Other languages internals

PHP

• PHP Internals Book
• Zend Engine 2 Opcodes
• HHVM Bytecode Specification

Perl

• Perl 5 Internals
• Parrot

Lua

• The Implementation of Lua 5.0 (PDF) one page HTML
• The Virtual Machine of Lua 5.0 (PDF)
• A No-Frills Introduction to Lua 5.1 VM Instructions (PDF)

Java

• The Structure of the Java Virtual Machine
• Inside the Java Virtual Machine 2nd edition: 9 free chapters out of 20
• JVM Internals blog
• Dalvik VM bytecode format

Python

• Design of CPython's Compiler
• Python internals: Working with Python ASTs
• Python’s Innards
• Python Compiler Internals (PDF)
• Python Bytecode Instructions

Ruby

• Ruby Under a Microscope
• Ruby Internals: 70 slides
• YARV bytecode - YARV instruction set

Javascript

• The V8 JavaScript Engine (PDF)
• V8 Internals: Building a High Performance JavaScript Engine

Forth

• A sometimes minimal FORTH compiler and tutorial for Linux (part 2)

Others

• The Potion Language
• The Implementation of the Icon Programming Language (PDF)