等号： = equal single-equal double-equals
下划线： _ underscore
双引号： "" double-quotes
百分号： % percent character
圆括号： () parentheses
boolean： boolean
反斜杠： \ back slash escape sequences
斜杠： / forward- slash
转义字符：
Escape What it does.
\\ Backslash (\)
\' Single- quote (') df
\" Double- quote (")
\a ASCII bell (BEL)
\b ASCII backspace (BS)
\f ASCII formfeed (FF)
\n ASCII linefeed (LF)
\N {name} Character named name in the Unicode database (Unicode only)
\r ASCII carriage return (CR)
\t ASCII horizontal tab (TAB)
\uxxxx Character with 16- bit hex value xxxx (Unicode only)
\Uxxxxxxxx Character with 32- bit hex value xxxxxxxx (Unicode only)
\v ASCII vertical tab (VT)
\ooo Character with octal value oo
\xhh Character with hex value h