Strand Assignment

(A1 A2 ... An)←R Assigns the successive items of R to the names.

A1 A2 ... An are assignable names, R is a scalar or vector.

If 1<⍴⍴R, signal a RANK ERROR.

If R is a scalar or one element vector, its item is assigned to each name, as in Ai←⊃⍬⍴R.

Otherwise, assume there are n names in the list:

If n≠⍴R, signal a LENGTH ERROR.

Otherwise, each successive item of R is assigned to each successive name, as in Ai←i⊃R.

For example, (A B C)←⊂⍳3 is the same as A←B←C←⍳3. In contrast, (A B C)←⍳3 is the same as A←1 ⋄ B←2 ⋄ C←3.
Also, (A B C)←(1 2) 'abc' 1.1 is the same as A←1 2 ⋄ B←'abc' ⋄ C←1.1, and (A B)←B A is a simple and efficient way to swap the values of the two names.