local errors = require'errors'

This is an API that adds structured exceptions to Lua. Exceptions, like coroutines are not used very frequently in Lua because they solve cross-cutting concerns(*) that don’t appear very often in code. But when they do appear, these devices are invaluable code decluttering tools.

Structured exceptions are an enhancement over string exceptions that enable selective catching and allow providing a context for the failure to help with recovery or logging.

(*) Coroutines address the problem of inversion-of-control head-on. Exceptions address the problem of recoverable failure head-on, so they’re most useful in network I/O contexts.

API

errors.error	base class for errors
errors.errortype([classname], [super]) -> eclass	create an error class
eclass(...) -> e	create an error object
errors.new(classname, [e], ... | e) -> e	create/wrap/pass-through an error object
errors.is(v[, classes]) -> t|f	check an error object type
errors.raise(classname,[e],... | e)	(create and) raise an error
errors.catch(classes, f, ...) -> t,... | f,e	pcall f and catch errors
errors.pcall(f, ...) -> ...	pcall that stores traceback in e.traceback
errors.check(v, ...) -> v | raise(...)	assert with specifying an error class
errors.protect(classes, f) -> protected_f	turn raising f into a nil,e function
eclass:__call(...) -> e	error class constructor
eclass:__tostring() -> s	to make error(e) work
e.message	formatted error message
e.traceback	traceback at error site

In the API classes can be given as 'classname1 ...' or {class1->true}. When in table form, you must include all the superclasses in the table as they are not added automatically!

Last updated: 4 months ago | Edit on GitHub