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Dynamic Typing

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

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Variable Declaration

Variables are created upon first assignment using the = operator: 
name = "Alice"           // String
age = 25                // Number
isStudent = false       // Boolean
data = null            // Null
Soul doesn’t use keywords like var, let, or const. Simply assign a value to create a variable.

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Primitive Types

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Numbers

Soul uses 64-bit floating-point numbers with high-precision decimal implementation to avoid common floating-point issues: 
integer = 100
decimal = 3.14159
scientific = 1.23e-4
calculation = 0.1 + 0.2  // Correctly equals 0.3

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Strings

Strings are UTF-8 encoded and can use three different quote styles: 
message = "Hello, World!"
multiline = "Line 1
Line 2"

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Booleans

Boolean values are true or false: 
isReady = true
isComplete = false

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

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Null

Represents the intentional absence of a value: 
result = null

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

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Type Checking

Use built-in functions to check types at runtime: 
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

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Type Conversion

Soul provides functions for explicit type conversion: 
// 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)

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Variable Scope

Variables follow lexical scoping rules: 
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
Soul doesn’t have block-scoped variables like JavaScript’s let and const. Variables are function-scoped.

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Best Practices

Use Descriptive Names

// Good
userName = "Alice"
isLoggedIn = true

// Avoid
u = "Alice"
flag = true

Initialize Variables

// Good - clear intent
count = 0
items = []

// Avoid - unclear
count = null
⌘I