Complement operator (~tilda) is not supported

[pavel-chumakou]

According to B users' reference: "complement operator ~, when applied to an rvalue, turns all 1 bits to 0 and all 0 bits to 1."
But current implementation doesn't support ~ operator with LEXER ERROR: Unknown token ~
Actually ~x = -x - 1, so we can leave without complement operator. But imo it's better to have it.
I implemented it locally on my machine, it's just one notq operator for x86_64:

           Op::Complement { result, arg } => {
                load_arg_to_reg(arg, c!("rax"), output, os);
                sb_appendf(output, c!("    notq %%rax\n"));
               .....

So I can create a pull-request. Not sure how to implement (and test) it for other targets though.

[ellxor]

The implementation of B here follows the 1972 B Reference for the PDP-11 written by Ken Thompson. B was a continually evolving language and fed directly into early versions of C, so it changed quite quickly. I believe you are referring to the 1973 B Reference for the Honeywell 6070.

This later version added quite a few features:

• the bitwise complement unary operator: ~
• the bitwise exclusive or binary operator: ^
• the break keyword inside of while and switch statements
• the default: label added to switch statements
• extended the word size from 16 to 36 bits, which allowed for 4 character literals (e.g. 'hell' as seen in the hello world example, section 7, of Kernighan's B tutorial)