# Verify Functions

Functions can be validated for their signatures, modifiers, naming patterns, return types, and parameter structures.

To verify functions start by querying all functions present in the project:

```kotlin
Konsist
.scopeFromProject()
.functions()
...
```

In practical scenarios you'll typically want to verify a specific subset of functions - such as those defined inside classes:

```kotlin
Konsist
.scopeFromProject()
.classes()
.functions()
...
```

Konsist API allows to query `local` functions:

```kotlin
Konsist
.scopeFromProject()
.classes()
.functions(includeLocal = true)
...
```

Konsist allows you to verify multiple aspects of a functions. For a complete understanding of the available APIs, refer to the language reference documentation for [KoFunctionDeclaration](https://lemonappdev.github.io/konsist/-konsist%200.17.0/com.lemonappdev.konsist.api.declaration/-ko-function-declaration/index.html).

Let's look at few examples.

## Verify Name

Function names can be validated to ensure they follow project naming conventions and patterns.

Check if function name starts with `get` :

```kotlin
...
.assertTrue {
   it.hasNameStartingWith("get")
}
```

## Verify Modifiers

Function modifiers can be validated to ensure proper encapsulation and access control.

Check if function has `public` or default (also `public`) modifier:

```kotlin
..
.assertTrue {
   it.hasPublicOrDefaultModifier
}
```

## Verify Annotations

Function-level and member annotations can be verified for presence, correct usage, and required attribute values.

Check if function is annotated with `Binding` annotation:

```kotlin
...
.assertTrue {
   it.hasAnnotationOf(Binding::class)
}
```

## **Verify Body Type**

Functions with block bodies (using curly braces) can be validated to ensure compliance with code structure requirements:

<pre class="language-kotlin"><code class="lang-kotlin">...
<strong>.assertTrue { 
</strong>    it.hasBlockBody 
}
</code></pre>

Expression body functions (using single-expression syntax) can be verified to maintain consistent style across the codebase:

```kotlin
...
.assertTrue { 
    it.hasExpressionBody 
}
```

## **Verify Parameters**

Function parameters can be validated for their types, names, modifiers, and annotations to ensure consistent parameter usage.

Check if function has parameter of type `String`:

```kotlin
...
.assertTrue { 
    it.hasParameter { parameter  -> parameter.hasTypeOf(String::class) }
}
```

## **Verify Return Type**

Return types can be checked to ensure functions follow expected return type patterns and contracts.

Check if function has Kotlin collection type:

```kotlin
...
.assertTrue { 
    it.returnType?.sourceDeclaration?.isKotlinCollectionType
}
```

## **Verify Generic Parameters**

Generic type parameters can be validated to ensure proper generic type usage and constraints.

Check if function has type parameters:

```kotlin
...
.assertTrue { 
    it.hasTypeParameters()
}
```

## Verify Generic Type Arguments

Generic type arguments can be checked for correct usage.

Check if return type has no type arguments:

```kotlin
...
.assertFalse {
    it.returnType?.hasTypeArguments()
}
```

## **Verify Top Level**

Top-level functions (functions not declared inside a class) can be specifically queried and validated:

```kotlin
...
.assertTrue { 
    it.isTopLevel
}
```

This helps ensure top-level functions follow project conventions, such as limiting their usage or enforcing specific naming patterns.

##


---

# 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.konsist.lemonappdev.com/veryfying-codebase/verify-functions.md?ask=<question>
```

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.