diff options
Diffstat (limited to 'spec')
| -rw-r--r-- | spec/inferred.md | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/spec/inferred.md b/spec/inferred.md index ae2ccd05..4b729225 100644 --- a/spec/inferred.md +++ b/spec/inferred.md @@ -36,6 +36,8 @@ Any BQN array can have a *fill element*, which is a sort of "default" value for A fill element can be either `0`, `' '`, or an array of valid fill elements. If the fill element is an array, then it may also have a fill element (since it is an ordinary BQN array). The fill element is meant to describe the shared structure of the elements of an array: for example, the fill element of an array of numbers should be `0`, while the fill element for an array of variable-length lists should probably be `⟨⟩`. However, the fill element, unlike other inferred properties, does not satisfy any particular constraints that relate it to its array. +In addition to the requirements below, the fill element for the value of a string literal is `' '`. + ### Required functions Combinators `⊣⊢!˙˜´˝∘○⊸⟜⊘◶⍟` do not affect fill element computation: if the combinator calls a function that computes a fill element, then that fill element must be retained if the result is passed to other functions or returned. `⍟` constructs arrays if its right operand is or contains arrays, and the fill elements of these arrays are not specified; converting `𝕩` to a fill element is a reasonable choice in some cases but not others. |