As a concrete example I wrote a simple interpreter a while back, in golang. Operations would be compiled to a simple bytecode which would be executed at runtim

As a concrete example I wrote a simple interpreter a while back, in golang. Operations would be compiled to a simple bytecode which would be executed at runtime. So: 3 + 4 Would get "compiled" to: PUSH_INT 3 PUSH_INT 4 OP_PLUS As you can imagine this was a virtual stack-machine. After a while I started folding these operations: * If there was a "push int" * And another "push int" * And a maths operation. * Then replace. So in my case I'd first generate the naive version, then have a separate "optimise" pass which would rewrite the program: PUSH_INT 7 NOP NOP NOP NOP A later optimization pass would remove consecutive NOP operations. I made a brief blog-post here: https://blog.steve.fi/adventures_optimizing_a_bytecode_based_scripting_language.html https://blog.steve.fi/adventures_optimizing_a_bytecode_based... There were a couple of bugs found along the way, but the actual implementation of this optimization pass was pretty simple: https://github.com/skx/evalfilter/pull/66/files https://github.com/skx/evalfilter/pull/66/files The biggest issue I had to face was that "1 + 3 => 4" is trivial, but my virtual machine only supports loading integers. So I couldn't collapse "2 * 3.3" into the constant "6.6".