A workbook in Excel is a basically a 2D array of input/output cells. Each cell can have a value with one of following types

  • Blank - an empty value. Mostly for blanks cells or used for optional arguments of functions.

  • Logical - a boolean value

  • Number - an equivalent of double, but without NaN or Infinity. Number also represents dates/timespans through serial datetime.

  • Text - A text of up to 32767 characters

  • Error - One of the excel errors, #DIV/0

In the future, we will call a union of these types a scalar value.

Workbook also contains formulas, a receipies that take a values and calculate a new values. Formulas are used in

  • cells formula - in that case, the output of the formula is written into the cell

  • names - although names are mostly used to refere to a range of cells, they are formulas and thus can contain any formula expression (e.g. 1+2)

  • array formulas - formula changes value of 2D array of cells.

Values used during formula evaluation can have the types that are in cell, but in addition can have also following types:

  • array - a 2D array of scalar values.

  • reference - A reference to a range of cells, possibly non-contiguous.