Planned↡ On Infixes r←x(F↡)y

x is a scalar integer, vector of integers or matrix. r is the result of applying F to infixes of y as defined by x:

• if x is a positive scalar, it is interpreted as ⟨x⋄1⟩;
• if x is a negative scalar, it is interpreted as ⟨|x⋄|x⟩;
• if x is a vector, it is interpreted as ⍪x;

Each row of x indicates the way infixes are calculated along the corresponding axis of y. The first element is a positive integer and indicates the window size, w. The second element is a positive integer and indicates the skip count, s. The third element is a scalar or vector and indicates the mode; the first element is the mode and the other elements are parameters; modes are explained below; it defaults to 1.

Modes

Mode 1: Keep Shorter at End

The infixes are w↑y, w↑s↓y, w↑s↓s↓y, etc, until the result is empty. If the last infix is shorter, it is kept.

Mode ¯1: Keep Shorter at Start

TBD

Mode 2: Drop Shorter at End

The infixes are w↓y, w↓s↓y, w↓s↓s↓y, etc, until the result is empty. If the last infix is shorter, it is dropped.

Mode ¯2: Drop Shorter at Start

TBD

Mode 3: Apply Transformation at End

The infixes are w↑y, w↑s↓y, w↑s↓s↓y, etc, until the result is empty. If the last infix is shorter, it is transformed with the transformation described by the first parameter, optionally passing the other parameters.

Mode ¯3: Apply Transformation at Start

TBD

Mode 4: Stencil

TBD

Transformations

Transformation 0: Fill

The edges are extended with the parameter.

Transformation 1: Replicate

The left edge is extended with the first value of the list; the right edge is extended with the last value of the list.

Transformation 2: Reverse

The edges are extended by catenating the reverse of the list.

Transformation 3: Mirror

The left edge is extended by catenating the reverse of the tail (1↓) of the list; the right edge is extended by catenating the reverse of the init (¯1↓) of the list.

Transformation 4: Wrap

The edges are extended by catenating the list.

Custom Transformation

If the transformation is a function, it is applied with left argument the list, and right argument the required (extra) length, negative if the left edge is being extended, positive if the right edge is extended.