Electronic spreadsheet system producing generalized answers including formulas

• US 5,418,902 A
• Filed: 10/12/1993
• Issued: 05/23/1995
• Est. Priority Date: 05/02/1990
• Status: Expired due to Fees

• Current Assignee: International Computers Limited (Fujitsu Limited)
• Original Assignee: International Computers Limited (Fujitsu Limited)
• Inventors: Babb, Edward, West, Vincent D.
• Primary Examiner(s): Herndon, Heather R.
• Assistant Examiner(s): Feild, J.
• Application Number:
  US03/435,844
• Time in Patent Office: 588 Days
• Field of Search: 395/148, 395/149, 364/710.08, 364/700, 364/406, 364/408, 364/401
• US Class Current: 715/234
• CPC Class Codes: G06F 40/18 of spreadsheets form-filling G06F40/174

Abstract

An electronic spreadsheet consists of an array of cells into which a user can enter formulas and values. The contents of the spreadsheet cells are translated into a query in a high-level logic language such as the Pure Logic Language (PLL). The query is then re-written according to the rules of the logic language, to produce an answer. The answer is then translated back into formulas and values which can be displayed on the spreadsheet. The system provides a number of facilities not available on conventional electronic spreadsheets: it provides the ability to give generalised answers containing formulas rather than simply numbers, and provides the ability to solve goal-seeking problems, working backwards from a desired result.

Claims

1. An electronic spreadsheet system comprising:

(a) means for displaying a spreadsheet comprising a plurality of spreadsheet cells,

(b) user interface means for allowing a user to enter input formulas and input values into said spreadsheet cells and for displaying said input formulas and input values in said spreadsheet cells, each said input value being displayed in a respective cell, each said input formula being displayed in a respective cell and including at least one variable whose value corresponds to the value of another cell, the variable being indicated in the displayed input formula by the name of the other cell, and each said input formula including, for modifying the variable, at least one operator or function included in the group consisting of arithmetic, logic, comparison, string and list operators and user-defined functions,

(c) means for reading said input formulas and input values from said spreadsheet cells and for converting each of said input formulas and input values into a respective rule, each rule being associated with a respective cell and including the name of the respective cell and the corresponding input formula or input value and being in a high-level logic language,

(d) means for processing said rules in accordance with the high-level logic language to produce a plurality of simplified rules, each associated with a respective cell,

(e) means for converting said simplified rules into output formulas and output values, output formulas arising when output values are indeterminate, and

(f) means for displaying said output formulas and said output values in the spreadsheet cells, each output value being displayed in a respective cell, each output formula being displayed in a respective cell and including at least one variable whose value is indeterminate and corresponds to the value of another cell, the indeterminate value being indicated in the displayed output formula by the name of the other cell, and each displayed output formula including, for modifying the variable, at least one operator or function included in the group consisting of arithmetic, logic, comparison, string and list operators and user-defined functions.

2. An electronic spreadsheet system comprising:

(a) means for displaying a spreadsheet comprising a plurality of spreadsheet cells,

(b) user interface means for allowing a user to enter input formulas and input values into said spreadsheet cells and for displaying said input formulas and input values in said spreadsheet cells, each said input value being displayed in a respective cells, each said input formula being displayed in a respective cell and including at least one variable whose value corresponds to the value of another cell, the variable being indicated in the displayed input formula by the name of the other cell, and each input formula including, for modifying the variable, at least one operator or logic function included in the group consisting of arithmetic, logic, string and list operators and user-defined functions,

(c) means for reading said input formulas and input values from said spreadsheet cells and for converting each of said input formulas and input values into a respective rule, each rule being associated with a respective cell and including the name of the respective cell and the corresponding input formula or input value and being in a high-level logic language,

(d) means for processing said rules in accordance with the high-level logic language to produce at least one simplified rule, each associated with a respective cell,

(e) means for converting said simplified rule into an output formula, and

(f) means for displaying said output formula in one of the spreadsheet cells, said output formula including at least one variable whose value is indeterminate and corresponds to the value of another cell, the indeterminate value being indicated in the displayed output formula by the name of the other cell, and the displayed output formula including, for modifying the variable, at least one operator or function included in the group consisting of arithmetic, logic, comparison, string and list operators and user-defined functions.

3. A method of operating an electronic spreadsheet system, the method comprising:

(a) displaying a spreadsheet comprising a plurality of spreadsheet cells,

(b) entering input formulas and input values into said spreadsheet cell and displaying said input formulas and input values in said spreadsheet cells, each said input value being displayed in a respective cell, each said input formula being displayed in a respective cell and including at least one variable whose value corresponds to the value of another cell, the variable being indicated in the displayed formula by the name of the other cell, and each input formula including, for modifying the variable, at least one operator or function included in the group consisting of arithmetic, logic, comparison, string and list operators and user-defined functions,

(c) reading said input formulas and input values from said spreadsheet cells and converting each of said input formulas and input values into a respective rule, each rule being associated with a respective cell and including the name of the respective cell and the corresponding input formula or input value and being in a high-level logic language,

(d) processing said rules in accordance with the high-level logic language to produce a plurality of simplified rules, each associated with a respective cell,

(e) converting said simplified rules into output formulas and output values, output formulas arising when output values are indeterminate, and

(f) displaying said output formulas and output values in said spreadsheet cells, each output value being displayed in a respective cell, each output formula being displayed in a respective cell and including at least one variable whose value is indeterminate and corresponds to the value of another cell, the indeterminate value being indicated in the displayed output formula by the name of the other cell, and each displayed output formula including, for modifying the variable, at least one operator or function included in the group consisting of arithmetic, logic, comparison, string and list operators and user-defined functions.