What is the 'module wall'?

Hello, I came across a blog post about codoc, titled Improving the OCaml documentation toolchain. This post mentions:

In the 2014 OCaml workshop presentation (abstract, slides, video), we mentioned the ‘module wall’ for documentation and this attempts to fix it.

However, I could not find a mention of the ‘module wall’ in any of those links (for the video, in the transcript); can anyone explain what the ‘module wall’ refers to?

Meta: this Discourse needs a ‘Documentation’ category. It would cover questions about ocamldoc, odoc, and codoc.


I suspect that it’s referring to the fact that ocamldoc can’t create cross-references to external modules. So, while you can write syntax to link to the stdlib List module, for example, from your own code’s doc comments, ocamldoc won’t resolve the link.

odoc, odig and their related tools and libraries help fix this issue by drawing on information from all installed libraries rather than just local code. This helps get around that particular limitation of the ocamldoc tool.