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|
----
-- Language error and traceback.
--
-- @classmod Error
unpack or= table.unpack
class Error
--- members
-- @section members
--- append a traceback frame.
--
-- `where` should denote where the Error occured and fit grammatically to
-- complete the sentence `"{error} occured while {where}"`
--
-- @tparam string where
add_frame: (where) => @trace ..= "\n while #{where}"
__tostring: =>
str = "#{@kind} error: #{@message}"
if @detail
str ..= "\n#{@detail}"
if @trace
str ..= @trace
str
--- static functions
-- @section static
--- create a new Error.
--
-- `kind` should be one of:
--
-- - `'reference'`: error concerning symbol resolution
-- - `'argument'`: error concerning Op argument matching
-- - `'implementation'`: error in the Lua/MoonScript implementation of alive.
-- Should not occur in normal operation, and constitutes a bug.
--
-- @classmethod
-- @tparam string kind
-- @tparam string message
-- @tparam ?string detail
new: (@kind, @message, @detail) =>
@trace = ''
handler = (err) ->
if err.__class == Error
err
else
trace = debug.traceback "Lua error below:", 2
Error 'implementation', err, trace
--- Wrap function errors in a traceback frame.
--
-- Execute `fn(...)`, and turn any error thrown as a result into an
-- `Error` instance, before re-throwing it.
--
-- When `Error` instances are caught, `frame` is added to the traceback.
-- All other error values are turned into `'implementation'` Errors.
--
-- @tparam string frame
-- @tparam function fn
@wrap: (frame, fn, ...) ->
results = { xpcall fn, handler, ... }
ok = table.remove results, 1
if ok
unpack results
else
results[1]\add_frame frame if frame
error results[1]
--- Capture and wrap function errors in traceback frame.
--
-- Execute `fn(...)`, and turn any error thrown as a result into an
-- `Error` instance, before re-throwing it.
--
-- When `Error` instances are caught, `frame` is added to the traceback.
-- All other error values are turned into `'implementation'` Errors.
--
-- @tparam ?string frame
-- @tparam function fn
-- @treturn boolean `ok` true if exeuction suceeded without errors
-- @treturn Error|any `error_or_results` the `Error` instance or results
@try: (frame, fn, ...) ->
results = { xpcall fn, handler, ... }
ok = table.remove results, 1
if ok
ok, unpack results
else
results[1]\add_frame frame if frame
ok, unpack results
{
:Error
}
|
