[SUGGESTION] Support (some) C++ alternative tokens

[JohelEGP]

I prefer writing (and, or) to (&&, ||). Currently, they're treated as identifiers. So cppfront emits an error if used C++1-correctly (x = y and z;, 3 identifiers in a row is ill-formed), or emits bad C++1 code (x = and;).

https://github.com/hsutter/cppfront/wiki/Design-note%3A-Postfix-unary-operators-vs-binary-operators talks about "alternative tokens". It seems they were supported at some point before this repository was published.

Will your feature suggestion eliminate X% of security vulnerabilities of a given kind in current C++ code? No (my guess).

Will your feature suggestion automate or eliminate X% of current C++ guidance literature? No (my guess).

Describe alternatives you've considered.

1. Rejecting the suggestion. It goes against https://github.com/hsutter/cppfront/blob/main/.github/ISSUE_TEMPLATE/suggestion.md?plain=1#L10-L13 (it'd be easier to read the source if https://sembr.org/ was followed).
2. Recognize them and

• diagnose an use and suggest its alternative, or
• try to emit valid C++ identifiers in their place (e.g., renaming to _and, with no portable way to name them from C++1).

[msadeqhe]

I think logical operators and, or and not are completely different from bitwise operators bitand, bitor, xor and compl, because bitwise operators calculate the result of expressions just like +, -, *, / and other arithmetic operators but logical operators are for decision making similar to is and as keywords in C++2. Therefore it's reasonable to have &&, || and ! as keywords and, or and not similar to is and as, but bitwise operators &, |, ^ and ~ are arithmetic operators and they should not be keywords.

[AbhinavK00]

I think having the bitwise operators spelled out would eliminate more ambiguity than spelling out the logical operators. For example:

a&&b; //what if a and b are not bool? This is the kind of context cpp2 tries to eliminate ig?

That would also reserve ^ for pointer deference(wow!!) and could also eliminate ambiguity between bit shift operators and when writing template template parameters.

[JohelEGP]

not is another one I use. So much that I have Clang-Format insert a space after ! so that it stands out in case I forget to use it (! x -> not x).

In Cpp2, they should be keywords, not alternative tokens. Then there's no chance you can use it weirdly, like in Cpp1 (e.g. x and = y;).

[AbhinavK00]

How would we write x != y with this change? Or is the plan to support both tokens?

[JohelEGP]

I did notice that not_eq is a thing when checking out https://eel.is/c++draft/lex.digraph as I wrote this proposal.

I'm not proposing banning using operators. So you choose to write it however you like. Including using std::not_equal(x, y).

[JohelEGP]

There's some mentions of an and keyword and more starting at #152 (comment).

[JohelEGP]

I've opened #328 for the lack of diagnostics.
I'm closing this in favor of simplicity.