Variables support

[wojciechczerniak]

Description

Our previous formula engine had support for custom variables. The use case was that we can assign a value to a constant name. If we could assign anything a cell could hold we could assign range reference to a name.

Which gives us NamedRanges support. Worth considering.

Example

parser.setVariable('MY_VARIABLE', 5);
parser.setVariable('fooBar', 10);

parser.parse('(1 + MY_VARIABLE + (5 * fooBar)) / fooBar'); // returns `5.6`

API proposal

public setVariable(name: string, value: CellValue);
public getVariable(name: string): CellValue;

Local and global scope

There should be a global (workbook/engine) and local (worksheet) scope of variables. We can add an argument to the API proposal mentioned above.

Reference

https://github.com/handsontable/formula-parser

[wojciechczerniak]

This would solve #5 with:

engine.setVariable('TRUE', `TRUE()`);
engine.setVariable('FALSE', `FALSE()`);

[wojciechczerniak]

Obsolete spec. Named Expressions #126 are variables on steroids and are a part of the ODFF spec