S703975@UWEC.BITNET (ANDREW TREMBLEY) (12/05/89)
Thanks for answering. My problem is that whenever I try a NEW or a DISPOSE the compiler barfs. I assume that this is because it has to be imported from a module, but I have no idea which one. I'd much like to be able to use MetCom (it's editor is better than VMS Edit (EDT) and it's more convenient than using Work and kermiting), but without NEW and DISPOSE, my ADTs won't work. Thanks much Andy
GEROFSKY@UCF1VM.BITNET (Lara Gerofsky) (12/05/89)
The NEW and DISPOSE are supported by ALLOCATE and DEALLOCATE respectively from the Storage library. Your welcome, Lara Gerofsky GEROFSKY at UCF1VM
Bob_Campbell.ZORRO@GATEWAY.QM.APPLE.COM (Bob Campbell) (12/05/89)
I don't think that MetCom supports NEW or DISPOSE, N. Wirth choice to delete these features from the language, as they required ALLOCATE, and DEALLOCATE to be imported from another module. NEW is ALLOCATE(x,SIZE(x)) DISPOSE is DEALLOCATE(x,SIZE(x)) Also note that TSIZE was also removed from the language, and SIZE was redefined to handle both variables and types (most compilers still support TSIZE). It should not be too hard to write a script to convert them. s/ALLOCATE(\([~,]*\),SIZE(.*))/NEW(\1)/gp s/DEALLOCATE(\([~,]*\),SIZE(.*))/DISPOSE(\1)/gp My vi is a little bit rusty, in MPW it would be: replace /ALLOCATE\(([option-l,]*)option-r1,SIZE(option-x))/ "NEW(option-r1)" replace /DEALLOCATE\(([option-l,]*)option-r1,SIZE(option-x))/ "DISPOSE(option-r1)" (It is a little hard to some the MPW commands using Usenet which does not have the full Macintosh Character Set). I don't have a cute trailer************** Applelink: BOBC (BOBC@Applelink.apple.com) Quickmail: Bob Campbell@ZORRO (Bob_Campbell.ZORRO@gateway.qm.apple.com)
kherron@MS.UKY.EDU (12/05/89)
(ooh, finally an M-2 question I can answer!) NEW and DISPOSE, if your compiler has them, will be part of the SYSTEM module. I say "if your compiler has them" because Wirth's latest M-2 spec does not include NEW and DISPOSE--instead, use the ALLOCATE and DEALLOCATE procedures from STORAGE, along with the SYSTEM procedure TSIZE, which gives the size of a declared type. The pseudo-declaration for TSIZE looks like this: PROCEDURE TSIZE(<any type>): INTEGER; Like I said, it's in SYSTEM also. Kenneth Herron
marti@ethz.UUCP (Robert Marti) (12/06/89)
In article <891204.13351181.096571@UWEC.CP6>, S703975@UWEC.BITNET (ANDREW TREMBLEY) writes: > My problem is that whenever I try a NEW or a DISPOSE the compiler barfs. > I assume that this is because it has to be imported from a module, but > I have no idea which one. Let me start with a disclaimer: I have never used MetCom Modula-2. I do know a couple of other Modula-2 implementations though, in particular the MacMETH system on which MetCom M-2 is based, I believe. The book "Programming in Modula-2, 3rd Ed." by N.Wirth, p.76, states (emphasis added by me): [Pointer variables] are created by a call of an allocation procedure, usually available from a library module. TYPICALLY, a module Storage may provide a procedure Allocate. The state- ment Allocate(p0, SIZE(Node)) then creates a variable of type Node and assigns a pointer pointing to that variable to [...] p0. and, a little later: In SOME implementations, the statement Allocate(p0, SIZE(Node)) can be abbreviated as NEW(p0) . Assuming that this is all true for MetCom M-2 -- which may well not be the case -- you'd have to import Allocate from Storage anyway, EVEN WHEN using the abbreviation NEW. However, it is not entirely clear which of the two solutions below work: FROM Storage IMPORT Allocate; VAR p: POINTER TO ... ; ... NEW(p); or IMPORT Storage; VAR p: POINTER TO ... ; ... NEW(p); Note that in the MacMETH system, there is a module Storage which exports ALLOCATE (!) and DEALLOCATE and a module System (!) which exports Allocate and Deallocate. NEW is not supported. So, check the documentation to figure out from which module either Allocate or ALLOCATE is exported. Then check if NEW is supported. I hope this helps. -- Robert Marti Phone: +41 1 256 52 36 Institut fur Informationssysteme ETH-Zentrum CSNET/ARPA: marti%inf.ethz.ch@relay.cs.net CH-8092 Zurich, Switzerland UUCP: ...uunet!mcvax!ethz!marti
UK4H@DKAUNI2.BITNET (JAE) (12/12/89)
Hi all! I just wanted, no, I MUST add my 2 cents worth to this one. Bob Campbell wrote: > NEW is ALLOCATE(x,SIZE(x)) > DISPOSE is DEALLOCATE(x,SIZE(x)) THIS IS WRONG!!!! Instead you have to write ALLOCATE(x,SIZE(x^)); DEALLOCATE(x,SIZE(x^)); '^' is the caret (dereferencing 'operator'). I once forgot this little thing, and the error was REALLY hard to find (I had to do without a debugger, though). I'm quite sure that Bob just forgot this, because it wont run properly if you do forget it. Well, one final note on his vi and MPW scripts(?): I don't think they are correct, either, 'cause I didn't notice a caret there! Unfortunately, I have neither access to vi nor to MPW, sigh. So can some kind soul out there (or you, Bob) please correct it (if anyone needs it). bye, JAE Juergen A. Erhard eMail: uk4h@dkauni2.bitnet phone: (GERMANY) 0721/591602 "You know that it's monday when you wake up and it's tuesday." Garfield
cmp8118@sys.uea.ac.uk (D.S. Cartwright) (12/13/89)
UK4H@DKAUNI2.BITNET (JAE) writes: >Bob Campbell wrote: >> NEW is ALLOCATE(x,SIZE(x)) >> DISPOSE is DEALLOCATE(x,SIZE(x)) >THIS IS WRONG!!!! >Instead you have to write > ALLOCATE(x,SIZE(x^)); > DEALLOCATE(x,SIZE(x^)); >'^' is the caret (dereferencing 'operator'). The way I do it is thus: If you have a type declaration TYPE Dave = POINTER TO Fred ; Fred = RECORD Field1 : ARRAY[0..30] OF INTEGER ; Field2 : ARRAY[0..9] OF CHAR ; Pointer : Dave ; CEND ; then VAR Variable : Dave ; you can then do ALLOCATE (Variable,TSIZE(Fred)) where ALLOCATE is IMPORTed from STORAGE and TSIZE from SYSTEM (or the other way round, I think this is the right way though). One thing you have to make sure of is that you put TSIZE(Fred) and not, by a slip of the keyboard, TSIZE(Dave), else you'll be trying to place something of RECORD type in a space the size of a POINTER. Doesn't work, and it's a sod to find out why (I know !!!!). Just a thought ..... Dave Cartwright, School of Information Systems, University of East Anglia, Norwich, England. Note : I am only a student => I am pretty thick really => Don't shout at me too much if I'm wrong.
Bob_Campbell.ZORRO@GATEWAY.QM.APPLE.COM (Bob Campbell) (12/14/89)
How embarrassingI, I should know better then to pass out code with out testing it. For the record I don't use MetCom's standalone product, but instead use a MPW based Modula-2 product which was sold by TML systems and will soon be licensed thru MetroWorks (the MetCom people). I understand that the MPW product (from Apple) is a little bit pricey, but I refuse to use a development environment which can't be scripted, and does not support regular expressions. I don't have a cute trailer************** Applelink: BOBC (BOBC@Applelink.apple.com) Quickmail: Bob Campbell@ZORRO (Bob_Campbell.ZORRO@gateway.qm.apple.com)
rsutc@fornax.UUCP (Rick Sutcliffe) (12/14/89)
In article <"89-12-11-21:03:38.02*UK4H"@DKAUNI2.BITNET>, UK4H@DKAUNI2.BITNET (JAE) writes: > Bob Campbell wrote: > > NEW is ALLOCATE(x,SIZE(x)) > > DISPOSE is DEALLOCATE(x,SIZE(x)) > THIS IS WRONG!!!! > Instead you have to write > ALLOCATE(x,SIZE(x^)); > DEALLOCATE(x,SIZE(x^)); Actually, its still not right. It is inadvisable to say the least to do SIZE(x^) before the ALLOCATE has been done. What if x is NIL? Do it this way: TYPE MyThingy = whatever; MyPoint = POINTER TO MyThingy; VAR x: MyPoint; ALLOCATE (x, SIZE (MyThingy)) Rick Sutcliffe
Bob_Campbell.ZORRO@gateway.qm.apple.Com (Bob Campbell) (12/15/89)
For the record the following peice of code works. I know I tested it this time. TYPE MyThingy = RECORD x,y,z : INTEGER END; MyPoint = POINTER TO MyThingy; VAR x: MyPoint; BEGIN ALLOCATE (x, SIZE (x^)); It is true that x^ might dereference the variable x, but because this is only one level deep, the dereferencing code is not generated (by any of the MetCom products). A more complex expression like x^.y^.z^ might cause more problems (the MPW compiler does not like this at all, I will have to see if that can be fixed). It could be argued that this method should only be used when you need to convert between NEW and ALLOCATE, but I can't think of can good reasons that require that to be done more then once. The bottom line is that if you don't write your code intending to use NEW, then you can write code that works using the actual type instead of dereferencing the variable to get it's size. This code is portable and would work with almost any Modula-2 compiler. As a side note I don't use ALLOCATE normally I call the Macintosh routine NewPtr. In the last message I said something about "Apple's MPW Product" I was talking about the MPW shell. Apple does not have a Modula-2 product, and the only Macintosh Modula-2 compilers that I am aware of are SemperSoft, P1 and MetCom (aka MetroWorks). Applelink: BOBC (BOBC@Applelink.apple.com) Quickmail: Bob Campbell@ZORRO (Bob_Campbell.ZORRO@gateway.qm.apple.com)