Implement SINGLE function

[Jython1415]

Overview

Implement the SINGLE function for the named-functions library.

Description

Returns the value from a cell range which is the intersection of a row OR a column.

Value Proposition

• Useful for extracting specific values from array intersections
• Complements array operations with precise value extraction
• Helpful for lookup operations where you know the intersection point
• Reduces need for INDEX/MATCH in certain scenarios

Priority

MEDIUM

Category

Array Manipulation

Implementation Notes

• Should return a single value from an array intersection
• Handle cases where intersection is not unique or doesn't exist
• May need to clarify exact behavior vs Excel implementation
• Consider error handling for ambiguous cases
• Research Google Sheets equivalent functionality

Related

Part of Excel function implementation initiative (#51)

[Jython1415]

Implemented in #124