|
<condition> | (<any>) | C |
|
default-handler | (x|<condition> => <fun>) | G |
|
| called if no appropriate handler is in force. | |
|
default-handler-description | (c|<condition> => <str>) | G |
|
| return a string describing an anonymous handler for this type of
condition. | |
|
build-condition-interactively | (type|<condition> in out
=> <condition>) | G |
|
| construct a condition of the specified type and interactively prompt
the user to fill in any important props. Called by the debugger.
Methods should call next-method to build the condition, then set the
props for their own class. | |
|
sig | (x|<condition> args|...) | G |
|
| signals a condition with optional arguments args. | |
|
<simple-condition> | (<condition>) | C |
|
| a condition consisting of a msg message and arguments. | |
|
condition-message | (x|<simple-condition> => <str>) | P |
|
| returns msg string. | |
|
condition-arguments | (x|<simple-condition> => <lst>) | P |
|
| returns msg string arguments. | |
|
<serious-condition> | (<condition>) | C |
|
| a condition that can not be safely ignored. | |
|
<error> | (<serious-condition>) | C |
|
| a condition that indicates something is invalid about the program. | |
|
error | (x|<any> args|...) | G |
|
| signals an error. | |
|
error | (x|<str> args|...) | M |
|
| signals a simple error. | |
|
<simple-error> | (<error> <simple-condition>) | C |
|
| an error that consists of a msg message and arguments. | |
|
<restart> | (<condition>) | C |
|
| used for restarting a computation. | |
|
<handler> | (<any>) | C |
|
| object used for handling a signaled condition. | |
|
handler-function | (x|<handler> => <fun>) | G |
|
fab-handler | (x|<fun> => <handler>) | G |
|
| creates a handler from a handler function. | |
|
handler-matches? | (x|<handler> y|<condition> => <log>) | G |
|
| protocol for determining whether a handler handles a particular
condition. | |
|
TRY | (TRY ,try-options ,handler ,@body) | S |
|
| installs ,handler as a condition handler for the
duration of (SEQ ,@body), using the instructions provided
by ,try-options.
,try-options should either be the name of the condition type to
handle, or a ,try-option-list with zero or more of the
following options:
- (TYPE ,expr) =>
An expression returning the type of condition to handle.
- (TEST ,@body) => Code
which returns #t if the condition is applicable,
and #f otherwise. This may be called at arbitrary times
by the runtime, so it shouldn't do anything too alarming.
- (DESCRIPTION ,message ,@arguments) =>
A human-readable description of this handler. Used by the debugger.
The handler function should take two arguments: the ,condition to be
handled, and a ,resume function. if a matching condition is signaled
then the handler function is called with the signaled condition and a
resume function to be called if the handler wants to return a value to be
used as the result of the signaling SIG call. the handler has three
possibilities: (1) it can handle the condition by taking an exit using
ESC, (2) it can resume to the original SIG call using the
resume function
called with the value to be returned, or (3) it can do neither, that is,
it can choose not to handle the condition by just falling through to the
end of the handler (cf., Dylan's BLOCK/EXCEPTION
and LET HANDLER) and the next available handler will be invoked.
Note that GOO does not unwind the stack before calling
handlers! | |
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