Anonymous recursion: Difference between revisions
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This limitation can be overcome with the understanding that recursion can be factored out into two ideas, i.e. self-reference and evaluation. The self-reference word in Quackery is <code>this</code>, which puts a pointer to the current nest on the data stack (usually just called "the stack") and the evaluation word is <code>do</code>, which takes an item from the stack and evaluates it. So <code>this do</code> is equivalent to <code>recurse</code>. |
This limitation can be overcome with the understanding that recursion can be factored out into two ideas, i.e. self-reference and evaluation. The self-reference word in Quackery is <code>this</code>, which puts a pointer to the current nest on the data stack (usually just called "the stack") and the evaluation word is <code>do</code>, which takes an item from the stack and evaluates it. So <code>this do</code> is equivalent to <code>recurse</code>. |
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The final example fixes the previous example by using <code>this</code> and <code>do</code> to put the pointer to the current nest on the stack at the correct level of nesting and evaluate it within the nested nests. |
The final example fixes the previous example by using <code>this</code> and <code>do</code> to put the pointer to the current nest on the stack at the correct level of nesting and evaluate it within the nested nests. See also [http://rosettacode.org/wiki/Even_or_odd#Quackery:_With_Anonymous_Mutual_Recursion Even or Odd#Quackery: With Anonymous Mutual recursion]. |
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<pre>[ dup 0 < iff |
<pre>[ dup 0 < iff |
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