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postfix

Postfix operators in Soul are operators that are applied after their operands. The most common postfix operators are increment (++) and decrement (--), which modify variables after their current value has been used.

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Basic Postfix Operators

The primary postfix operators modify numeric variables: 
counter = 5

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

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

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Postfix vs Prefix

Understanding the difference between postfix and prefix operators: 
// Postfix: use current value, then modify
a = 5
result = a++            // result = 5, a = 6

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

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Postfix in Expressions

Use postfix operators within larger expressions: 
counter = 10
index = 0

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

// Postfix in calculations
total = counter++ * 2   // total = 20, counter = 11

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Postfix in Loops

Common usage in loop constructs: 
// For loop with postfix increment
for (i = 0; i < 10; i++) {
    println("Iteration: " + i)
}

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

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Postfix with Array Processing

Use postfix operators for array manipulation: 
items = [10, 20, 30, 40, 50]
index = 0

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

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

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Postfix in Function Calls

Use postfix operators in function arguments: 
counter = 0

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

// Function calls with postfix
logWithIncrement(counter++)  // Log #0, counter = 1
logWithIncrement(counter++)  // Log #1, counter = 2
logWithIncrement(counter++)  // Log #2, counter = 3

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Postfix with Object Properties

Apply postfix operators to object properties: 
stats = {
    "hits": 0,
    "misses": 0,
    "total": 0
}

// Postfix on object properties
oldHits = stats.hits++      // Get current hits, then increment
stats.total++               // Increment total count

println("Previous hits: " + oldHits)  // Previous hits: 0
println("Current hits: " + stats.hits)  // Current hits: 1

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Postfix in Conditional Statements

Use postfix operators in conditions: 
attempts = 0
maxAttempts = 3

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

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Postfix Return Values

Understanding postfix return behavior: 
soul demonstratePostfix() {
    value = 10
    
    // Postfix returns original value
    returned = value++      // returned = 10, value = 11
    
    return {
        "returned": returned,
        "final": value
    }
}

result = demonstratePostfix()
println(result.returned)  // 10
println(result.final)     // 11

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Postfix in Assignments

Chain postfix operators with assignments: 
a = 5
b = 10

// Multiple postfix operations
result = a++ + b--      // result = 5 + 10 = 15
                        // a = 6, b = 9

// Postfix with assignment
c = a++                 // c = 6, a = 7

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Postfix with Different Data Types

Postfix operators work with various numeric types: 
// Integer postfix
intValue = 42
result = intValue++     // result = 42, intValue = 43

// Float postfix
floatValue = 3.14
result = floatValue++   // result = 3.14, floatValue = 4.14

// Note: Postfix typically works only with numeric types

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Postfix in Complex Expressions

Use postfix operators in complex calculations: 
// Array index manipulation
matrix = [[1, 2], [3, 4], [5, 6]]
row = 0
col = 0

// Navigate matrix with postfix
value1 = matrix[row++][col]     // value1 = 1, row = 1
value2 = matrix[row][col++]     // value2 = 3, col = 1
value3 = matrix[row][col]       // value3 = 4

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Postfix Side Effects

Be aware of postfix side effects: 
// Side effect awareness
counter = 0

// This modifies counter twice
result = counter++ + counter++  // result = 0 + 1 = 1, counter = 2

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

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Postfix in Iterators

Use postfix operators for custom iterators: 
sanctuary Counter {
    soul __genesis__(start) {
        this.value = start
    }
    
    soul next() {
        return this.value++
    }
    
    soul previous() {
        return this.value--
    }
}

counter = Counter.new(10)
println(counter.next())     // 10
println(counter.next())     // 11
println(counter.previous()) // 12
println(counter.previous()) // 11

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Postfix Performance Considerations

Understanding postfix performance: 
// Postfix creates temporary values
value = 1000000
for (i = 0; i < value; i++) {
    // Each i++ creates a temporary value
    processItem(i)
}

// Sometimes prefix is more efficient
for (i = 0; i < value; ++i) {
    // ++i doesn't need temporary storage
    processItem(i)
}

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Postfix Error Handling

Handle postfix operations safely: 
soul safeIncrement(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}
oldValue = safeIncrement(stats, "count")  // oldValue = 5, stats.count = 6

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Best Practices

  1. Use sparingly: Postfix operators can make code harder to read
  2. Avoid in complex expressions: Split complex expressions for clarity
  3. Be aware of side effects: Understand when variables are modified
  4. Use meaningful variable names: Make postfix operations clear
  5. Consider alternatives: Sometimes regular assignment is clearer
// Good - clear postfix usage
for (i = 0; i < items.length(); i++) {
    processItem(items[i])
}

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

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

// Best - most readable
result = array[index] + array[index + 1] + array[index + 2]
index += 3

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Common Pitfalls

Avoid these common postfix mistakes: 
// Mistake 1: Multiple postfix on same variable
a = 5
result = a++ + a++      // Undefined behavior, avoid this

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

// Mistake 3: Postfix in complex expressions
array[index++] = array[index++]  // Dangerous, avoid this

// Safe alternatives
counter = 0
first = counter++
second = counter++
process(first, second)
Postfix operators are powerful tools for incrementing and decrementing variables, but they should be used judiciously to maintain code clarity and avoid subtle bugs.
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