integration/luprex/core/cpp/luaconsole.hpp

//////////////////////////////////////////////////////
//
// LuaConsole:
//
// Used to parse commands that are being interactively typed
// in by a user.  The common usage pattern is:
//
//    1. Print the prompt suggested by 'get_prompt'.
//    2. Read a line of text from stdin.
//    3. Add the line to the LuaConsole using 'add'.
//    4. Get the command words using 'get_command'.
//    5. If the command is empty, do nothing.
//    6. If the command is nonempty, execute it.
//
// The LuaConsole expects you to type one of three things:
//
//   * Valid Lua Code.
//   * Valid Lua Code preceded by '=' as shorthand for 'return'
//   * A slash-command.
//
// The 'get_command' returned by the luaconsole can be one of
// the following:
//
//    empty vector   - still collecting input: do nothing.
//    lua <expr>     - found a lua command: execute it as lua.
//    syntax <words> - detected a syntax error: print the error.
//    word word ...  - read a slash-command: execute the command.
//
//////////////////////////////////////////////////////

#ifndef LUACONSOLE_HPP
#define LUACONSOLE_HPP

#include <string>
#include "luastack.hpp"

class LuaConsole {
public:
    using StringVec = std::vector<std::string>;

private:
    lua_State *lua_state_;
    std::string raw_input_;
    int lines_;
    StringVec words_;
    std::string prompt_;

    void clear_raw_input();

public:
    LuaConsole();
    ~LuaConsole();

    // Fetch the recommended prompt.
    //
    // You should update the prompt immediately after 'add'.
    //
    const std::string &get_prompt() { return prompt_; }
    
    // Fetch the command to execute.
    //
    // You should fetch the command after calling 'add'.
    // Returns the empty vector if there is no command.
    // If there is a command, the first word is the command word.
    // See the file comment for certain built-in command words.
    // 
    StringVec get_command();

    // Add a line of text that was just read from the console.
    //
    void add(std::string line);

};

#endif // LUACONSOLE_HPP