[0] Book of Proof by Richard Hammack https://www.people.vcu.edu/~rhammack/BookOfProof/
[1] Linear Algebra: Step by Step by Kuldeep Singh https://www.google.com/books/edition/Linear_Algebra/BJNoAgAA...
[2] Number Theory: Step by Step by Kuldeep Singh https://www.google.com/books/edition/Number_Theory/YZr9DwAAQ...
[3] Undergraduate Analysis: A Working Textbook by Aisling McCluskey and Brian McMaster
https://books.google.com/books?id=7U9HtAEACAAJ&printsec=copy...
There's even more relevant book for you[4]
[4] Foundations of Applied Mathematics by Jeffrey Humpherys, Tyler J. Jarvis, Emily J. Evans
https://books.google.com/books?id=CEc3DwAAQBAJ&pg=PR3&source...
I see that you are desperately trying to distinguish "foundational" and "analysis" contexts from each other. If you are writing a book about analysis, it might be helpful to clarify that in this context you reserve "function" for mappings into ℂ or ℝ, for example [1] defines "function" exclusively as a mapping from a set S to ℝ (without any further requirements on S such as being a subset of ℝⁿ). Note that even under this restricted definition of function, a distribution still is a function.
In a general mathematical context, "function" and "mapping" are usually used synonymously. It is just not the case that such use is restricted to "foundations" only.
It seems to me that squabbles about issues like this are becoming more frequent here on HN, and I am wondering why that is. One hypothesis I have is that there is an influx of people here who learn mathematics through the lens of programs and type theory, and that limits their exposure to "normal" mathematics.
[1] Undergraduate Analysis, Second Edition, by Serge Lang
https://www.amazon.com/Problem-Book-Analysis-Books-Mathemati... https://www.amazon.com/Problems-Solutions-Undergraduate-Anal...
The second one is for Lang's "Undergraduate Analysis" book.