Spotfire Ideas Portal
The current custom expression language is adequate for simple expressions, but having a full fledged python interpreter would greatly increase the readability and utility of these expressions/functions. Further, since the current custom expression language is proprietary, moving to an industry standard would make learning spotfire easier and allow developers to become proficient faster.
What you are describing is building an expression within python. I was suggesting having python be available as a language to write expressions in. I.e. add a calculated column and writing the logic for it using python. What you are describing is just updating an expression using python - the underlying expression language is still the proprietary limited language.
I believe this is currently available. I have attached a section of Iron Python code that I use today that builds the custom expression in a cross table dynamically based on the user selection in a slider. So, as the user moves the slider the expression updates.
In the example, the expression is very easy. Just a simple "NEST". You can update this accordingly.
Also, this example just refers to the Horizontal axis. If you wanted to change the vertical axis you would need replace "ColumnAxis" with "RowAxis". To change the values inside the cells you would need to replace "ColumnAxis" with "MeasureAxis". I have placed both of these examples in the code as a comment. They are the last two lines of the code.