Part 1 - Welcome

• We are implementing a language by the name of Lox.
• Successful languages usually come about due to a combination of many small niche languages, domain specific languages.
• Some example of little languages include:
  • yarn
  • Make
  • YAML
  • SQL
  • AWK

General Knowledge

• A compiler takes one language as input and outputs another language.
• Inputting and outputting the same language is called self-hosting.
• You can compile your compiler with another compiler and then used the compiled version of your compiler to compile future versions of your compiler, this is known as bootstrapping

Book Structure

• Part II & Part III each walk you through building a Lox interpreter.
• Each chapter is structured the same:
  • Takes a single language feature.
  • Teaches the concepts.
  • Walks you through an implementation.
• NOTE: The challenges at the end of chapters are exploratory and there for enhanced understanding. If tackling these, make a copy of the project and explore there. The chapters that continue to build assume you have not done any of the challenges.

The Build

• The first interpreter will be built in java with a focus on concepts.
• The second interpreter will be built in C with a focus on speed.

Challenges

1. The 6 domain-specific languages used in the book are make, css, scss, html, markdown, mustache, and yaml.
2. Java Implementation:

public class HelloWorld {
  public static void main (String[] args){
    System.out.println("Hello World!");
  }
}

• Run the java with javac filename.

3. C Implementation:

#include <stdio.h>

int main() {
    printf("Hello World!\n");
    return 0;
}

• Run the c with gcc filename -o outputName.