Exception Handling

Kronos provides try/catch/finally blocks for handling errors gracefully.

Basic Exception Handling

Try-Catch

try:
    set content to call read_file with "config.txt"
    print content
catch error:
    print f"Error occurred: {error}"

Try-Catch-Finally

The finally block always executes, whether an exception occurs or not:

try:
    set content to call read_file with "config.txt"
    print content
catch error:
    print f"Failed to read file: {error}"
finally:
    print "Cleanup complete"

Raising Exceptions

You can raise exceptions using the raise keyword:

function divide with a, b:
    if b is equal 0:
        raise "Division by zero is not allowed"
    return a divided by b

try:
    set result to call divide with 10, 0
    print result
catch error:
    print f"Error: {error}"  # Prints: Error: Division by zero is not allowed

Raising with Exception Types

You can specify an exception type:

try:
    raise ValueError "Invalid input value"
catch ValueError as e:
    print f"ValueError: {e}"
catch error:
    print f"Other error: {error}"

Catching Specific Exceptions

You can catch specific exception types:

try:
    raise RuntimeError "Something went wrong"
catch RuntimeError as e:
    print f"Runtime error: {e}"
catch error:
    print f"Generic error: {error}"

Examples

File Operations with Error Handling

try:
    set content to call read_file with "data.txt"
    print content
catch error:
    print f"Could not read file: {error}"
    # Fallback behavior
    set content to "default content"

Input Validation

function process_age with age_str:
    try:
        set age to call to_number with age_str
        if age is less than 0:
            raise "Age cannot be negative"
        if age is greater than 150:
            raise "Age seems invalid"
        return age
    catch error:
        print f"Invalid age: {error}"
        return null

set age1 to call process_age with "25"
set age2 to call process_age with "-5"
set age3 to call process_age with "abc"

Resource Cleanup

try:
    set data to call read_file with "important.txt"
    # Process data...
    print data
catch error:
    print f"Error processing file: {error}"
finally:
    # Always cleanup, even if error occurred
    print "Closing file handles..."
    # Cleanup code here

Nested Exception Handling

function risky_operation with value:
    if value is less than 0:
        raise "Value must be positive"
    return value times 2

try:
    set result to call risky_operation with -5
    print result
catch error:
    print f"Operation failed: {error}"
    # Try alternative
    try:
        set result to call risky_operation with 10
        print result
    catch error2:
        print f"Alternative also failed: {error2}"

Exception Handling

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