rebol - 在 REBOL 3 中复制/部分成对

Question

help copy 关于copy 有以下说法:

USAGE:
   COPY value /part length /deep /types kinds

DESCRIPTION:
   Copies a series, object, or other value.
   COPY is an action value.

ARGUMENTS:
   value -- At position (series! port! map! object! bitset! any-function!)

REFINEMENTS:
   /part -- Limits to a given length or position
       length (number! series! pair!)
   /deep -- Also copies series values within the block
   /types -- What datatypes to copy
       kinds (typeset! datatype!)

/part 细化可以采用number!、series! 或pair!。我无法让 pair! 工作。 (我还没试过series!呢。)这不是实现了吗？如果是，它是如何工作的？

Answer 1

/part 对! 优化适用于图像。该对与 x/y 坐标相关，如

>> img: load %image.png 
== make image! [519x391 #{
1D2F9F1D2F9F1C2E9E1C2E9E1B2D9D1B2D9D1B2D9D1B2D9D1D2F9F1C2E9E
1A2C9C192B9B192B9B1A2C9C1B2D9D1C2E9E1D2EA01...
>> copy/part img 2x2
== make image! [2x2 #{
1D2F9F1D2F9F1D2F9F1D2F9F
}]

REBOL/View Image Datatype

这里有一个例子，/part series! 是如何工作的

>> s: [a b c d e f g]
== [a b c d e f g]
>> ser: skip s 3
== [d e f g]
>> copy/part s ser
== [a b c]