helloworld

Some OCaml shenanigans.

Building

• dune build helloworld.exe produces a native executable.
• dune build helloworld.bc produces bytecode output which can be debugged with ocamldebug _build/default/helloworld.bc.
• dune build will do both of the above.

Running

• ./_build/default/helloworld.exe

Debugging

As described in this issue, Dune performs name mangling on modules to avoid name collisions in the OCaml toplevel. The consequence on debugging is that module names are prefixed by Dune during compilation, and the prefix must be included in the module name when setting breakpoints.

For example, helloworld.ml defines the module Helloworld in the toplevel, which Dune mangles into dune__exe__Helloworld.

• ocamldebug _build/default/helloworld.bc starts a debugging session.
• Set a breakpoint using break @dune__exe__<module> <line>, i.e. break @dune__exe__Helloworld 2.
• Run the program using r.
• Go to a specific time using g <time>, i.e. g 0 restarts the program.