* Remove namespaces
* Prefer `bool operator==`, not `friend auto operator==`
* Prefer not to use `using`
* Use a `constexpr` function instead of a template for `flipTable`
Identify files by (device, inode), not by path, so that symlinks,
relative paths, case-insensitive paths, or other edge cases
do not result in double includes.
Part of that condition's purpose is to ensure that we read the correct
lexer state; but it's possible now for the fstack to be non-empty
*before* the lexer state is registered, i.e. if there is an error
in the function that registers it.
This causes a NULL pointer deref.
- The '#' component for type 's' now escapes the string characters
- The '#' component for type 'f' now prints a precision suffix
- The new 'q' component specifies a precision value
* Implement custom generic tagged union `Either`
This should be more efficient than `std::variant`, while still
keeping runtime safety as it `assert`s when `get`ting values.
* Use `Either` for RPN expressions
* Use `Either` for file stack node data
* Use `Either` for `File` buffer
* Use `Either` for `STRFMT` args
* Use `Either` for RGBLINK symbol values
* Support an equivalent of `std::monostate` for `Either`
* Use `Either` for lexer tokens
* Use `Either` for symbol values
* Use `Either` for lexer mmap/buffer state
- FIX: `Label & const` was not actually doing the `& const` masking
(fixes#1446)
- ADD: `LOW(Label)` can be constant if `Label` is aligned to 8 or more bits
(resolves#1444)
- ADD: `!expr` can be constant 0 if `expr` has any non-zero bits
(resolves#1447)
- `LOW()` and `HIGH()` have their own RPN operator values
(resolves#1445)
The change to RPN values means that the object file version was incremented.
This also refactors unary operators and functions, combining their
evaluation similarly to binary ones.
