# Partial function application
Midio functions can take other functions as input by using the top-right socket as illustrated bellow. The [`Std CallFunction`](/midio-docs/built-in-nodes/core-std.md#callfunction)function can be used to call functions passed as input.
When the function being used as input has any inputs set, like the `Math Add`function above, which has its `first`input set to `123`*,* the function acts as a [partially applied function](https://en.wikipedia.org/wiki/Partial_application).
This means the `Math Add`function above now only takes one input instead of two. This input can either be supplied as an object with the input name as a key, as we do above, or as a list with only one input, like we show below.
Partial function application can be very useful in situations when you needs to be able to [pass a function](/midio-docs/guides/map-filter-reduce.md) which captures certain data which is only available outside the function.
Partial function application can act as a limited kind of [closure](https://en.wikipedia.org/wiki/Closure_\(computer_programming\)) in those circumstances.
---
# Agent Instructions: Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.
Perform an HTTP GET request on the current page URL with the `ask` query parameter:
```
GET https://docs.midio.com/midio-docs/reference/the-midio-language/partial-function-application.md?ask=
```
The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.
Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.