elizabeth wei's blog

A follow-up to my previous post about building a toy language interpreter in Go. Throughout this post, I'll be referencing my repo . We'll go over a compiler which translates source code to machine code, and then a VM to execute this machine code. What is a compiler?  A compiler takes source code and translates it to executable machine code . (See my previous post for more details.) The figure below shows the high-level architecture of a simple compiler. Like the interpreter we built previously, our compiler has a lexer and a parser which turn our source code into an AST . This is our compiler's frontend . However, that's where a compiler diverges.  The compiler may translate the AST into at least one internal representation (IR) . The IR(s) may be represented using any data structure (even another AST!), but they should follow two rules: (1) be easy to produce, (2) be easy to translate into the target machine code. The IR can also be optimized...

In this post, I'll be giving a high-level overview of interpreters, why they're interesting, and how they work. I'll be referencing my repo, go_interpreter , which is a simple interpreter written in Go for a toy language. The figure below shows the structure of our interpreter with an example input: What is an interpreter?  An interpreter is a language processor that seems to directly execute the source program on user input: In contrast, a compiler first takes in a source program and translates it to an executable machine code target program. Then, the user can pass in inputs to this target program and get outputs. In general, an interpreter is better at reporting errors since it's processing statements one at a time, and a compiler is faster at generating outputs from inputs. In this post, we're going to go over a simple interpreter that is capable of supporting: integers, booleans, strings, arrays, hashmaps prefix, infix operators index opera...