# Crafting Interpreters

https://craftinginterpreters.com/

Compilers and interpreters are same same but different. Compiling is an implementation technique where you translate a source language to a lower-level form (normally) and don't execute it. Interpreters execute the source code immediately, but many interpreters translate the code to another form first which means they have a compiler.

Compilers are made up of some to all of these steps:

Front End:

• Scanning (lexical analysis) to tokens
• Parsing to a nested structure of the grammar (abstract syntax tree)
• Static analysis (binding, resolution, scope, type checking for typed languages) this info can be added as attributes to the AST or to a symbol table.

Middle End:

• Intermediate Representations (interface between source and destination implementations)
• Optimization

Back End:

• Code generation (CPU instructions or byte-code/p-code)
• Virtual Machine (emulate a chip written in a language with wide support)
• Runtime (inserted into executable)

Shortcuts:

• Single pass compiler (compile on first read without revisiting)
• Tree walk interpreters (evaluate each node on AST at a time)
• Transpiler (compile to another source language)
• Just in time (compile to native on the clients architecture)