def addpairs(plst,x,alst,dLst):
try:
if alst.kind==-4:
return alst
except:
a=2
obj= SExp.SExp(3)
obj.left=car(plst)
if x.kind in [1,2]:
obj.right = x
else:
obj.right=car(x)
alst=[j for j in alst]
alst.append(obj)
if cdr(plst).getString()!='NIL' and cdr(x).getString()!='NIL':
alst=[j for j in addpairs(cdr(plst),cdr(x),alst,dLst)]
else:
if cdr(plst).getString()!='NIL' and cdr(x).getString()=='NIL':
errorObj = SExp.SExp(-4)
errorObj.string = 'parameter count less'
return errorObj
if cdr(plst).getString()=='NIL' and (x.kind==3 and cdr(x).getString()!='NIL'):
errorObj = SExp.SExp(-4)
errorObj.string = 'parameter count more'
return errorObj
return alst
def evlis (lst, alst,dLst):
if lst.kind==-4:
return lst
if isNull(lst) == 'T':
return dLst['NIL']
else:
return cons(evaluate(car(lst),alst,dLst),evlis(cdr(lst),alst,dLst))
def evconHelper(be,alst,dLst):
while(be.getString()!='NIL'):
lexp,rexpr = evcon(car(be),alst,dLst)
if lexp == 'T':
return rexpr
else:
be = cdr(be)
if be.getString() == 'NIL':
errorObj = SExp.SExp(-4)
errorObj.string = 'Invalid EVCON Expression:Catch all missing'
return errorObj
def chkParams(lst,buff):
if lst.kind == -4:
return lst
if lst.getString() == 'NIL':
return 'T'
obj = car(lst)
if(obj.getString() not in buff and not isPrimitive(obj.getString())):
buff.append(obj.getString())
return chkParams(cdr(lst), buff)
else:
return -4
def evcon(be,alst,dLst):
if be.kind == -4:
print be.getValidString()
if isNull(be) == 'T':
print dLst['NIL'].getValidString()
else:
lExp = evaluate(car(be),alst,dLst).getString()
if lExp not in ['T','NIL']:
errorObj = SExp.SExp(-4)
errorObj.string = 'Invalid EVCON Expression'
return lExp,errorObj
if lExp == 'T':
if cdr(cdr(be)).getString()!='NIL':
errorObj = SExp.SExp(-4)
errorObj.string = 'Invalid EVCON Expression:more than one expression to eval'
return lExp,errorObj
rExp = evaluate(car(cdr(be)),alst,dLst)
return lExp,rExp
else:
return lExp,''
def apply_function(f,x,alst,dLst):
if x.kind==3 and (x.left.getString()=='NIL' and x.right.getString()=='NIL'):
x=dLst['NIL']
if f.kind==-4:
return f
if x.kind == -4:
return x
if atom(f) == 'T' :
if eq(f,dLst['CAR']) == 'T' :
return car(car(x))
elif eq(f,dLst['CDR']) == 'T' :
return cdr(car(x))
elif eq(f,dLst['CONS']) == 'T' :
if(cdr(cdr(x)).getString()!='NIL'):
errorObj = SExp.SExp(-4)
errorObj.string = 'CONS takes only two atomic arguments'
return errorObj
return cons(car(x),car(cdr(x)))
elif eq(f,dLst['ATOM']) == 'T' :
if(cdr(x).getString()=='NIL'):
return dLst[atom(car(x))]
return dLst[atom(x)]
elif eq(f,dLst['INT']) == 'T' :
if(cdr(x).getString()=='NIL'):
return dLst[isInt(car(x))]
return dLst[atom(x)]
elif eq(f,dLst['NULL']) == 'T' :
return dLst[isNull(x)]
elif eq(f,dLst['PLUS']) == 'T' :
if(cdr(cdr(x)).getString()!='NIL' or car(x).kind!=1 or car(cdr(x)).kind!=1):
errorObj = SExp.SExp(-4)
errorObj.string = 'PLUS takes only two integer arguments'
return errorObj
obj=plus(car(x),car(cdr(x)))
if(obj.kind==-4):
return obj
if(obj.value not in dLst.keys()):
dLst[obj.value]=obj
setDict(dLst)
return obj
elif eq(f,dLst['MINUS']) == 'T' :
if(cdr(cdr(x)).getString()!='NIL' or car(x).kind!=1 or car(cdr(x)).kind!=1):
errorObj = SExp.SExp(-4)
errorObj.string = 'MINUS takes only two integer arguments'
return errorObj
obj=minus(car(x),car(cdr(x)))
if(obj.value not in dLst.keys()):
dLst[obj.value]=obj
setDict(dLst)
return obj
elif eq(f,dLst['TIMES']) == 'T' :
if(cdr(cdr(x)).getString()!='NIL' or car(x).kind!=1 or car(cdr(x)).kind!=1):
errorObj = SExp.SExp(-4)
errorObj.string = 'TIMES takes only two integer arguments'
return errorObj
obj=times(car(x),car(cdr(x)))
if(obj.value not in dLst.keys()):
dLst[obj.value]=obj
setDict(dLst)
return obj
elif eq(f,dLst['QUOTIENT']) == 'T' :
if(cdr(cdr(x)).getString()!='NIL' or car(x).kind!=1 or car(cdr(x)).kind!=1):
errorObj = SExp.SExp(-4)
errorObj.string = 'QUOTIENT takes only two integer arguments'
return errorObj
obj=divide(car(x),car(cdr(x)))
if(obj.value not in dLst.keys()):
dLst[obj.value]=obj
setDict(dLst)
return obj
elif eq(f,dLst['REMAINDER']) == 'T' :
if(cdr(cdr(x)).getString()!='NIL' or car(x).kind!=1 or car(cdr(x)).kind!=1):
errorObj = SExp.SExp(-4)
errorObj.string = 'REMAINDER takes only two integer arguments'
return errorObj
obj=mod(car(x),car(cdr(x)))
if(obj.value not in dLst.keys()):
dLst[obj.value]=obj
setDict(dLst)
return obj
elif eq(f,dLst['LESS']) == 'T' :
if(cdr(cdr(x)).getString()!='NIL' or car(x).kind!=1 or car(cdr(x)).kind!=1):
errorObj = SExp.SExp(-4)
errorObj.string = 'LESS takes only two integer arguments'
return errorObj
return dLst[lt(car(x),car(cdr(x)))]
elif eq(f,dLst['GREATER']) == 'T' :
if(cdr(cdr(x)).getString()!='NIL' or car(x).kind!=1 or car(cdr(x)).kind!=1):
errorObj = SExp.SExp(-4)
errorObj.string = 'GREATER takes only two integer arguments'
return errorObj
return dLst[gt(car(x),car(cdr(x)))]
elif eq(f,dLst['EQ']) == 'T' :
if(cdr(cdr(x)).getString()!='NIL'):
errorObj = SExp.SExp(-4)
errorObj.string = 'EQ takes only two atomic arguments'
return errorObj
res=eq(car(x),car(cdr(x)))
if res == 'T' or res=='NIL':
return dLst[res]
else:
return res
else:
try:
tlst = getDefLst()
if f.getString() not in tlst.keys():
errorObj = SExp.SExp(-4)
errorObj.string = 'Undefined function:'+f.getString()
return errorObj
fundef = tlst[f.getString()]
setDefun(True)
return evaluate(car(cdr(fundef)),addpairs(car(fundef),x,alst,dLst),dLst)
except:
errorObj = SExp.SExp(-4)
errorObj.string = 'Improper input for function or function execution did not complete'
return errorObj
def evaluate(exp, alst,dLst):
if(exp.kind==-4):
return exp
if atom(exp) == 'T':
if isInt(exp) == 'T':
return exp
elif eq(exp,dLst['T']) == 'T':
return dLst['T']
elif eq(exp,dLst['NIL']) == 'T':
return dLst['NIL']
elif getMapping(exp.getString(),alst,False).kind!=-4:
return getMapping(exp.getString(),alst,True)
else:
errorObj = SExp.SExp(-4)
errorObj.string = 'Unbound Variable'
return errorObj
elif atom(car(exp))=='T':
if eq(car(exp),dLst['QUOTE']) == 'T':
if cdr(exp).right.getString() == 'NIL':
return car(cdr(exp))
else:
errorObj = SExp.SExp(-4)
errorObj.string = 'Too Many Args for QUOTE'
return errorObj
elif eq(car(exp),dLst['COND']) == 'T':
return evconHelper(cdr(exp),alst,dLst)
elif eq(car(exp),dLst['DEFUN']) == 'T':
key = car(cdr(exp))
if cdr(cdr(cdr(cdr(exp)))).getString()!='NIL':
errorObj = SExp.SExp(-4)
errorObj.string = 'Invalid Defun syntax'
return errorObj
if isPrimitive(key.getString()) :
errorObj = SExp.SExp(-4)
errorObj.string = 'Cannot replace primitives'
return errorObj
temp = cdr(exp)
val=cdr(temp)
res = chkParams(car(val),[])
if res == 'T':
tlst = getDefLst()
splt = val.getString().replace('(', ' ( ').replace(')',' ) ').replace('.',' . ').split()
if 'DEFUN' in splt:
errorObj = SExp.SExp(-4)
errorObj.string = 'Cannot Define function inside a UDF'
return errorObj
tlst[key.getString()]=val
setDefLst(tlst)
return key
else:
if res == -4:
errorObj = SExp.SExp(-4)
errorObj.string = 'Parameter Names Should Be Unique and non primitives'
return errorObj
return res
else:
return apply_function(car(exp),evlis(cdr(exp),alst,dLst),alst,dLst)
else:
errorObj = SExp.SExp(-4)
errorObj.string = 'Invalid Eval Expression'
return errorObj