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\newcommand, \renewcommand, \providecommand 的区别 #29

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shaodongtang opened this issue Oct 13, 2018 · 1 comment

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shaodongtang commented Oct 13, 2018

参考https://tex.stackexchange.com/questions/36175/what-do-newcommand-renewcommand-and-providecommand-do-and-how-do-they-differ
\newcommand 定义一个新命令，如果已经定义了它，则会产生错误。
\renewcommand 重新定义了预定义的命令，如果尚未定义则会发生错误。
\providecommand 定义了一个新命令（如果尚未定义）

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shaodongtang commented Oct 13, 2018

\newcommand 定义命令时，可使用“长参数”，即参数中可带空行或\par
命令；
\newcommand* 定义命令时，则不可以使用“长参数”．

stone-zeng added the 宏编程 label

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