Myujth

I don't know the effect of option dsource of ocamlc.the -h option tell me it's undocumented

I know the use of dparsetree and dtypedtree,it can show me the ast

I try to use the option dsource,to a file test.ml,It seems to return me the source code,without the null line and the comment,and at bottom tell me the waring of the source code.

Is it the effect of option dsource?Thanks!

I just spent a few minutes grepping the OCaml compiler sources, and here is what I found.

The -dsource command-line flag sets the dump_source field to true in the Clflags module.

This setting in turn causes the compiler to do something like this in driver/compile.ml when compiling an implementation (.ml) file.

if !Clflags.dump_source then
 fprintf ppf "%a@." Pprintast.structure ast

In other words, it pretty-prints the code part of the AST in a form that looks like source code.

Things look similar for an interface (.mli) file, except that it prints out the signature rather than the code.

Since OCaml has a rather flexible front-end, I would guess this is helpful to see the final result of any syntactic transformations that have been applied to the code. (But I might be wrong, I'm not an OCaml compiler hacker.)

I suggest you start looking at the code in driver/compile.ml if you want to figure out more.

-dsource pretty-prints the AST using the OCaml syntax after desugarring syntax extensions such as camlp4 and ppx.

It's mostly used to debug ppxs. The content is exactly the same as -dparsetree (except in source form, instead of AST).