[GSoC] "Language Server Protocol in D" - progress and update thread

[Manish Khurana]

Hi everyone,

I have started working on my GSoC-2019 project "Language Server 
Protocol in D". This newsgroup thread is for posting progress and 
updates about the project.

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About the project
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Language Server Protocol (LSP) is JSON-RPC based protocol for use 
between source code editors or IDEs and servers that provide 
programming language-specific features. The idea behind the LSP 
is to standardize the protocol for how tools and servers 
communicate, so a single Language Server can be re-used in 
multiple development tools, and tools can support languages with 
minimal effort.

As of now, almost every language has a language server and almost 
all editors and IDEs are either having or developing support for 
LSP. D Language also has two language servers - DLS and DCD. 
Although these two language servers work very well, but they use 
libdparse library for lexing and parsing D source code and hence 
they still lack in some of the features like semantic analysis on 
AST and D's very powerful Compile-Time Function Evaluation (CTFE).

Recent developments in DMD made it available to be used as a 
library. This means the compiler can be reused and tools don’t 
have to re-implement complex features like CTFE. This project 
aims to develop a new fully-functional language server for D 
programming language using dmd library.

More details about project and project roadmap could be found at 
https://docs.google.com/document/d/15ogvupEgfDgX5RqZOqSbO4-Hz7gWOxIONB6H46tjbIc/edit?usp=sharing


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This Month
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* Improve dmd library to be properly used as a library.
* Implement protocol specifications by re-using code from DLS or 
serve-d.
* Add linting (i.e. showing error messages) support.
* Write test for linting.


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Next Month
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* Implement completion request as per specification. Use dmd 
library to get symbols matching the provided input.
* Implement go-to definition request as per specification. Use 
dmd library to find the location of symbol definition in the 
source files.
* Write tests for completion and go-to-definition requests.


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Blockers
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So far no blockers have been encountered.