LR法を使ったparser (某三実験用につくったもの)

LR_table.csv

parser.py

parser = ""
plist = {}
gram = {}

f = open("LR_table.csv", 'r')
c = 0
def fact(n):
    ret = 1
    for i in xrange(1,n+1):
        ret *= i
    return ret
def action(code, st, cc):
    if code=='' or code=='id':
        # none
        return
    elif code=='1':
        pass
    elif code=='10':
        arg2 = st.pop()
        arg1 = st.pop()
        st.append(arg1*10 + arg2)
    elif code=='~':
        st.append(~st.pop())
    elif code=='!':
        st.append(fact(st.pop()))
    else:
        arg2 = st.pop();
        arg1 = st.pop();
        st.append( eval(str(arg1)+code+str(arg2)) )
    return

# read parse table from csv file
for line in f:
    s = line.strip().split(',')
    if c==0:
        parser = s[1:]
    elif s[0]=='g':
        gram[int(s[1])] = [s[2], s[3], s[4]]
    elif s[0]!='':
        plist[int(s[0])] = s[1:]
    c += 1

# do parsing
dig = "0123456789"
while 1:
    ex = False
    stack = [0]
    calc = []
    ch = []
    cc = ''
    s = raw_input()+'$'
    # parse characters one by one
    for c in s:
        cc = c
        if c in dig:
            c = 'id'
        shift = -1
        print "Input ========> ",c
        # shift and reduce
        while 1:
            q = stack[-1]
            p = parser.index(c)
            mov = plist[q][p]
            #print "(%d,%s) => '%s'"%(q,c,mov)
            if mov=='':
                print "error"
                ex = True
                break
            elif mov=='acc':
                print "accept"
                ex = True
                break
            elif mov[0]=='s':
                shift = int(mov[1:])
                break
            elif mov[0] in dig:
                shift = int(mov)
                break
            elif mov[0]=='r':
                r = int(mov[1:])
                g = gram[r]
                #print "(%s -> %s)"%(g[0],g[1])
                action(g[2], calc, cc)
                arg = []
                for i in g[1]:
                    # code
                    arg.append(stack.pop());
                    stack.pop();
                qq = stack[-1]
                pp = parser.index(g[0])
                sh = plist[qq][pp]
                #print "(%d,%s) => '%s'"%(qq,g[0],sh)
                if sh=='':
                    print "error : reduce"
                    ex = True
                    break
                # code
                stack.append(g[0])
                stack.append(int(sh))
                ch.append(r)
            else:
                print "error"
                ex = True
                break
            #print "stack :", stack
            #print "calc  :", calc
        # error or accept
        if ex:
            break
        if cc in dig:
            calc.append(int(cc))
        stack.append(c)
        stack.append(shift)
        print "stack :",stack
        print "calc  :",calc
    print ch
    print "calc result :",calc