Building the F# compiler

[The-Futurist]

I'm new to this repo and still somewhat of a novice with F#. However I have written full compilers in the past so I'm at home with most of the basic concepts, although I never used tools for creating lexers or parsers before (these were "hand coded").

So I have some questions (if there's a better forum for asking these questions please let me know)

I can see that the basic lexer input file is lex.fsl but there are quite a few other files too (and two other files with .fsl names). Is this file processed automatically when we run a Visual Studio build of FSharp.sln? if so what are the files that get generated?

I have cloned the repo and run the build.cmd and the solution itself builds fine.

There's also a file fslexlex.fs that gives me the impression it was generated but is that true? this seems to suggest it is:

These refer to a file fslexlex.fsl but the repo seems to contain no such file.

Also is build.cmd something we need to run just once after cloning or must it be run for certain kinds of changes too?

Is there any step-by-step documentation of the steps used to go from these lexer/parser input files to generated F# files? Perhaps there's a list of each human editable file that is used as input to the tools and a list of what files are generated?

Any info appreciated.