How do “lang-servers” work within VScode? How can an extension figure out an entirely custom codebase and its functions and give me definitions on just right click?

Question

It is crazy useful and ive no idea how it works.

Server makes me think it is a web service but it works even with like completely local code that is entirely custom and stuff.

All i know is i tend to need to compile the codebase once before it gets the new function definitions.

In: 5

Answer 1

> How can an extension figure out an entirely custom codebase

Literally the same way the compiler can do the same thing. In fact, for a lot of language server implementations, they just use part of the actual compiler (the parser, the lexical, syntax and semantic analyzers), the output of which is [a tree representation](https://en.wikipedia.org/wiki/Abstract_syntax_tree) of all the things in the code, plus the errors the analyzers found.