sequence -- make a sequence

Synopsis

• Usage:
sequence v
• Inputs:
• v,
• Outputs:
• , v if v is a sequence, otherwise a sequence of length 1 containing v

Description

Such a function is needed occasionally to restore uniformity, because a nonempty parenthesized expression with no commas is not parsed as a sequence.

 i1 : sequence() o1 = () o1 : Sequence i2 : sequence(4) o2 = 1 : (4) o2 : Sequence i3 : sequence(4,5) o3 = (4, 5) o3 : Sequence i4 : identity() o4 = () o4 : Sequence i5 : identity(4) o5 = 4 i6 : identity(4,5) o6 = (4, 5) o6 : Sequence

• unsequence -- extract the single element from a sequence of length 1

For the programmer

The object sequence is .