Try

The syntax for Lua error handling in a common form.

try
  func 1, 2, 3
catch err
  print yue.traceback err

success, result = try
  func 1, 2, 3
catch err
  yue.traceback err

try func 1, 2, 3
catch err
  print yue.traceback err

success, result = try func 1, 2, 3

try
  print "trying"
  func 1, 2, 3

-- working with if assignment pattern
if success, result := try func 1, 2, 3
catch err
    print yue.traceback err
  print result

try
  func 1, 2, 3
catch err
  print yue.traceback err

success, result = try
  func 1, 2, 3
catch err
  yue.traceback err

try func 1, 2, 3
catch err
  print yue.traceback err

success, result = try func 1, 2, 3

try
  print "trying"
  func 1, 2, 3

-- working with if assignment pattern
if success, result := try func 1, 2, 3
catch err
    print yue.traceback err
  print result

Try?

try? is a simplified use for error handling syntax that omit the boolean status from the try statement, and it will return the result from the try block when success, return nil instead of error object otherwise.

a, b, c = try? func!

-- with nil coalescing operator
a = (try? func!) ?? "default"

-- as function argument
f try? func!

-- with catch block
f try?
  print 123
  func!
catch e
  print e
  e

a, b, c = try? func!

-- with nil coalescing operator
a = (try? func!) ?? "default"

-- as function argument
f try? func!

-- with catch block
f try?
  print 123
  func!
catch e
  print e
  e