hg/stx-libbasic: Query.st@cec93c942c14 (annotated)

4464 cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	1	'From Smalltalk/X, Version:3.5.3 on 26-jul-1999 at 00:02:41' !
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	2
4446 4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	3	Exception subclass:#Query
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	4	instanceVariableNames:''
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	5	classVariableNames:''
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	6	poolDictionaries:''
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	7	category:'Kernel-Exceptions'
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	8	!
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	9
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	10	!Query class methodsFor:'documentation'!
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	11
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	12	documentation
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	13	"
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	14	Query ist an abstract superclass of all query exceptions in the system
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	15
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	16	[author:]
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	17	Stefan Vogel
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	18
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	19	[see also:]
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	20	Signal QuerySignal
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	21	"
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	22
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	23	!
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	24
4464 cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	25	examples
4446 4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	26	"
4464 cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	27	an up-query from a deeply nested operation to a higher level:
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	28	[exBegin]
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	29	\|zero\|
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	30
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	31	zero := 0.
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	32	Query handle:[:ex \|
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	33	Transcript showCR:'query'.
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	34	ex proceedWith:true
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	35	] do:[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	36	'nesting'.
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	37	[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	38	[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	39	Object errorSignal handle:[:ex \|
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	40	Transcript showCR:'some error: ' , ex errorString.
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	41	ex proceed
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	42	] do:[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	43	[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	44	1 // zero. 'an error which is caught in the handler'.
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	45	(Query query) == true ifTrue:[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	46	Transcript showCR:'query says: ok'.
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	47	] ifFalse:[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	48	Transcript showCR:'query says: no'
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	49	]
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	50	] value
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	51	]
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	52	] value
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	53	] value
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	54	]
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	55	[exEnd]
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	56	for lazy typists, a more compact interface is also provided
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	57	(which is also easier to read):
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	58	[exBegin]
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	59	Query answer:true do:[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	60	'nesting'.
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	61	[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	62	[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	63	(Query query) == true ifTrue:[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	64	Transcript showCR:'query says: ok'.
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	65	] ifFalse:[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	66	Transcript showCR:'query says: no'
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	67	]
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	68	] value
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	69	] value
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	70	]
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	71	[exEnd]
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	72	an up-query from a deeply nested operation, for which there
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	73	is no handler:
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	74	(notice, this would not work with normal signals, which would raise
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	75	another unhandled exception-exception;
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	76	also notice the == check #raise's return value being true,
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	77	instead of a simple ifTrue; this handles a nil-value from
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	78	the unhandled query)
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	79	[exBegin]
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	80	\|zero\|
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	81
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	82	zero := 0.
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	83	[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	84	'nesting'.
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	85	[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	86	[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	87	Object errorSignal handle:[:ex \|
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	88	Transcript showCR:'some error: ' , ex errorString.
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	89	ex proceed
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	90	] do:[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	91	[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	92	1 // zero. 'an error which is caught in the handler'.
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	93	(Query raise) == true ifTrue:[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	94	Transcript showCR:'query says: ok'.
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	95	] ifFalse:[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	96	Transcript showCR:'query says: no'
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	97	]
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	98	] value
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	99	]
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	100	] value
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	101	] value
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	102	] value
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	103	[exEnd]
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	104	counter-example, just to show that things would not work this way
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	105	with regular signals:
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	106	[exBegin]
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	107	\|signal\|
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	108
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	109	signal := Signal new.
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	110	'nesting deeply'.
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	111	[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	112	[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	113	[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	114	[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	115	[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	116	(signal raise) == true ifTrue:[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	117	Transcript showCR:'query says: ok'.
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	118	] ifFalse:[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	119	Transcript showCR:'query says: no'
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	120	]
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	121	] value
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	122	] value
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	123	] value
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	124	] value
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	125	] value
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	126	[exEnd]
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	127
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	128	except, by handling the unhandled exception
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	129	(but we think, that querySignals are easier to use and
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	130	better document the intent):
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	131	[exBegin]
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	132	\|signal\|
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	133
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	134	signal := Signal new.
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	135	'nesting deeply'.
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	136	[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	137	[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	138	[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	139	[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	140	[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	141	Signal noHandlerSignal handle:[:ex \|
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	142	ex proceedWith:nil
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	143	] do:[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	144	(signal raise) == true ifTrue:[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	145	Transcript showCR:'query says: ok'.
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	146	] ifFalse:[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	147	Transcript showCR:'query says: no'
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	148	]
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	149	]
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	150	] value
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	151	] value
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	152	] value
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	153	] value
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	154	] value
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	155	[exEnd]
4446 4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	156	"
4464 cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	157
4446 4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	158	!
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	159
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	160	history
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	161	"Created: / 23.7.1999 / 14:16:16 / stefan"
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	162	! !
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	163
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	164	!Query class methodsFor:'answering queries'!
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	165
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	166	answer:someAnswer do:aBlock
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	167	"evaluate the argument, aBlock.
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	168	If the receiver is queried during evaluation, answer with someAnswer.
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	169	This is a wrapper for #handle:do: for lazy typists; no new functionality."
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	170
4464 cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	171	thisContext markForHandle.
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	172	aBlock value.
4446 4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	173
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	174	"
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	175	Query answer:true do:[
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	176	Transcript showCR:'query answers: ' , (Query query printString).
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	177	]
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	178	"
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	179
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	180	"
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	181	Query answer:false do:[
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	182	Transcript showCR:'first query answers: ' , (Query query printString).
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	183	Query answer:true do:[
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	184	Transcript showCR:'second query answers: ' , (Query query printString).
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	185	]
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	186	]
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	187	"
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	188
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	189	"Created: / 10.7.1996 / 15:08:20 / cg"
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	190	"Modified: / 14.10.1996 / 16:59:18 / cg"
4464 cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	191	"Modified: / 25.7.1999 / 23:12:19 / stefan"
4446 4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	192	! !
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	193
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	194	!Query class methodsFor:'queries'!
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	195
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	196	accepts:aSignal
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	197	"return true, if the receiver accepts the argument, aSignal.
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	198	(i.e. the receiver is aSignal or a parent of it). False otherwise."
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	199
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	200	\|s\|
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	201
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	202	aSignal isQuerySignal ifFalse:[^ false].
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	203
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	204	s := aSignal.
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	205	[s notNil] whileTrue:[
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	206	self == s ifTrue:[^ true].
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	207	s := s parent
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	208	].
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	209	^ false
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	210
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	211	"Modified: / 22.3.1999 / 12:45:32 / stefan"
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	212	"Created: / 23.7.1999 / 15:18:00 / stefan"
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	213	!
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	214
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	215	defaultAnswer
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	216	"Return the default answer to the Query. This method is called,
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	217	if nobody catches the signal.
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	218
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	219	Subclasses may redefine this method."
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	220
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	221	"Calling raiseRequest here will execute the exception's action method"
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	222
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	223	^ super raiseRequest
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	224
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	225	"Created: / 23.7.1999 / 15:16:03 / stefan"
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	226	!
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	227
4464 cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	228	handlerForSignal:signal context:theContext originator:originator
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	229	"answer the handler block for the signal from originator.
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	230	The block is retrieved from aContext.
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	231	Answer nil if the signal is not handled"
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	232
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	233	\|arg\|
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	234
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	235	theContext selector == #'answer:do:' ifTrue:[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	236	(self accepts:signal) ifTrue:[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	237	arg := theContext argAt:1.
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	238	^ [:ex\| ex proceedWith:arg].
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	239	]
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	240	] ifFalse:[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	241	^ super handlerForSignal:signal context:theContext originator:originator.
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	242	].
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	243
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	244	^ nil
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	245
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	246	"Created: / 25.7.1999 / 23:11:55 / stefan"
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	247	!
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	248
4446 4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	249	isQuerySignal
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	250
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	251	^ true
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	252
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	253	"Created: / 23.7.1999 / 14:59:50 / stefan"
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	254	!
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	255
4464 cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	256	query
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	257	"raise the query - return the handlers value, or the default
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	258	value, if there is no handler.
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	259	Invoking the handler is exactly the functionality of Signal>>raiseRequest,
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	260	but we can do it faster here."
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	261
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	262	\|con s\|
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	263
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	264	con := thisContext sender.
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	265	[con notNil] whileTrue:[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	266	con := con findSpecialHandle:true raise:true.
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	267	con notNil ifTrue:[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	268	(con selector == #answer:do:) ifFalse:[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	269	^ super raiseRequest
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	270	].
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	271	(s := con receiver) == self ifTrue:[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	272	^ con argAt:1
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	273	] ifFalse:[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	274	(s accepts:self) ifTrue:[
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	275	^ super raiseRequest
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	276	]
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	277	]
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	278	]
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	279	].
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	280	"/ no handler found - return the default value
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	281	^ self defaultAnswer
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	282
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	283	"Modified: / 15.6.1998 / 21:27:37 / cg"
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	284	"Modified: / 25.7.1999 / 23:15:16 / stefan"
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	285	!
cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	286
4446 4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	287	raise
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	288	"QuerySignals are proceedable by definition,
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	289	so they should be raised with #query or #raiseRequest"
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	290
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	291	^ self shouldNotImplement
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	292
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	293	"Created: / 23.7.1999 / 15:19:17 / stefan"
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	294	!
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	295
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	296	raiseRequest
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	297	"redefined to use #query"
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	298
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	299	^ self query
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	300
4464 cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	301	"Created: / 25.7.1999 / 23:25:59 / stefan"
4446 4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	302	! !
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	303
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	304	!Query methodsFor:'default actions'!
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	305
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	306	action
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	307	"the default action is to return the default value.
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	308	Subclasses may redefine this"
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	309
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	310	^ nil
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	311
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	312	"Modified: / 23.7.1999 / 15:13:34 / stefan"
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	313	! !
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	314
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	315	!Query class methodsFor:'documentation'!
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	316
4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	317	version
4464 cec93c942c14 Use context flag for exception handling instead of searching for Stefan Vogel <sv@exept.de> parents: 4446 diff changeset	318	^ '$Header: /cvs/stx/stx/libbasic/Query.st,v 1.2 1999-07-28 07:53:26 stefan Exp $'
4446 4da4e51fc1ab initial checkin Stefan Vogel <sv@exept.de> parents: diff changeset	319	! !

author	Stefan Vogel <sv@exept.de>
	Wed, 28 Jul 1999 09:53:29 +0200
changeset 4464	cec93c942c14
parent 4446	4da4e51fc1ab
child 4466	9cba6f4ecec4
permissions	-rw-r--r--