Hello everyone. I have an application (a calculator repl [1]) and I'm looking to convert it into an package that provides both library and executable. I'm looking for suggestions for what might be a good API for such a library. I'm not looking for an extended code review, just the placement of functions in modules, and which functions to export. The current source tree looks like this. src/ $ tree . . ├── Calculator │ ├── Color.hs -- Colored output │ ├── Evaluator │ │ ├── Base.hs -- Common evaluation functions │ │ ├── Cmd.hs -- Evaluate special commands │ │ ├── Expr.hs -- Expression evaluation │ │ ├── Func.hs -- Convert specification for a function into a mathematical function │ │ └── Statement.hs -- Evaluate either expression or command │ ├── Help.hs -- Help message │ ├── Parser │ │ ├── Base.hs -- Common parsers, number, id etc. │ │ ├── Cmd.hs │ │ ├── Expr.hs │ │ └── Statement.hs │ └── Prim -- Primitives │ ├── Bindings.hs -- Variable and Function Bindings │ ├── Cmd.hs │ ├── Definitions.hs -- Basic definitions, pre-defined variables and functions etc. │ ├── Expr.hs │ ├── Function.hs -- Tried to formalize the notion of a function of multiple arguments without currying. │ └── Statement.hs ├── Main.hs └── Model └── Arithmetic.hs -- A calculator model built using Text.ParserCombinators.Parsec.Expr (for model testing) I'm trying to have a library because I want to use a lot of the functionality provided by calculator in plot-lab [2], which is a plotting application. I want to have a stable API, because I don't want to irresponsibly keep changing it according to my personal needs. [1] : https://github.com/sumitsahrawat/calculator [2] : https://github.com/sumitsahrawat/plot-lab -- Regards Sumit Sahrawat