Whitespace
Whitespace is any non-empty string containing only characters that have the
Pattern_White_Space
Unicode property, namely:
U+0009
(horizontal tab,'\t'
)U+000A
(line feed,'\n'
)U+000B
(vertical tab)U+000C
(form feed)U+000D
(carriage return,'\r'
)U+0020
(space,' '
)U+0085
(next line)U+200E
(left-to-right mark)U+200F
(right-to-left mark)U+2028
(line separator)U+2029
(paragraph separator)
Rust is a "free-form" language, meaning that all forms of whitespace serve only to separate tokens in the grammar, and have no semantic significance.
A Rust program has identical meaning if each whitespace element is replaced with any other legal whitespace element, such as a single space character.