IDL lambda：尝试下标超出范围

Question

idl 8.4 引入了 lambda 功能。我有 IDL 8.6.1 并且 lambda 函数没有完全按照记录工作：

IDL> f = lambda(x : x * x)
IDL> print, call_function(f, findgen(10))
      0.00000      1.00000      4.00000      9.00000      16.0000      25.0000      36.0000      49.0000      64.0000
      81.0000
IDL>  print, f(findgen(10))
IDL$LAMBDAF5 IDL$LAMBDAF5 IDL$LAMBDAF5 IDL$LAMBDAF5 IDL$LAMBDAF5 IDL$LAMBDAF5 IDL$LAMBDAF5 IDL$LAMBDAF5 IDL$LAMBDAF5
IDL$LAMBDAF5
IDL> print, f(5)
% Attempt to subscript F with <INT      (       5)> is out of range.

那么，为什么 f(5) 没有 return 25？

Answer 1

哦，如评论here, this is documented。

Note: To make direct calls on a Lambda function, you should make sure that compile_opt strictarr (or compile_opt idl2) is turned on so that IDL interprets the parentheses as a function call instead of array indices. See COMPILE_OPT for details.

所以 compile_opt strictarr 要么 compile_opt idl2.

不过，我本以为默认情况下可以直接调用。

IDL lambda：尝试下标超出范围

IDL lambda: Attempt to subscript is out of range

idl-programming-language