|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 shorthand for A←B←C←⍳3. In contrast, (A B C)←⍳3 is shorthand for A←1 ⋄ B←2 ⋄ C←3.
Note that (A B)←B A is a simple and efficient way to swap the values of the two names.