prefix

Prefix operators in Soul are operators that are applied before their operands. They include increment (++), decrement (--), negation (-), logical NOT (!), and other unary operators that modify or evaluate expressions.

Basic Prefix Operators

The primary prefix operators modify or evaluate expressions:

// Prefix increment
counter = 5
result = ++counter      // counter = 6, result = 6
println(result)         // 6
println(counter)        // 6

// Prefix decrement
counter = 5
result = --counter      // counter = 4, result = 4
println(result)         // 4
println(counter)        // 4

Prefix vs Postfix

Understanding the difference between prefix and postfix operators:

// Prefix: modify first, then use new value
a = 5
result = ++a            // a = 6, result = 6

// Postfix: use current value, then modify
b = 5
result = b++            // result = 5, b = 6

Unary Negation

Use prefix minus for numeric negation:

positive = 42
negative = -positive    // negative = -42

// Double negation
value = -(-42)          // value = 42

// Negation in expressions
result = -(10 + 5)      // result = -15

Logical NOT

Use prefix exclamation mark for logical negation:

isTrue = true
isFalse = !isTrue       // isFalse = false

// NOT with expressions
condition = (age >= 18)
isMinor = !condition    // Opposite of condition

// NOT in conditionals
if (!user.isActive) {
    println("User is inactive")
}

Prefix in Expressions

Use prefix operators within larger expressions:

counter = 10
index = 0

// Prefix in array access
items = [1, 2, 3, 4, 5]
value = items[++index]  // index = 1, value = 2

// Prefix in calculations
total = ++counter * 2   // counter = 11, total = 22

Prefix in Loops

Common usage in loop constructs:

// For loop with prefix increment
for (i = 0; i < 10; ++i) {
    println("Iteration: " + i)
}

// While loop with prefix increment
i = 0
while (++i <= 5) {
    println("Count: " + i)
}

Prefix with Array Processing

Use prefix operators for array manipulation:

items = [10, 20, 30, 40, 50]
index = -1

// Process array elements with prefix
while (++index < items.length()) {
    current = items[index]
    println("Processing: " + current)
}

// Fill array with prefix
numbers = []
value = 0
while (numbers.length() < 5) {
    numbers.push(++value)
}
// numbers = [1, 2, 3, 4, 5]

Prefix in Function Calls

Use prefix operators in function arguments:

counter = 0

soul logWithPreIncrement(value) {
    println("Log #" + value)
}

// Function calls with prefix
logWithPreIncrement(++counter)  // counter = 1, Log #1
logWithPreIncrement(++counter)  // counter = 2, Log #2
logWithPreIncrement(++counter)  // counter = 3, Log #3

Prefix with Object Properties

Apply prefix operators to object properties:

stats = {
    "hits": 0,
    "misses": 0,
    "total": 0
}

// Prefix on object properties
newHits = ++stats.hits      // Increment hits, then get new value
++stats.total               // Increment total count

println("New hits: " + newHits)     // New hits: 1
println("Current hits: " + stats.hits)  // Current hits: 1

Prefix in Conditional Statements

Use prefix operators in conditions:

attempts = 0
maxAttempts = 3

while (++attempts <= maxAttempts) {
    println("Attempt " + attempts)
    // Process attempt
}

Prefix Return Values

Understanding prefix return behavior:

soul demonstratePrefix() {
    value = 10
    
    // Prefix returns modified value
    returned = ++value      // value = 11, returned = 11
    
    return {
        "returned": returned,
        "final": value
    }
}

result = demonstratePrefix()
println(result.returned)  // 11
println(result.final)     // 11

Prefix in Assignments

Chain prefix operators with assignments:

a = 5
b = 10

// Multiple prefix operations
result = ++a + --b      // a = 6, b = 9, result = 6 + 9 = 15

// Prefix with assignment
c = ++a                 // a = 7, c = 7

Prefix with Different Data Types

Prefix operators work with various types:

// Numeric prefix
intValue = 42
result = ++intValue     // intValue = 43, result = 43

// Boolean prefix (logical NOT)
boolValue = true
result = !boolValue     // result = false

// String prefix (if supported)
// Note: increment/decrement typically work only with numbers

Prefix in Complex Expressions

Use prefix operators in complex calculations:

// Array index manipulation
matrix = [[1, 2], [3, 4], [5, 6]]
row = -1
col = 0

// Navigate matrix with prefix
value1 = matrix[++row][col]     // row = 0, value1 = 1
value2 = matrix[row][++col]     // col = 1, value2 = 2

Prefix Side Effects

Be aware of prefix side effects:

// Side effect awareness
counter = 0

// This modifies counter twice
result = ++counter + ++counter  // counter = 1, then 2, result = 1 + 2 = 3

// Clearer alternative
counter = 0
first = ++counter
second = ++counter
result = first + second         // result = 1 + 2 = 3

Prefix in Iterators

Use prefix operators for custom iterators:

sanctuary Counter {
    soul __genesis__(start) {
        this.value = start
    }
    
    soul preIncrement() {
        return ++this.value
    }
    
    soul preDecrement() {
        return --this.value
    }
}

counter = Counter.new(10)
println(counter.preIncrement())     // 11
println(counter.preIncrement())     // 12
println(counter.preDecrement())     // 11
println(counter.preDecrement())     // 10

Prefix Performance Considerations

Understanding prefix performance:

// Prefix can be more efficient than postfix
value = 1000000
for (i = 0; i < value; ++i) {
    // ++i doesn't need temporary storage
    processItem(i)
}

// Postfix creates temporary values
for (i = 0; i < value; i++) {
    // i++ creates a temporary value
    processItem(i)
}

Prefix Error Handling

Handle prefix operations safely:

soul safePreIncrement(obj, property) {
    if (obj == null || property == null) {
        return null
    }
    
    if (typeof obj[property] != "number") {
        return null
    }
    
    try {
        return ++obj[property]
    } catch (error) {
        println("Error incrementing property: " + error)
        return null
    }
}

// Usage
stats = {"count": 5}
newValue = safePreIncrement(stats, "count")  // newValue = 6, stats.count = 6

Prefix with Logical Operations

Combine prefix with logical operations:

// Logical NOT combinations
isValid = true
isActive = false

// Complex logical expressions
shouldProcess = !isValid || !isActive     // false || true = true
shouldSkip = !(isValid && isActive)       // !(true && false) = true

// Prefix in conditions
if (!user.isActive || !user.hasPermission) {
    println("Access denied")
}

Best Practices

Use prefix for efficiency: Prefer ++i over i++ when the return value doesn’t matter
Keep expressions simple: Avoid complex expressions with multiple prefix operators
Use meaningful variable names: Make prefix operations clear
Be consistent: Choose either prefix or postfix style and stick with it
Consider readability: Sometimes regular assignment is clearer

// Good - clear prefix usage
for (i = 0; i < items.length(); ++i) {
    processItem(items[i])
}

// Good - logical NOT usage
if (!user.isActive) {
    return "User is inactive"
}

// Avoid - confusing prefix usage
result = ++array[++index] + ++array[++index]

// Better - clear and explicit
index++
first = ++array[index]
second = ++array[index]
result = first + second

// Best - most readable
index += 2
result = array[index] + array[index + 1]

Common Pitfalls

Avoid these common prefix mistakes:

// Mistake 1: Multiple prefix on same variable
a = 5
result = ++a + ++a      // Undefined behavior, avoid this

// Mistake 2: Prefix in function calls with same variable
counter = 0
process(++counter, ++counter)  // Order of evaluation unclear

// Mistake 3: Mixing prefix and postfix
result = ++counter + counter++  // Confusing, avoid this

// Safe alternatives
counter = 0
first = ++counter
second = ++counter
process(first, second)

Prefix Operator Summary

Operator	Description	Example
`++var`	Pre-increment	`++counter`
`--var`	Pre-decrement	`--counter`
`-var`	Unary minus	`-value`
`!var`	Logical NOT	`!condition`

Prefix operators are essential tools for modifying variables and evaluating expressions before their values are used. Use them wisely to write efficient and readable code.

CLI Usage

Modules

Syntaxes

prefix

prefix

Basic Prefix Operators

Prefix vs Postfix

Unary Negation

Logical NOT

Prefix in Expressions

Prefix in Loops

Prefix with Array Processing

Prefix in Function Calls

Prefix with Object Properties

Prefix in Conditional Statements

Prefix Return Values

Prefix in Assignments

Prefix with Different Data Types

Prefix in Complex Expressions

Prefix Side Effects

Prefix in Iterators

Prefix Performance Considerations

Prefix Error Handling

Prefix with Logical Operations

Best Practices

Common Pitfalls

Prefix Operator Summary

CLI Usage

Modules

Syntaxes

​prefix

​Basic Prefix Operators

​Prefix vs Postfix

​Unary Negation

​Logical NOT

​Prefix in Expressions

​Prefix in Loops

​Prefix with Array Processing

​Prefix in Function Calls

​Prefix with Object Properties

​Prefix in Conditional Statements

​Prefix Return Values

​Prefix in Assignments

​Prefix with Different Data Types

​Prefix in Complex Expressions

​Prefix Side Effects

​Prefix in Iterators

​Prefix Performance Considerations

​Prefix Error Handling

​Prefix with Logical Operations

​Best Practices

​Common Pitfalls

​Prefix Operator Summary

prefix

Basic Prefix Operators

Prefix vs Postfix

Unary Negation

Logical NOT

Prefix in Expressions

Prefix in Loops

Prefix with Array Processing

Prefix in Function Calls

Prefix with Object Properties

Prefix in Conditional Statements

Prefix Return Values

Prefix in Assignments

Prefix with Different Data Types

Prefix in Complex Expressions

Prefix Side Effects

Prefix in Iterators

Prefix Performance Considerations

Prefix Error Handling

Prefix with Logical Operations

Best Practices

Common Pitfalls

Prefix Operator Summary