Documentation Index
Fetch the complete documentation index at: https://soul-lang.com/llms.txt
Use this file to discover all available pages before exploring further.
switch
The switch statement provides a way to execute different code blocks based on the value of an expression. It’s a cleaner alternative to long chains of if-else statements when comparing a single value against multiple possibilities.
Basic Switch Statement
Compare a value against multiple cases:
command = "start"
switch (command) {
case "start":
println("Starting application")
break
case "stop":
println("Stopping application")
break
case "restart":
println("Restarting application")
break
default:
println("Unknown command")
}
Switch with Multiple Values per Case
Match multiple values in a single case:
dayOfWeek = "saturday"
switch (dayOfWeek) {
case "saturday", "sunday":
println("It's weekend!")
break
case "monday", "tuesday", "wednesday", "thursday", "friday":
println("It's a weekday")
break
default:
println("Invalid day")
}
Switch with Different Data Types
Switch works with various data types:
value = 42
switch (value) {
case 0:
println("Zero")
break
case 1, 2, 3:
println("Small number")
break
case "hello":
println("String greeting")
break
case true:
println("Boolean true")
break
case null:
println("Null value")
break
default:
println("Other value: " + value)
}
Switch with Break Statements
Use break to prevent fall-through:
grade = "B"
switch (grade) {
case "A":
println("Excellent!")
break // Prevents fall-through
case "B":
println("Good job!")
break
case "C":
println("Average")
break
case "D":
println("Below average")
break
case "F":
println("Failed")
break
default:
println("Invalid grade")
}
Switch with Fall-through
Intentional fall-through without break:
userLevel = 3
switch (userLevel) {
case 1:
println("Level 1 access granted")
// Falls through to level 2
case 2:
println("Level 2 access granted")
// Falls through to level 3
case 3:
println("Level 3 access granted")
break
default:
println("No access")
}
// Output for level 3: all three access messages
Switch with Complex Cases
Each case can contain complex logic:
action = "process"
switch (action) {
case "process":
println("Processing data...")
// Complex processing logic
data = loadData()
if (data != null) {
result = transformData(data)
saveResult(result)
println("Processing complete")
} else {
println("No data to process")
}
break
case "cleanup":
println("Cleaning up...")
// Cleanup logic
clearCache()
closeConnections()
println("Cleanup complete")
break
case "backup":
println("Creating backup...")
// Backup logic
timestamp = getCurrentTime()
backupFile = "backup_" + timestamp + ".sql"
createBackup(backupFile)
println("Backup created: " + backupFile)
break
default:
println("Unknown action: " + action)
}
Switch with Function Calls
Use function calls in switch cases:
userRole = "admin"
switch (userRole) {
case "admin":
grantAdminAccess()
setupAdminDashboard()
logAdminLogin()
break
case "user":
grantUserAccess()
setupUserDashboard()
logUserLogin()
break
case "guest":
grantGuestAccess()
setupGuestView()
logGuestVisit()
break
default:
denyAccess()
logInvalidRole(userRole)
}
Switch with Variable Assignments
Assign values based on switch cases:
status = "active"
permissions = []
message = ""
switch (status) {
case "active":
permissions = ["read", "write", "execute"]
message = "Full access granted"
break
case "inactive":
permissions = ["read"]
message = "Limited access"
break
case "suspended":
permissions = []
message = "Access suspended"
break
default:
permissions = []
message = "Invalid status"
}
Switch with Return Statements
Use switch in functions with return:
soul getHttpStatusMessage(code) {
switch (code) {
case 200:
return "OK"
case 201:
return "Created"
case 400:
return "Bad Request"
case 401:
return "Unauthorized"
case 403:
return "Forbidden"
case 404:
return "Not Found"
case 500:
return "Internal Server Error"
default:
return "Unknown Status Code"
}
}
message = getHttpStatusMessage(404) // "Not Found"
Nested Switch Statements
Switch statements can be nested:
category = "user"
operation = "create"
switch (category) {
case "user":
switch (operation) {
case "create":
println("Creating user")
createUser()
break
case "update":
println("Updating user")
updateUser()
break
case "delete":
println("Deleting user")
deleteUser()
break
default:
println("Unknown user operation")
}
break
case "product":
switch (operation) {
case "create":
println("Creating product")
createProduct()
break
case "update":
println("Updating product")
updateProduct()
break
case "delete":
println("Deleting product")
deleteProduct()
break
default:
println("Unknown product operation")
}
break
default:
println("Unknown category")
}
Switch with Expressions
Use expressions in switch values:
score = 85
switch (true) {
case score >= 90:
println("Grade: A")
break
case score >= 80:
println("Grade: B")
break
case score >= 70:
println("Grade: C")
break
case score >= 60:
println("Grade: D")
break
default:
println("Grade: F")
}
Switch with Error Handling
Handle errors in switch cases:
errorCode = getErrorCode()
switch (errorCode) {
case 0:
println("No error")
break
case 1:
println("File not found")
handleFileNotFound()
break
case 2:
println("Permission denied")
handlePermissionDenied()
break
case 3:
println("Network error")
handleNetworkError()
break
default:
println("Unknown error: " + errorCode)
handleUnknownError(errorCode)
}
// Good - most common cases first
switch (requestType) {
case "GET": // Most common
handleGet()
break
case "POST": // Second most common
handlePost()
break
case "PUT":
handlePut()
break
case "DELETE":
handleDelete()
break
default:
handleUnknown()
}
// Use switch instead of multiple if-else
soul getFileType(extension) {
switch (extension.toLowerCase()) {
case "jpg", "jpeg", "png", "gif":
return "image"
case "mp4", "avi", "mov":
return "video"
case "mp3", "wav", "flac":
return "audio"
case "pdf", "doc", "docx":
return "document"
default:
return "unknown"
}
}
Switch vs If-Else
When to use switch vs if-else:
// Use switch for multiple exact matches
switch (status) {
case "active": return "User is active"
case "inactive": return "User is inactive"
case "suspended": return "User is suspended"
default: return "Unknown status"
}
// Use if-else for ranges or complex conditions
if (age < 18) {
return "Minor"
} else if (age < 65) {
return "Adult"
} else {
return "Senior"
}
Best Practices
- Always use break: Prevent unintended fall-through
- Include default case: Handle unexpected values
- Order cases logically: Most common cases first
- Keep cases simple: Complex logic should be in functions
- Use meaningful case values: Make switch purpose clear
// Good - clear and well-structured
soul processCommand(command) {
switch (command.toLowerCase()) {
case "start":
case "begin":
case "run":
return startApplication()
case "stop":
case "end":
case "quit":
return stopApplication()
case "pause":
case "suspend":
return pauseApplication()
case "resume":
case "continue":
return resumeApplication()
default:
return {
success: false,
error: "Unknown command: " + command
}
}
}
// Better - with validation
soul processCommand(command) {
if (command == null || command == "") {
return {
success: false,
error: "Command cannot be empty"
}
}
normalizedCommand = command.toLowerCase().trim()
switch (normalizedCommand) {
case "start":
case "begin":
case "run":
return startApplication()
case "stop":
case "end":
case "quit":
return stopApplication()
case "help":
case "?":
return showHelp()
default:
return {
success: false,
error: "Unknown command: " + command,
suggestion: "Try 'help' for available commands"
}
}
}
