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Document C string literal tokens.
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‎src/expressions/literal-expr.md

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>    | [BYTE_LITERAL]\
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>    | [BYTE_STRING_LITERAL]\
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>    | [RAW_BYTE_STRING_LITERAL]\
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>    | [C_STRING_LITERAL]\
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>    | [RAW_C_STRING_LITERAL]\
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>    | [INTEGER_LITERAL]\
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>    | [FLOAT_LITERAL]\
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>    | `true` | `false`
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> **Note**: This section is incomplete.
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## C string literal expressions
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A C string literal expression consists of a single [C_STRING_LITERAL] or [RAW_C_STRING_LITERAL] token.
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> **Note**: This section is incomplete.
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## Integer literal expressions
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An integer literal expression consists of a single [INTEGER_LITERAL] token.
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[BYTE_LITERAL]: ../tokens.md#byte-literals
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[BYTE_STRING_LITERAL]: ../tokens.md#byte-string-literals
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[RAW_BYTE_STRING_LITERAL]: ../tokens.md#raw-byte-string-literals
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[C_STRING_LITERAL]: ../tokens.md#c-string-literals
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[RAW_C_STRING_LITERAL]: ../tokens.md#raw-c-string-literals
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[INTEGER_LITERAL]: ../tokens.md#integer-literals
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[FLOAT_LITERAL]: ../tokens.md#floating-point-literals

‎src/tokens.md

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#### Characters and strings
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| | Example | `#` sets\* | Characters | Escapes |
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|----------------------------------------------|-----------------|------------|-------------|---------------------|
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| [Character](#character-literals) | `'H'` | 0 | All Unicode | [Quote](#quote-escapes) & [ASCII](#ascii-escapes) & [Unicode](#unicode-escapes) |
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| [String](#string-literals) | `"hello"` | 0 | All Unicode | [Quote](#quote-escapes) & [ASCII](#ascii-escapes) & [Unicode](#unicode-escapes) |
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| [Raw string](#raw-string-literals) | `r#"hello"#` | <256 | All Unicode | `N/A` |
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| [Byte](#byte-literals) | `b'H'` | 0 | All ASCII | [Quote](#quote-escapes) & [Byte](#byte-escapes) |
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| [Byte string](#byte-string-literals) | `b"hello"` | 0 | All ASCII | [Quote](#quote-escapes) & [Byte](#byte-escapes) |
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| [Raw byte string](#raw-byte-string-literals) | `br#"hello"#` | <256 | All ASCII | `N/A` |
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| | Example | `#` sets\* | Characters | Escapes |
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|----------------------------------------------|-----------------|------------|-----------------|---------------------|
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| [Character](#character-literals) | `'H'` | 0 | All Unicode | [Quote](#quote-escapes) & [ASCII](#ascii-escapes) & [Unicode](#unicode-escapes) |
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| [String](#string-literals) | `"hello"` | 0 | All Unicode | [Quote](#quote-escapes) & [ASCII](#ascii-escapes) & [Unicode](#unicode-escapes) |
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| [Raw string](#raw-string-literals) | `r#"hello"#` | <256 | All Unicode | `N/A` |
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| [Byte](#byte-literals) | `b'H'` | 0 | All ASCII | [Quote](#quote-escapes) & [Byte](#byte-escapes) |
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| [Byte string](#byte-string-literals) | `b"hello"` | 0 | All ASCII | [Quote](#quote-escapes) & [Byte](#byte-escapes) |
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| [Raw byte string](#raw-byte-string-literals) | `br#"hello"#` | <256 | All ASCII | `N/A` |
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| [C string](#c-string-literals) | `c"hello"` | 0 | non-`NUL` ASCII | [Quote](#quote-escapes) & [Byte](#byte-escapes) |
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| [Raw C string](#raw-c-string-literals) | `cr#"hello"#` | <256 | non-`NUL` ASCII | `N/A` |
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\* The number of `#`s on each side of the same literal must be equivalent.
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b"\\x52"; br"\x52"; // \x52
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```
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### C string and raw C string literals
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#### C string literals
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> **<sup>Lexer</sup>**\
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> C_STRING_LITERAL :\
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> &nbsp;&nbsp; `c"` ( ASCII_FOR_C_STRING | BYTE_ESCAPE | STRING_CONTINUE )<sup>\*</sup> `"` SUFFIX<sup>?</sup>
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>
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> ASCII_FOR_C_STRING :\
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> &nbsp;&nbsp; _any non-NUL ASCII (i.e 0x01 to 0x7F), except_ `"`, `\` _and IsolatedCR_
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A non-raw _C string literal_ is a sequence of ASCII characters and _escapes_,
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preceded by the characters `U+0063` (`c`) and `U+0022` (double-quote), and
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followed by the character `U+0022`. If the character `U+0022` is present within
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the literal, it must be _escaped_ by a preceding `U+005C` (`\`) character.
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Alternatively, a C string literal can be a _raw C string literal_, defined
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below. The type of a C string literal is `&core::ffi::CStr`.
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Some additional _escapes_ are available in either C or non-raw C string
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literals. An escape starts with a `U+005C` (`\`) and continues with one of the
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following forms:
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* A _byte escape_ escape starts with `U+0078` (`x`) and is followed by exactly
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two _hex digits_. It denotes the byte equal to the provided hex value. The
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byte escape sequence `\x00` is forbidden, as C strings may not contain `NUL`.
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* A _whitespace escape_ is one of the characters `U+006E` (`n`), `U+0072`
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(`r`), or `U+0074` (`t`), denoting the bytes values `0x0A` (ASCII LF),
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`0x0D` (ASCII CR) or `0x09` (ASCII HT) respectively.
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* The _backslash escape_ is the character `U+005C` (`\`) which must be
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escaped in order to denote its ASCII encoding `0x5C`.
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#### Raw C string literals
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> **<sup>Lexer</sup>**\
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> RAW_C_STRING_LITERAL :\
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> &nbsp;&nbsp; `cr` RAW_C_STRING_CONTENT SUFFIX<sup>?</sup>
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>
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> RAW_C_STRING_CONTENT :\
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> &nbsp;&nbsp; &nbsp;&nbsp; `"` ASCII_EXCEPT_NUL<sup>* (non-greedy)</sup> `"`\
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> &nbsp;&nbsp; | `#` RAW_C_STRING_CONTENT `#`
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>
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> ASCII_EXCEPT_NUL :\
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> &nbsp;&nbsp; _any non-NUL ASCII (i.e. 0x01 to 0x7F)_
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Raw C string literals do not process any escapes. They start with the
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character `U+0063` (`c`), followed by `U+0072` (`r`), followed by fewer than 256
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of the character `U+0023` (`#`), and a `U+0022` (double-quote) character. The
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_raw string body_ can contain any sequence of non-`NUL` ASCII characters and is terminated
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only by another `U+0022` (double-quote) character, followed by the same number of
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`U+0023` (`#`) characters that preceded the opening `U+0022` (double-quote)
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character. A raw C string literal can not contain any non-ASCII byte.
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All characters contained in the raw string body represent their ASCII encoding,
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the characters `U+0022` (double-quote) (except when followed by at least as
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many `U+0023` (`#`) characters as were used to start the raw string literal) or
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`U+005C` (`\`) do not have any special meaning.
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Examples for C string literals:
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```rust
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c"foo"; cr"foo"; // foo
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c"\"foo\""; cr#""foo""#; // "foo"
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c"foo #\"# bar";
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cr##"foo #"# bar"##; // foo #"# bar
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c"\x52"; c"R"; cr"R"; // R
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c"\\x52"; cr"\x52"; // \x52
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```
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### Number literals
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A _number literal_ is either an _integer literal_ or a _floating-point

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