield from step(newgoals)
undo()
def unfold(l, b, gs):
g0, gs0 = gs
for cs0 in css:
newl, cs = relocate(l, cs0) # term, sorted list
h, bs0 = cs
vs = []
if not unifyWithEnv(h, g0, vs, trail=None, ocheck=True):
continue # FAILURE
else:
newb = extractTerm(b, vs)
g = extractTerm(g0, vs)
bs = fromList(bs0)
bsgs = concat(bs, gs0)
newgs = extractTerm(bsgs, vs)
r = newl, (newb, newgs)
yield r # SUCCESS
def step(g, goals):
vtop = len(vs)
def undo(vtop):
top = len(vs)
l = len(vs) - vtop
while (l):
vs.pop()
l -= 1
top = len(trail)
while trail:
v = trail.pop()
if v < vtop: vs[v] = v
def unfold(b, gs, vtop):
# fresh copy of term, with vars >=vtop
def relocate(t):
if isvar(t):
newt = vtop + t
if newt >= len(vs):
extendTo(newt, vs)
return newt
elif not istuple(t):
return t
else:
return tuple(map(relocate, t))
g0, gs0 = gs
for cs0 in css:
h0, bs0 = cs0
h = relocate(h0)
if not unifyWithEnv(h, g0, vs, trail=trail, ocheck=False):
undo(vtop)
continue # FAILURE
else:
bs1 = relocate(bs0)
bsgs = gs0
for b1 in reversed(bs1):
bsgs = (b1, bsgs)
yield bsgs # SUCCESS
trail = []
if goals == ():
yield extractTerm(g, vs)
else:
for newggs in unfold(g, goals, vtop):
goals = newggs
yield from step(g, goals)
undo(vtop)
def step(goals):
def undo():
l = len(vs) - vtop
while (l):
vs.pop()
l -= 1
while trail:
v = trail.pop()
if v < vtop: vs[v] = v
def unfold(g, gs):
# fresh copy of term, with vars >=vtop
def relocate(t):
if isvar(t):
newt = vtop + t
if newt >= len(vs):
extendTo(newt, vs)
return newt
elif not istuple(t):
return t
else:
return tuple(map(relocate, t))
for cs in css:
h, bs = cs
if not unifyWithEnv(
relocate(h), g, vs, trail=trail, ocheck=False):
undo()
continue # FAILURE
else:
bs1 = relocate(bs)
bsgs = gs
for b1 in reversed(bs1):
bsgs = (b1, bsgs)
yield bsgs # SUCCESS
# step
if goals == ():
yield extractTerm(goal, vs)
else:
trail = []
vtop = len(vs)
g, goals = goals
for newgoals in unfold(g, goals):
yield from step(newgoals)
undo()
def step(goals):
# undoes bindings of variables contained in the trail
def undo():
l = len(vs) - vtop
while (l):
vs.pop()
l -= 1
while trail:
v = trail.pop()
if v < vtop: vs[v] = v
# fresh copy of term, with vars >=vtop
def relocate(t):
if isvar(t):
newt = vtop + t
if newt >= len(vs):
extendTo(newt, vs)
return newt
elif not istuple(t):
return t
else:
return tuple(map(relocate, t))
# unfolds a goal using matching clauses
def unfold(g, gs):
for cs in css:
h, bs = cs
if not unifyWithEnv(relocate(h), g, vs, trail=trail, ocheck=False):
undo()
continue # FAILURE
else:
bs1 = relocate(bs)
bsgs = gs
for b1 in reversed(bs1) :
bsgs=(b1,bsgs)
yield bsgs # SUCCESS
# special operators
def db_call(g,goals) :
for ok in db.unify_with_fact(g, vs, trail):
if not ok: # FAILURE
undo()
continue
yield from step(goals) # SUCCESS
undo()
def python_call(g,goals):
f=eval(g[0])
f(g[1:])
# step
if goals == ():
yield extractTerm(goal, vs)
else:
trail = []
vtop = len(vs)
g, goals = goals
op=g[0]
if op in ["~","`","``","^"] :
g = extractTerm(g[1:], vs)
if op=='~': # matches against database of facts
yield from db_call(g,goals)
elif op=='`' :
python_call(g,goals)
yield from step(goals)
undo()
elif op=='^' :
yield g
yield from step(goals)
undo()
else :
for newgoals in unfold(g, goals):
yield from step(newgoals)
undo()
def step(goals):
# undoes bindings of variables contained in the trail
def undo():
l = len(vs) - vtop
while (l):
vs.pop()
l -= 1
while trail:
v = trail.pop()
if v < vtop: vs[v] = v
# fresh copy of term, with vars >=vtop
def relocate(t):
if isvar(t):
newt = vtop + t
if newt >= len(vs):
extendTo(newt, vs)
return newt
elif not istuple(t):
return t
else:
return tuple(map(relocate, t))
# unfolds a goal using matching clauses
def unfold(g, gs):
for cs in css:
h, bs = cs
if not unifyWithEnv(
relocate(h), g, vs, trail=trail, ocheck=False):
undo()
continue # FAILURE
else:
bs1 = relocate(bs)
bsgs = gs
for b1 in reversed(bs1):
bsgs = (b1, bsgs)
yield bsgs # SUCCESS
## special operators
# yields facts matching g in db
def db_call(g, goals):
for ok in db.unify_with_fact(g, vs, trail):
if not ok: # FAILURE
undo()
continue
yield from step(goals) # SUCCESS
undo()
# simple call to Python (e.g., print)
def python_call(g, goals):
f = eval(g[0])
f(*g[1:])
# unifies with last arg yield from a generator
# and first args, assumed ground, passed to it
def gen_call(g, goals):
gen = eval(g[0])
g = g[1:]
v = g[-1:]
args = g[:-1]
for r in gen(*args):
yield r
if not unifyWithEnv(v, r, vs, trail=trail, ocheck=False):
undo()
else:
yield from step(goals)
undo()
def dispatch_call(op, g, goals):
if op == '~': # matches against database of facts
yield from db_call(g, goals)
elif op == '^':
yield g
yield from step(goals)
undo()
elif op == '`':
python_call(g, goals)
yield from step(goals)
undo()
else: # ^^ generator call
yield from gen_call(g, goals)
# step
if goals == ():
yield extractTerm(goal, vs)
else:
trail = []
vtop = len(vs)
g, goals = goals
op = g[0]
if op in ["~", "`", "``", "^"]:
g = extractTerm(g[1:], vs)
yield from dispatch_call(op, g, goals)
else:
for newgoals in unfold(g, goals):
yield from step(newgoals)
undo()