Tutorials Programming Tutorials, Guides & Best Practices

Not elegant. Easy to forget or misplace deletes. Let's go better.

RAII (Resource Acquisition Is Initialization) is a pattern where resource allocation is tied to object lifetime. When an object goes out of scope, its destructor cleans up.

All objects manage their own memory independently.

In C++11 and newer, also consider:

#include "DSL/Lexer.h"
#include <cctype>
#include <cstdlib>

Lexer::Lexer(const std::string& input) : input(input) {}

char Lexer::currentChar() {
    if (pos < input.size()) {
        return input[pos];
    }
    return '\0';
}

void Lexer::advance() {
    pos++;
}

void Lexer::skipWhitespace() {
    while (std::isspace(currentChar())) {
        advance();
    }
}

Token Lexer::number() {
    size_t start = pos;
    while (std::isdigit(currentChar()) || currentChar() == '.') {
        advance();
    }
    std::string numStr = input.substr(start, pos - start);
    double value = std::strtod(numStr.c_str(), nullptr);
    return { TokenType::Number, numStr, value };
}

Token Lexer::getNextToken() {
    skipWhitespace();

    char current = currentChar();

    if (current == '\0') {
        return { TokenType::EndOfFile, "", 0 };
    }
    if (std::isdigit(current) || current == '.') {
        return number();
    }

    Token token;
    token.text = std::string(1, current);
    token.value = 0;
    switch (current) {
        case '+': token.type = TokenType::Plus; break;
        case '-': token.type = TokenType::Minus; break;
        case '*': token.type = TokenType::Asterisk; break;
        case '/': token.type = TokenType::Slash; break;
        case '(': token.type = TokenType::LParen; break;
        case ')': token.type = TokenType::RParen; break;
        default: token.type = TokenType::Invalid; break;
    }
    advance();
    return token;
}

We’ll implement a recursive-descent parser that constructs an Abstract Syntax Tree (AST) from tokens. Our grammar is defined with standard operator precedence:

• Open the player prefab in the prefab editor.
• Add a NetworkObject component to the player.
• Add a NetworkTransform component to handle the synchronization of the player’s position and rotation.

• Create a new C# script named PlayerController and attach it to the player prefab.
• Implement basic movement logic: