Fix the examples. There is misinformation: "Named functions provide fine-tuned control over arithmetic results." The whole message is out of date.

If you want to give me permission to push a feature/bug branch, I can PR this. I might have some more minor wording cleanup when I review more.

% git diff master
diff --git a/README.md b/README.md
index c7a46a3..a8d3325 100644
--- a/README.md
+++ b/README.md
@@ -151,7 +151,7 @@ In contrast, the _posit_ number system is designed to be efficient, symmetric, a
 1. **Economical** - 

The documentation is quite out of data, e.g. it still uses @interval far too much.

Also we should restructure it following the separation into different documentation types described here, i.e. into

• Tutorials
• How-to guides
• Reference documentation (API)
• Background explanations

Currently there's only an explicit cast for IntegerType.
It might be useful to have casts for other integer types as well.

Given that AC_ARG_ENABLE is for boolean flags, its user interface doesn't match up with its intended purpose very well. Instead of two yes/no branches, the macro really gives you two present/absent branches, and you have to test the (boolean) value of the flag yourself in the "present" bra