My editor JOE has a built-in calculator equivalent to a Casio scientific: for example it can do statistics (sum, count, average, standard deviation) on a block of numbers you select in the edit buffer. I use this all the time.
In another project, I wrote a preprocessor for TeX- somewhat like Markdown, so that you can make TeX documents with an easier syntax. One of its features is a built-in calculator/spreadsheet. The idea is that \{1+2+3} is expanded with 6. You can also assign and reference variables \{a=3}. If these appear in a table, you can reference other cells: \{RRD+7} "Get first expression from cell two to the Right Right one Down and add 7 to it".
In another project, I wrote a preprocessor for TeX- somewhat like Markdown, so that you can make TeX documents with an easier syntax. One of its features is a built-in calculator/spreadsheet. The idea is that \{1+2+3} is expanded with 6. You can also assign and reference variables \{a=3}. If these appear in a table, you can reference other cells: \{RRD+7} "Get first expression from cell two to the Right Right one Down and add 7 to it".
https://github.com/jhallen/joes-sandbox/tree/master/doc/nice...
Anyway, I'd like this capability in the editor, will add it someday..