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changes to 9, 10

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ault011 2014-08-04 13:24:30 -07:00 committed by ault011
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@ -613,7 +613,7 @@ The reduced pseudo code demonstrates this clearly:
*[*[a c] *[*[a c] 0 b]] *[*[a c] *[*[a c] 0 b]]
Here, `c` is some formula that produces a **core** when applied to **subject** `a`. This new **core** is then paired with a formula extracted from **axis** `b` within an identical copy of the new **core**. In higher-level languages that compile to Nock, functions that loop recursively often generate **Operator 9**, as it is the easiest way for a function (or **gate**, to use proper Hoon technology) to recall itself with changes made to its data. Here, `c` is some formula that produces a **core** when applied to **subject** `a`. This new **core** is then paired with a formula extracted from **axis** `b` within an identical copy of the new **core**. In higher-level languages that compile to Nock, functions that loop recursively often generate **Operator 9**, as it is the most concise way for a function (or **gate**, to use proper Hoon technology) to recall itself with changes made to its data.
##Op 10: Hint ##Op 10: Hint
@ -625,7 +625,7 @@ Here, `c` is some formula that produces a **core** when applied to **subject** `
As shown above, there are two cases of **Operator 10**. The latter has the formula `[10 b c]`, which then simply reduces to `c`. Although `[10 b c]` has to be semantically equivalent to `c`, it doesn't have to be practically equivalent. Since whatever information in `b` is discarded, a practical interpreter is free to ignore it, or to use it as a hint, as long as it does not affect the results of the computation. As shown above, there are two cases of **Operator 10**. The latter has the formula `[10 b c]`, which then simply reduces to `c`. Although `[10 b c]` has to be semantically equivalent to `c`, it doesn't have to be practically equivalent. Since whatever information in `b` is discarded, a practical interpreter is free to ignore it, or to use it as a hint, as long as it does not affect the results of the computation.
The former case is slightly more complicated. While it may appear that its reduction `*[*[[*[a c] a] 0 3] d]` could be reduced further to simply `[a d]`, as `*[[*[a c] a] 0 3]` could seem to return just `a`. However, there is a possibility that `c` does not terminate, in which case `[a d]` would be incorrect. Therefore, `*[*[[*[a c] a] 0 3] d]` is the most this case can be reduced. This is because **Operator 10** in either case is a hint. If `x` in `[10 x y]` is an atom, we reduce line 37 and `x` is simply discarded. Otherwise, `x` is a cell `[b c]`; b is discarded, but c is computed as a formula and its result is discarded. The former case is slightly more complicated. While it may appear that its reduction `*[*[[*[a c] a] 0 3] d]` could be reduced further to simply `[a d]`, as `*[[*[a c] a] 0 3]` could seem to return just `a`. However, there is a possibility that `c` does not terminate, in which case `[a d]` would be incorrect. Therefore, `*[*[[*[a c] a] 0 3] d]` is the most this case can be reduced. This is because **Operator 10** is a hint. If `x` in `[10 x y]` is an atom, we reduce line 37 and `x` is simply discarded. Otherwise, `x` is a cell `[b c]`; b is discarded, but `c` is computed as a formula and its result is discarded.
Effectively, this mechanism lets us feed both static and dynamic information into the interpreter's hint mechanism. Effectively, this mechanism lets us feed both static and dynamic information into the interpreter's hint mechanism.