模板参数解析

input: A, A2, C2>, A3<>, A4< B4<>, C4>>
output:
A< B, C >
B2< C, D >
C2< D >
A2< B2< C, D >, C2< D > >
A3<  >
B4<  >
D4< E4 >
C4< D4< E4 > >
A4< B4<  >, C4< D4< E4 > > >

python code:

#!/usr/bin/env python

class Template(object):
    def __init__(self):
        self.name = ""
        self.args = []

    def __str__(self):
        return self.name + "< " + ", ".join([str(a) for a in self.args]) + " >"
    __repr__ = __str__

def parse_template(ts):
    tlist = []
    stk = []
    pos = 0
    arg = ""

    for i, c in enumerate(ts):
        if c in "<>,":
            if c == '<':
                t = Template()
                t.name = ts[pos : i].strip()
                stk.append(t)
            elif c == '>':
                t = stk.pop()
                arg = ts[pos : i].strip()
                if arg:
                    t.args.append(arg)
                if stk:
                    stk[-1].args.append(t)
                #else:
                tlist.append(t)
            else: # comma
                arg = ts[pos : i].strip()
                if arg and stk:
                    stk[-1].args.append(arg)
            pos = i + 1
    return tlist


ts = input("input:")
tlist = parse_template(ts)
for t in tlist:
    print(str(t))

C++ code:

#include <stdio.h>
#include <stdlib.h>
#include <string>
#include <stack>
#include <iostream>

using namespace std;

struct Temp
{
    size_t name;
    size_t start;
    size_t end;
};

void print_temp(const string& temp)
{
    stack<Temp> st;
    size_t pos1 = 0;
    size_t pos2 = 0;

    while (pos1 < temp.size())
    {
        pos2 = temp.find_first_of("<,>", pos1);
        if (pos2 == string::npos)
        {
            break;
        }

        if (temp.at(pos2) == '<')
        {
            Temp t;
            t.name = pos1;
            t.start = pos2;
            t.end = string::npos;
            st.push(t);
        }
        else if (temp.at(pos2) == '>')
        {
            if (st.empty())
            {
                // error
                cout << "unmatched angle brackets" << endl;
                break;
            }
            else
            {
                st.top().end = pos2;
                Temp t = st.top();
                st.pop();
                cout << "name: " << temp.substr(t.name, t.start - t.name) << endl;
                cout << "arg: " << temp.substr(t.start + 1, pos2 - t.start - 1) << endl;
            }
        }
        else
        {
            // comma
        }

        pos1 = pos2 + 1;
    }

    if (!st.empty())
    {
        cout << "unmatched angle brackets" << endl;
    }
}

int main(int argc, char **argv)
{
    char lbuf[1024];
    cin.getline(lbuf, sizeof(lbuf));
    print_temp(lbuf);

    return 0;
}