IDL 可以将字符串作为代码进行评估吗？
IDL 中是否有任何功能可以允许将字符串作为代码进行计算？
或者，如果做不到这一点，是否有一种很好的动态方式在函数中包含 /KEYWORD ？例如，如果我想询问用户想要什么类型的地图投影，有没有办法可以很好地做到这一点，而无需使用 /Projection_Type 关键字的大量 if/case 语句？
即使用户选项数量很少，这些组合也会导致 if/case 语句很快失控，无法处理所有可能的选项。
Is there any functionality in IDL that will allow it to evaluate a a string as code?
Or, failing that, is there a nice, dynamic way of including /KEYWORD in functions? For example, if I wanted to ask them for what type of map projection the user wants, is there a way to do it nicely, without large if/case statements for the /Projection_Type keyword it needs?
With even a small number of user options, the combinations would cause if/case statements to get out of hand very quickly to handle all the possible options.
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最好的选择是使用 case 语句，因为您不能相信您的用户会为 Projection_Type 输入与您期望的关键字相同的字符串。
不过，如果您打算执行类似的操作，则可以使用 EXECUTE 函数将字符串视为 IDL 语句：
Result = EXECUTE(String [, QuietCompile] [, QuietExecution])编辑后添加，还有 CALL_FUNCTION 和 CALL_PROCEDURE 速度更快，但灵活性可能较差。在 IDL 帮助中查找所有内容，看看哪些对您有用。
The best bet is to use a case statement because you can't trust that your user is going to type in the same string for Projection_Type that you're expecting as in the keyword.
Though if you are set on doing something like this, there is the EXECUTE function that treats a string as an IDL statement:
Result = EXECUTE(String [, QuietCompile] [, QuietExecution])Edited to add, there's also CALL_FUNCTION and CALL_PROCEDURE that are faster but maybe less flexible. Look them all up in the IDL help and see what works for you.