From c7ef3aabb54791b597d4095011ff048c2a13f6ac Mon Sep 17 00:00:00 2001 From: Marshall Lochbaum Date: Sat, 7 Aug 2021 20:57:51 -0400 Subject: Document use of fill elements for merge of empty --- docs/doc/couple.html | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'docs/doc/couple.html') diff --git a/docs/doc/couple.html b/docs/doc/couple.html index 164c0fd5..1923e9d1 100644 --- a/docs/doc/couple.html +++ b/docs/doc/couple.html @@ -65,7 +65,7 @@ ∾ ⥊ ⥊¨ a "ABrstABuvwABxyzCDrstCDuvwCDxyz" -

The way this happens, and the constraint that all inner arrays have the same shape, is closely connected to the concept of an array, and like Table ⌜, Merge might be considered a fundamental way to build up multidimensional arrays from lists. In both cases rank-0 or unit arrays are somewhat special. They are the identity value of a function with Table, and can be produced by Merge inverse, >⁼ on a list, which forces either the outer or inner shape to be empty (BQN chooses >⁼ to be <, but only on an array, as > cannot produce non-arrays). Merge has another catch as well: it cannot produce arrays with a 0 in the shape, except at the end, unless fills can be specified.

+

The way this happens, and the constraint that all inner arrays have the same shape, is closely connected to the concept of an array, and like Table ⌜, Merge might be considered a fundamental way to build up multidimensional arrays from lists. In both cases rank-0 or unit arrays are somewhat special. They are the identity value of a function with Table, and can be produced by Merge inverse, >⁼ on a list, which forces either the outer or inner shape to be empty (BQN chooses >⁼ to be <, but only on an array, as > cannot produce non-arrays). Merge has another catch as well: it cannot produce arrays with a 0 in the shape, except at the end, without relying on a fill element.

↗️
    ⊢ e ← ⟨⟩¨ ↕3
 ⟨ ⟨⟩ ⟨⟩ ⟨⟩ ⟩
     ≢ > e
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