. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 319 15.1. 使用 Box 指向堆上数据 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . compatible versions Adding rand v0.8.5 (available: v0.9.0) Compiling proc-macro2 v1.0.93 Compiling unicode-ident v1.0.17 Compiling libc v0.2.170 Compiling cfg-if v1.0.0 Compiling byteorder v1.5.0 Compiling 类型的大小为四个字节 (four bytes)，并代表了一个 Unicode 标量值（Unicode Scalar Value），这意味着它可以比 ASCII 表示更多内容。在 Rust 中，带变音符号的字母 （Accented letters），中文、日文、韩文等字符，emoji（绘文字）以及零长度的空白字符都是 有效的 char 值。Unicode 标量值包含从 U+0000 到 U+D7FF 和 U+E000

percent-decoded and is now a byte string. By default, this method decodes the argument as utf-8 and returns a unicode string, but this may be overridden in subclasses. This method is used as a filter for both get_argument() lifetime to the current browser session. Secure cookies may contain arbitrary byte values, not just unicode strings (unlike regular cookies) Similar to set_cookie, the effect of this method will not be seen near-equivalents in the standard library (the differences mainly relate to handling of bytes and unicode strings, and were more relevant in Python 2). In new code, the standard library functions are encouraged

url_escape() url_unescape()json_encode() json_decode() Byte/unicode conversions utf8() to_unicode() native_str() to_basestring() recursive_unicode() Miscellaneous functions linkify() squeeze() tornado percent-decoded and is now a byte string. By default, this method decodes the argument as utf-8 and returns a unicode string, but this may be overridden in subclasses. This method is used as a filter for both get_argument() lifetime to the current browser session. Secure cookies may contain arbitrary byte values, not just unicode strings (unlike regular cookies) Similar to set_cookie, the effect of this method will not be seen