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rustescaping

What is the difference between ASCII escapes and byte escapes in RUST documents?

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I understand perfectly: \x44 will get a "D" because D is the 44th in ASCII (hex)

So \x41 as an example in ASCII escapes

So why does it appear in Byte escapes again? What does "Byte escapes" really mean? Would I get an 8bit byte? no...

In this table it just removes the "maximum value of 7F" description. But this is meaningless. Because ASCII only has a maximum of 0-127. And the compiler forces the maximum value to be 7F. and ofcourse I don't get any 8bit data at last. (Like 11001100.)

So what does this table mean the second time it appears here?

Solution

  • Lets give these tables some context: they come from the Rust Reference: Tokens in the Literals section. Right above these are a table of the different syntax for string and byte string literals:

    characters and strings

    Notice on the far right there are links to the different sub-tables of escape sequences that can be used within each literal type, you've only shown the tables behind the ASCII and Byte links.

    So string literals can use the escape sequences from the "String escapes" table and byte string literals can use escape sequences from the "Byte escapes" table.

    Why have they organized it like this? I have no idea. Why aren't Unicode and ASCII merged into one sub-table? If the control characters are duplicated between the ASCII and Byte sub-tables, why does Quote get its own table instead of being duplicated as well? No idea.

    What does "Byte escapes" really mean? Would I get an 8bit byte? no...

    In this table it just removes the "maximum value of 7F" description. But this is meaningless. Because ASCII only has a maximum of 0-127. And the compiler forces the maximum value to be 7F. and of course I don't get any 8bit data at last. (Like 11001100.)

    Byte strings are not limited to the 7-bits of ASCII nor the confines of valid Unicode values. Perhaps you didn't know byte strings existed? Today is a good day to learn!