interpreter.cpp

#include <cstdlib>
#include <string>
#include <vector>

struct ast{
    std::vector<ast*> sub;
    std::string token;
    std::string type;
};

void interpreter(const std::string code){
    std::vector<std::vector<ast*>> stack;
    ast *ptr = nullptr;
    for(std::size_t i = 0; i < code.size(); ++i){
        char c = code[i];
        if(c >= 'a' && c <= 'z' || c >= 'A' && c <= 'Z'){
            if(!ptr){ stack.back().push_back(ptr = new ast); ptr->type = "token"; }
            ptr->token.push_back(c);
        }else if(c >= '0' && c <= '9'){
            if(!ptr){ stack.back().push_back(ptr = new ast); ptr->type = "value"; }
            ptr->token.push_back(c);
        }else if(c == '\''){
            stack.resize(stack.size() + 1);
            stack.back().push_back(ptr = new ast);
            ptr->type = "ast";
            ptr = nullptr;
        }else if(c == '('){
            stack.resize(stack.size() + 1);
            stack.back().push_back(ptr = new ast);
            ptr->type = "function";
        }else if(c == ')'){
            if(stack.size() > 1 && (stack.back().front()->type != "function" && stack.back().front()->type != "ast")){
                throw;
            }
            if(stack.back().front()->type == "function"){
                stack.back().front()->sub.push_back(stack.back().back());
                stack.back().pop_back();
            }else if(stack.back().front()->type == "ast"){
                // void...
            }
            stack[stack.size() - 2].front()->sub.push_back(stack.back().back());
            stack.pop_back();
            ptr = nullptr;
        }else if(c == '['){
            stack.resize(stack.size() + 1);
            stack.back().push_back(ptr = new ast);
            ptr->type = "list";
            ptr = nullptr;
        }else if(c == ']'){
            if(stack.size() > 1 && stack.back().front()->type != "list"){
                throw;
            }
            stack.back().front()->sub.push_back(stack.back().back());
            stack.back().pop_back();
            if(stack.size() > 1){
                stack[stack.size() - 2].front()->sub.push_back(stack.back().back());
                stack.pop_back();
            }
            ptr = nullptr;
        }else if(ptr && (c == ' ' || c == '\n' || c == '\r')){
            if(ptr->type == "function"){
                // void...
            }else if(ptr->type == "list"){
                // void...
            }else{
                stack.back().front()->sub.push_back(stack.back().back());
                stack.back().pop_back();
            }
            ptr = nullptr;
        }else if(ptr){
            if(!ptr){ stack.back().push_back(ptr = new ast); ptr->type = "token"; }
            ptr->token.push_back(c);
        }
    }
}

int main(){
    interpreter("(main 1 (hoge 2 3 4) [aaa bb (c e [n] [t] o r) 1 22 333] '(+ 6 (fuga 5 4) 3))");

    return 0;
}