> ## Documentation Index
> Fetch the complete documentation index at: https://soul-lang.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Variables and Types

> Understanding Soul's dynamic type system and variable declarations

## Dynamic Typing

Soul is dynamically typed, meaning variables don't need type declarations. The type is determined at runtime based on the assigned value.

## Variable Declaration

Variables are created upon first assignment using the `=` operator:

```javascript theme={null}
name = "Alice"           // String
age = 25                // Number
isStudent = false       // Boolean
data = null            // Null
```

<Note>
  Soul doesn't use keywords like `var`, `let`, or `const`. Simply assign a value to create a variable.
</Note>

## Primitive Types

### Numbers

Soul uses 64-bit floating-point numbers with high-precision decimal implementation to avoid common floating-point issues:

```javascript theme={null}
integer = 100
decimal = 3.14159
scientific = 1.23e-4
calculation = 0.1 + 0.2  // Correctly equals 0.3
```

### Strings

Strings are UTF-8 encoded and can use three different quote styles:

<CodeGroup>
  ```javascript Double Quotes theme={null}
  message = "Hello, World!"
  multiline = "Line 1
  Line 2"
  ```

  ```javascript Single Quotes theme={null}
  name = 'Soul'
  path = 'C:\Users\file.txt'  # No escaping needed
  ```

  ```javascript Backticks theme={null}
  template = `Hello, ${name}!`
  rawString = `No \n escaping`
  ```
</CodeGroup>

### Booleans

Boolean values are `true` or `false`:

```javascript theme={null}
isReady = true
isComplete = false

// Falsy values: false, null, 0, ""
// Everything else is truthy
```

### Null

Represents the intentional absence of a value:

```javascript theme={null}
result = null

// Null is falsy in conditions
if (!result) {
    print("No result yet")
}
```

## Type Checking

Use built-in functions to check types at runtime:

```javascript theme={null}
value = 42

if (typeof(value) == "number") {
    print("It's a number!")
}

// Common type checks
isString = typeof("hello") == "string"
isBoolean = typeof(true) == "boolean"
isNull = value == null
```

## Type Conversion

Soul provides functions for explicit type conversion:

```javascript theme={null}
// String to Number
age = Number("25")          // 25
price = Number("19.99")     // 19.99

// Number to String
text = String(42)           // "42"
formatted = String(3.14159) // "3.14159"

// Boolean conversion
bool1 = Boolean(1)          // true
bool2 = Boolean("")         // false
bool3 = Boolean("false")    // true (non-empty string)
```

## Variable Scope

Variables follow lexical scoping rules:

```javascript theme={null}
globalVar = "I'm global"

soul myFunction() {
    localVar = "I'm local"
    
    if (true) {
        blockVar = "I'm in a block"
        print(globalVar)    // ✓ Accessible
        print(localVar)     // ✓ Accessible
    }
    
    print(blockVar)         // ✓ Still accessible
}

print(localVar)             // ✗ Error: undefined variable
```

<Warning>
  Soul doesn't have block-scoped variables like JavaScript's `let` and `const`. Variables are function-scoped.
</Warning>

## Best Practices

<CardGroup cols={2}>
  <Card title="Use Descriptive Names" icon="tag">
    ```javascript theme={null}
    // Good
    userName = "Alice"
    isLoggedIn = true

    // Avoid
    u = "Alice"
    flag = true
    ```
  </Card>

  <Card title="Initialize Variables" icon="check">
    ```javascript theme={null}
    // Good - clear intent
    count = 0
    items = []

    // Avoid - unclear
    count = null
    ```
  </Card>
</CardGroup>