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ch2_1_defun [2022/03/31 04:56] – adminch2_1_defun [2022/03/31 04:57] (current) – admin
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 === Optional parameters === === Optional parameters ===
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 Since LabLISP version 1.3, it is possible for user to define function with variable number of parameters, using a symbols ''&OPTIONAL'' and ''&REST'' in the list of parameters.   Since LabLISP version 1.3, it is possible for user to define function with variable number of parameters, using a symbols ''&OPTIONAL'' and ''&REST'' in the list of parameters.  
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 The mandatory, optional and rest paramters can be combined. Order of the keywords ''&OPTIONAL'' and ''&REST'' must be kept. That means we can have any number of mandatory parameters, then ''&OPTIONAL'' keyword, after any number of optional parameters, with or without initializers, then ''&REST'', which must be followed by exactly one symbol. The mandatory, optional and rest paramters can be combined. Order of the keywords ''&OPTIONAL'' and ''&REST'' must be kept. That means we can have any number of mandatory parameters, then ''&OPTIONAL'' keyword, after any number of optional parameters, with or without initializers, then ''&REST'', which must be followed by exactly one symbol.
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 +=== Lexical closure ===
  
 Functions have lexical closure. In simple terms, it means that when called, the function body expressions are evaluated in the environment, where the function was defined, and not in the environment where called.  Functions have lexical closure. In simple terms, it means that when called, the function body expressions are evaluated in the environment, where the function was defined, and not in the environment where called. 
ch2_1_defun.1648724187.txt.gz · Last modified: 2022/03/31 04:56 by admin
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