integration/luprex/cpp/luaconsole.cpp

#include <string.h>
#include "luaconsole.hpp"

LuaConsole::LuaConsole() {
    lua_state_ = lua_open();
    clear();
}

LuaConsole::~LuaConsole() {
    lua_close(lua_state_);
}

void LuaConsole::clear() {
    expression_ = "";
    lines_ = 0;
    syntax_ = "";
    action_ = DO_NOTHING;
}
    
void LuaConsole::add(std::string line) {
    if (action_ != DO_NOTHING) {
        clear();
    }
    for (int i = 0; i < int(line.size()); i++) {
        if (line[i] == '\n') line[i] = ' ';
    }
    expression_ += line;
    expression_ += '\n';
    lines_ += 1;

    // Convert leading = to 'return'
    if (expression_[0] == '=') {
        expression_ = std::string("return ") + expression_.substr(1);
    }

    // Analyze slash-commands.
    if (expression_[0] == '/') {
        if (lines_ == 1) {
            action_ = DO_SLASH;
            syntax_ = "";
        } else {
            action_ = DO_SYNTAX;
            syntax_ = "slash command has more than one line";
        }
        return;
    }

    // Analyze lua expressions.
    int top = lua_gettop(lua_state_);
    int status = luaL_loadbuffer(lua_state_, expression_.c_str(), expression_.size(), "=stdin");
    if (status == LUA_ERRSYNTAX)
    {
        const char *eof = "'<eof>'";
        size_t lmsg;
        const char *msg = lua_tolstring(lua_state_, -1, &lmsg);
        const char *tp = msg + lmsg - (sizeof(eof) - 1);
        if (strstr(msg, eof) == tp) {
            syntax_ = "";
            action_ = DO_NOTHING;
        } else {
            syntax_ = msg;
            action_ = DO_SYNTAX;
        }
    } else {
        syntax_ = "";
        action_ = DO_COMMAND;
    }
    lua_settop(lua_state_, top);
}

void LuaConsole::add_stdin() {
    if (action_ != DO_NOTHING) {
        clear();
    }
    const int MAXINPUT = 1000;
    char buf[MAXINPUT];
    fputs(expression_.empty() ? "> " : ">> ", stdout);
    fflush(stdout);
    if (fgets(buf, MAXINPUT, stdin)) {
        size_t len = strlen(buf);
        if (len > 0 && buf[len - 1] == '\n')
            buf[len - 1] = '\0';
        add(buf);
    }
}