[stringtemplate-interest] handling of arrays
Terence Parr
parrt at cs.usfca.edu
Thu Feb 1 12:18:32 PST 2007
is that in java 1.5? I don't it will work in 1.4.
my compiler complained.
ter
On Feb 1, 2007, at 12:18 PM, Nate wrote:
> It does work, I was wrong. In fact, you don't even need a cast...
>
> String[] strings = new String[] {"abc", "def", "ghi"};
> Object[] stringsHiddenByObjectArray = strings;
>
> What I was thinking of was going the other way...
>
> Object[] objects = new Object[] {"jkl", "mno", "pqr"};
> String[] thisDoesntWork = (String[])objects;
>
> -Nate
>
>
> Harry Karadimas wrote:
>> Sorry about the lengthy post, but I checked and found that the
>> cast to
>> (Object[])
>> actually works !
>>
>> Below is a "small" demo class that demonstrates various uses.
>> To make it short, what works is :
>> public static Object convertArrayToList(Object value)
>> {
>> if (value==null || !value.getClass().isArray()) return value;
>> return Arrays.asList((Object[])value);
>> }
>>
>> --------
>>
>> package stringtemplate_test;
>>
>> import java.util.ArrayList;
>> import java.util.Arrays;
>> import java.util.Collection;
>> import java.util.Iterator;
>> import java.util.List;
>>
>> /**
>> * "Lots of Lists", to test various Array to List conversion
>> strategies
>> * @author KARADIMAS
>> */
>> public class Lol
>> {
>> static Object[] myArray = {"A", "B", "C"};
>> static List myList = new ArrayList();
>> static Object[][][] threeLevels = {
>> {
>> {"1.1.1", "1.1.2", "1.1.3"},
>> {"1.2.1", "1.2.2"}
>> },
>> {
>> {"2.1.1"},
>> {"2.2.1", "2.2.2"}
>> },
>> {
>> {"3.1.1", "3.1.2"},
>> {"3.2.1"}
>> },
>> {
>> {myList}
>> },
>> };
>> static int[] myInts = {1,2,3};
>>
>> public static void main(String[] args)
>> {
>> //further init of myList
>> myList.add("X");
>> myList.add(myArray);
>> myList.add("Z");
>> System.out.println("Original list :");
>> printList(threeLevels);
>> System.out.println("convertArrayToList1() :");
>> Object r = convertArrayToList1(threeLevels);
>> printList((List) r);
>> System.out.println("convertArrayToList2() :");
>> r = convertArrayToList2(threeLevels);
>> printList((List) r);
>> System.out.println("convertAllForStUsage() :");
>> r = convertAllAtOnce(threeLevels);
>> printList((List) r);
>> r = convertArrayToList1(myInts);
>> printList(r);
>> }
>>
>> /**
>> * simplest, works ok if called before each use, maybe the best
>> approach if
>> * used in lazy (= just in time) execution.
>> * Note here that Object[][]...[] is an instance of Object[]
>> (and of
>> * Object, incidentally)
>> */
>> public static Object convertArrayToList1(Object value)
>> {
>> if (value==null || !value.getClass().isArray()) return value;
>> return Arrays.asList((Object[])value);
>> }
>>
>> /**
>> * handles sub-arrays recursively at once, but what about arrays
>> inside lists?
>> */
>> public static Object convertArrayToList2(Object value)
>> {
>> if (value==null || !value.getClass().isArray()) return value;
>> Object[] oa1 = (Object[]) value;
>> Object[] oa2 = new Object[oa1.length];
>> System.arraycopy(oa1, 0, oa2, 0, oa1.length);
>> for (int i = 0; i < oa2.length; i++) oa2[i] =
>> convertArrayToList2(oa2[i]);
>> return Arrays.asList(oa2);
>> }
>>
>> /**
>> * More complex method.
>> * Manages both lists and arrays, but what about arrays inside
>> maps, for
>> * example ? And also, why convert now arrays that might never
>> be used ?
>> */
>> public static Object convertAllAtOnce(Object value)
>> {
>> if ( !isListable(value) ) return value;
>> ArrayList res = new ArrayList(); //we always return a new list
>> if (value instanceof List) {
>> //process the list
>> List vList = (List) value;
>> for (Iterator iter = vList.iterator(); iter.hasNext();) {
>> res.add(convertAllAtOnce(iter.next()));
>> }
>> return res;
>> }
>> //it's an array, process its elements
>> Object[] oa = (Object[]) value;
>> for (int i = 0; i < oa.length; i++)
>> res.add(convertAllAtOnce(oa[i]));
>> return res;
>> }
>>
>> /** helper function to clarify code */
>> private static final boolean isListable(Object o)
>> {
>> return (o instanceof List) || (o != null && o.getClass
>> ().isArray());
>> }
>>
>> public static void printList(Object v) { printList("", v); }
>>
>> public static void printList(String indent, Object v) {
>> if (!isListable(v)) {
>> System.out.println(indent+"v="+v);
>> return;
>> }
>> if (v instanceof List) {
>> System.out.println(indent+"(");
>> List lst = (List) v;
>> for (Iterator iter = lst.iterator(); iter.hasNext();) {
>> Object o = (Object) iter.next();
>> printList(indent+" ", o);
>> }
>> System.out.println(indent+")");
>> return;
>> }
>> Object[] oa = (Object[]) v;
>> System.out.println(indent+"[//array");
>> for (int i = 0; i < oa.length; i++) printList(indent+" ", oa
>> [i]);
>> System.out.println(indent+"]//array");
>> }
>>
>> }
>>
>> Harry
>> Karadimas
>> /
>> _____________________________________________________________________
>> _
>> Dr Harry Karadimas Medecin Ingenieur resp. Recherche et
>> Developpement
>> Departement d'Information Hospitalier
>> CHU Henri Mondor 51, av. du Mal de Lattre de Tassigny 94010
>> CRETEIL
>> tel : (00 33 1) 49 81 21 79 fax : (00 33 1) 49 81
>> 27 08
>> secr.: (00 33 1) 49 81 23 82 m.el.:harry.karadimas at hmn.ap-hop-
>> paris.fr
>> /
>>
>>
>> stringtemplate-interest-request at antlr.org a écrit :
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>>>
>>>
>>> Today's Topics:
>>>
>>> 1. Re: handling of arrays (John Snyders) (Terence Parr)
>>> 2. Re: handling of arrays (John Snyders) (Terence Parr)
>>> 3. Re: Porting StringTemplate (Kay Roepke)
>>>
>>>
>>> --------------------------------------------------------------------
>>> --
>>>
>>> Message: 1
>>> Date: Tue, 30 Jan 2007 12:14:43 -0800
>>> From: Terence Parr <parrt at cs.usfca.edu>
>>> Subject: Re: [stringtemplate-interest] handling of arrays (John
>>> Snyders)
>>> To: Nate <misc at n4te.com>
>>> Cc: StringTemplate <stringtemplate-interest at antlr.org>
>>> Message-ID: <E02F2DC0-7AE7-4B2B-A69A-49E19AD2CCE8 at cs.usfca.edu>
>>> Content-Type: text/plain; charset=ISO-8859-1; delsp=yes;
>>> format=flowed
>>>
>>> crap. Ok, back to arrayiterator then.
>>> Ter
>>> On Jan 30, 2007, at 11:54 AM, Nate wrote:
>>>
>>>
>>>> Unless you are using Java 5+, you'd have to use System.arrayCopy to
>>>> copy the array to an Object array.
>>>>
>>>> -Nate
>>>>
>>>>
>>>> Terence Parr wrote:
>>>>
>>>>> Awesome! Heh, it's exactly what we want I think.
>>>>>
>>>>> Wait, class cast issue:
>>>>>
>>>>> public static Object convertArrayToList(Object value) {
>>>>> if ( value==null ) {
>>>>> return null;
>>>>> }
>>>>> if ( value.getClass().isArray() ) {
>>>>> return Arrays.asList((Object[])value); // CAST ISSUE!
>>>>> }
>>>>> return value;
>>>>> }
>>>>>
>>>>> won't work as value is not Object[] most of the time...but how do
>>>>> you get it to compile w/o the cast?
>>>>>
>>>>> Ter
>>>>>
>>>>> On Jan 30, 2007, at 9:13 AM, Harry Karadimas wrote:
>>>>>
>>>>>
>>>>>
>>>>>> Hi, I don't know if that relates to the previous post, but java
>>>>>> *does* have something
>>>>>> to encapsulate an array into a list, and that is the "asList"
>>>>>> method of the java.util.Arrays
>>>>>> class.
>>>>>>
>>>>>> Object[] myArray = ...
>>>>>> List myList = Arrays.asList(myArray);
>>>>>>
>>>>>> Harry Karadimas
>>>>>> _________________________________________________________________
>>>>>> ___
>>>>>> __ Dr Harry Karadimas Medecin Ingenieur resp. Recherche et
>>>>>> Developpement Departement d'Information Hospitalier CHU Henri
>>>>>> Mondor 51, av. du Mal de Lattre de Tassigny 94010 CRETEIL tel :
>>>>>> (00 33 1) 49 81 21 79 fax : (00 33 1) 49 81 27 08 secr.: (00 33
>>>>>> 1) 49 81 23 82 m.el.:harry.karadimas at hmn.ap-hop-paris.fr
>>>>>>
>>>>>>
>>>>>> stringtemplate-interest-request at antlr.org a ?crit :
>>>>>>
>>>>>>
>>>>>>> Send stringtemplate-interest mailing list submissions to
>>>>>>> stringtemplate-interest at antlr.org To subscribe or unsubscribe
>>>>>>> via the World Wide Web, visit http://www.antlr.org:8080/
>>>>>>> mailman/ listinfo/stringtemplate-interest or, via email, send a
>>>>>>> message with subject or body 'help' to stringtemplate-interest-
>>>>>>> request at antlr.org You can reach the person managing the list at
>>>>>>> stringtemplate-interest-owner at antlr.org When replying, please
>>>>>>> edit your Subject line so it is more specific than "Re:
>>>>>>> Contents of stringtemplate-interest digest..." Today's Topics:
>>>>>>> 1. Re: handling of arrays (John Snyders) 2. Re: inconsistency
>>>>>>> with length function (Oliver Flege)
>>>>>>> ----------------------------------------------------------------
>>>>>>> ---
>>>>>>> -- - Message: 1 Date: Sun, 28 Jan 2007 21:44:26 -0500 From:
>>>>>>> "John Snyders" <jjsnyders at rcn.com> Subject: Re:
>>>>>>> [stringtemplate- interest] handling of arrays To: "Terence
>>>>>>> Parr" <parrt at cs.usfca.edu>, "StringTemplate" <stringtemplate-
>>>>>>> interest at antlr.org> Message-ID:
>>>>>>> <PMEOJKDLMMHOHNEAMPBGGEJMCAAA.jjsnyders at rcn.com> Content-Type:
>>>>>>> text/plain; charset="US-ASCII"
>>>>>>>
>>>>>>>
>>>>>>>> -----Original Message----- From: stringtemplate-interest-
>>>>>>>> bounces at antlr.org [mailto:stringtemplate-interest-
>>>>>>>> bounces at antlr.org]On Behalf Of Terence Parr Sent: Saturday,
>>>>>>>> January 27, 2007 6:38 PM To: StringTemplate Subject: Re:
>>>>>>>> [stringtemplate-interest] handling of arrays On Jan 16, 2007,
>>>>>>>> at 9:40 PM, John Snyders wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>>> I noticed in ASTExpr.java the method convertArrayToList.
>>>>>>>>>
>>>>>>>>>
>>>>>>>> it is. just done to make things consistent...else have to
>>>>>>>> check for arrays everyone. gross, eh?
>>>>>>>>
>>>>>>>>
>>>>>>>>> It seems to me that this is wasteful. I have not looked at it
>>>>>>>>> too deep but why not handle arrays like other collections and
>>>>>>>>> wrap them in an ArrayIterator inside
>>>>>>>>> convertAnythingIteratableToIterator.
>>>>>>>>>
>>>>>>>>>
>>>>>>>> Interesting...ArrayIterator, eh? Does Sun have a standard one?
>>>>>>>> I don't see it. Do you mean I should create one real quick?
>>>>>>>>
>>>>>>>>
>>>>>>> There isn't one in the Java SDK (as far as I know) but jakarta
>>>>>>> commons has one http://jakarta.apache.org/commons/collections/
>>>>>>> api- release/org/apache/commons /collections/iterators/
>>>>>>> ArrayIterator.html ST probably shouldn't rely on this so you
>>>>>>> can create your own. It is straight forward. I created one
>>>>>>> before I found the one in commons collections. I can give it to
>>>>>>> you if you like (assuming I can find it). But again I didn't
>>>>>>> think this through fully.
>>>>>>>
>>>>>>>
>>>>>>>> Ter _______________________________________________
>>>>>>>> stringtemplate-interest mailing list stringtemplate-
>>>>>>>> interest at antlr.org http://www.antlr.org:8080/mailman/listinfo/
>>>>>>>> stringtemplate-interest
>>>>>>>>
>>>>>>>>
>>>>>>> ------------------------------ Message: 2 Date: Mon, 29 Jan
>>>>>>> 2007 10:25:24 +0100 From: Oliver Flege <o.flege at market-
>>>>>>> maker.de> Subject: Re: [stringtemplate-interest] inconsistency
>>>>>>> with length function To: StringTemplate <stringtemplate-
>>>>>>> interest at antlr.org> Message-ID: <45BDBD84.4040707 at market-
>>>>>>> maker.de> Content-Type: text/ plain; charset=ISO-8859-1 Hi,
>>>>>>> Terence Parr wrote:
>>>>>>>
>>>>>>>
>>>>>>>>> I think that the length method in ASTExpr.java should be
>>>>>>>>> changed as follows: From: } else if (attribute instanceof
>>>>>>>>> List) { i = ((List)attribute).size(); } To: } else if
>>>>>>>>> (attribute instanceof Collection) { i = ((List)
>>>>>>>>> attribute).size
>>>>>>>>> (); }
>>>>>>>>>
>>>>>>>>>
>>>>>>>> Howdy! OK, yep, good fix.
>>>>>>>>
>>>>>>>>
>>>>>>> even better would be } else if (attribute instanceof
>>>>>>> Collection) { i = ((Collection)attribute).size(); } :) Cheers,
>>>>>>> Oliver ------------------------------
>>>>>>> _______________________________________________ stringtemplate-
>>>>>>> interest mailing list stringtemplate-interest at antlr.org http://
>>>>>>> www.antlr.org:8080/mailman/listinfo/stringtemplate-interest End
>>>>>>> of stringtemplate-interest Digest, Vol 22, Issue 14
>>>>>>> *******************************************************
>>>>>>>
>>>>>>>
>>>>>> <harry.karadimas.vcf>
>>>>>> _______________________________________________
>>>>>> stringtemplate-interest mailing list
>>>>>> stringtemplate-interest at antlr.org
>>>>>> http://www.antlr.org:8080/mailman/listinfo/stringtemplate-
>>>>>> interest
>>>>>>
>>>>>>
>>>>> _______________________________________________
>>>>> stringtemplate-interest mailing list
>>>>> stringtemplate-interest at antlr.org
>>>>> http://www.antlr.org:8080/mailman/listinfo/stringtemplate-interest
>>>>>
>>>>>
>>>
>>>
>>>
>>> ------------------------------
>>>
>>> Message: 2
>>> Date: Tue, 30 Jan 2007 13:13:24 -0800
>>> From: Terence Parr <parrt at cs.usfca.edu>
>>> Subject: Re: [stringtemplate-interest] handling of arrays (John
>>> Snyders)
>>> To: StringTemplate <stringtemplate-interest at antlr.org>
>>> Message-ID: <5DE29967-5C4B-4700-8D51-EDB9CF147D51 at cs.usfca.edu>
>>> Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed
>>>
>>> Ok, i made an array wrapper and iterator. had to do both so a list
>>> is not purely an iterator, which has sideeffects.
>>>
>>> /** Do a standard conversion of array attributes to a List.
>>> Wrap the
>>> * array instead of copying like old version. Make an
>>> * ArrayWrappedInList that knows to create an ArrayIterator.
>>> */
>>> public static Object convertArrayToList(Object value) {
>>> if ( value==null ) {
>>> return null;
>>> }
>>> if ( value.getClass().isArray() ) {
>>> return new ArrayWrappedInList(value);
>>> }
>>> return value;
>>> }
>>>
>>> ArrayWrappedInList creates ArrayIterator. These are two new
>>> classes.
>>>
>>> Pushed to depot.
>>>
>>> Ter
>>>
>>> On Jan 30, 2007, at 9:13 AM, Harry Karadimas wrote:
>>>
>>>
>>>> Hi, I don't know if that relates to the previous post, but java
>>>> *does* have something
>>>> to encapsulate an array into a list, and that is the "asList"
>>>> method of the java.util.Arrays
>>>> class.
>>>>
>>>> Object[] myArray = ...
>>>> List myList = Arrays.asList(myArray);
>>>>
>>>> Harry Karadimas ____
>>>>
>>>
>>>
>>> ------------------------------
>>>
>>> Message: 3
>>> Date: Wed, 31 Jan 2007 02:21:11 +0100
>>> From: Kay Roepke <kroepke at classdump.org>
>>> Subject: Re: [stringtemplate-interest] Porting StringTemplate
>>> To: Shane Witbeck <shane at digitalsanctum.com>
>>> Cc: StringTemplate <stringtemplate-interest at antlr.org>
>>> Message-ID: <6789A417-4627-450E-A443-BF753E93862F at classdump.org>
>>> Content-Type: text/plain; charset=windows-1252; delsp=yes;
>>> format=flowed
>>>
>>>
>>> On Jan 28, 2007, at 1:04 AM, Shane Witbeck wrote:
>>>
>>>
>>>> It seems like porting to ECMAScript would be better strategically
>>>> since ActionScript is an extension of it and the amount of work out
>>>> there being done in JavaScript (AJAX, etc.).
>>>>
>>>> Shane
>>>>
>>>> On 1/27/07, Terence Parr <parrt at cs.usfca.edu> wrote:
>>>>
>>>>> This would be very involved and a huge project. ANTLR doesn't
>>>>> generate ActionScript so you'd need to parse everything by hand.
>>>>>
>>>>>
>>>
>>> Porting StringTemplate isn't exactly easy, esp. since it uses ANTLR
>>> v2. My attempts
>>> to do an Obj-C port haven't been exactly successful, mainly because
>>> ANTLR v3 threw
>>> up parsing ST :(
>>>
>>> I don't think that parsing ST by hand is a viable option, since
>>> it is
>>> a bit involved
>>> at times. I certainly wouldn't attempt it unless I was desperate...
>>> In the long run, though, v3 should be able to handle ST easily and
>>> that would make
>>> it a lot easier (even if you'd need to write a new v3 target).
>>>
>>> As to the ECMAScript target, I'm not sure whether the current
>>> engines
>>> are really fit to
>>> do recursive descent parsing in. All the engines I have seen have
>>> some real issues in
>>> regard to memory, ie. tend to be slow molasses (but I admit it would
>>> a cool thing to have
>>> now and then).
>>>
>>> my 0.02?,
>>>
>>> -k
>>>
>>>
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>> http://www.antlr.org:8080/mailman/listinfo/stringtemplate-interest
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>
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