Pure employs the textual order which is often considered more intuitive and is also used in mainstream functional languages such as ML and Haskell. (The specificity order also has its advantages, however, and has actually been used with great success in languages such as Aardappel and Hope.)
On the surface, Pure looks similar to modern-style functional languages of the Miranda, ML and Haskell variety, but under the hood it is a much more dynamic language, with macros and reflective capabilities more akin to Lisp. Pure’s algebraic programming style probably appeals most to mathematically inclined programmers, but its interactive programming environment and easy extensibility also make it usable as a (compiled) scripting language for various application areas, such as graphics, multimedia, scientific, system and web programming.
There are plenty of so called "derivations of Maxwell equations", however, I would not claim that they were based on U(1) necessarily. IMO ME are just the integrability conditions for any conserved quantity (continuity equation): take a generic three-form in R^4, then dJ=0 => J=dF. F has six components corresponding to two vectofields in R^3 which depend on the fourth coordinate and satisfy the div and curl relations as in ME ;)
U(1) symmetry (R also works in a classical setting: it's the Lie algebra that matters) is exactly how you get a "generic three-form" to drop out of the action.
I use it for ages (besides emacs). Properly configured it can stick with emacs at ease. The console plugin, however, might benefit from a brush up, e.g. FX, so it could display MathJax/KaTeX or PNG ...
On the surface, Pure looks similar to modern-style functional languages of the Miranda, ML and Haskell variety, but under the hood it is a much more dynamic language, with macros and reflective capabilities more akin to Lisp. Pure’s algebraic programming style probably appeals most to mathematically inclined programmers, but its interactive programming environment and easy extensibility also make it usable as a (compiled) scripting language for various application areas, such as graphics, multimedia, scientific, system and web programming.
cited <-: https://agraef.github.io/pure-lang/quickref/pure-quickref.pd...