Variables and Types

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:

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.

Primitive Types

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

Strings

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

message = "Hello, World!"
multiline = "Line 1
Line 2"

name = 'Soul'
path = 'C:\Users\file.txt'  # No escaping needed

template = `Hello, ${name}!`
rawString = `No \n escaping`

Booleans

Boolean values are true or false:

isReady = true
isComplete = false

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

Null

Represents the intentional absence of a value:

result = null

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

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

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)

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.

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

Get Started

Essentials

Dynamic Typing

Variable Declaration

Primitive Types

Numbers

Strings

Booleans

Null

Type Checking

Type Conversion

Variable Scope

Best Practices

Use Descriptive Names

Initialize Variables

​Dynamic Typing

​Variable Declaration

​Primitive Types

​Numbers

​Strings

​Booleans

​Null

​Type Checking

​Type Conversion

​Variable Scope

​Best Practices

Use Descriptive Names

Initialize Variables

Dynamic Typing

Variable Declaration

Primitive Types

Numbers

Strings

Booleans

Null

Type Checking

Type Conversion

Variable Scope

Best Practices