Re: The 4 negations of Lua

["Soni L." <fakedme@...>]

On 17/09/16 01:43 AM, Tim Hill wrote:
> > On Sep 16, 2016, at 2:38 PM, Soni L. <fakedme@gmail.com 
> > <mailto:fakedme@gmail.com>> wrote:
> >
> > A boolean is a 1-bit number. An integer is a 32- or 64-bit number.
> >
> > Bitwise not applies to both.
> >
> > Bitwise not on a boolean is ((~TRUE)&1), which produces the same 
> > value as (!TRUE).
> >
> > And Rust uses ! for both bool not and bitwise not, granted it does 
> > have a complex and potentially turing-complete type system.
>
> A boolean is a logical type with a value of true or false. It may 
> internally be represented as a single bit, but that is an 
> implementation detail. Bitwise inversion (a more accurate name for 
> bitwise NOT) does not apply to booleans, any more than it applies to hats.
>
> C and its various offspring frequently allow an integer value to be 
> INTERPRETED in a boolean manner (using the zero vs non-zero 
> convention). For this reason, in this class of language, it is valid 
> to use boolean operators on integers (though with caution), since the 
> integer type is overloaded. This is not the case for Lua, so your 
> assertion is incorrect.
>
> —Tim
Is there any good reason to not do it the Rust way? Lua has a separate 
boolean type, just like Rust. You can't add/subtract/multiply/divide a 
Rust boolean with a Rust integer and you can't 
add/subtract/multiply/divide a Lua boolean with a Lua integer. But what 
Rust does let you do is use bitwise not on a boolean, and it saves an 
operator.

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