From j.l.schonfelder@liverpool.ac.uk Fri Jul 4 17:58:24 1997 Received: from pcmail.liv.ac.uk (pp@pcmail.liv.ac.uk [138.253.252.13]) by dkuug.dk (8.6.12/8.6.12) with SMTP id RAA17463 for ; Fri, 4 Jul 1997 17:58:23 +0200 Received: from jlspcnt.liv.ac.uk [138.253.102.118] by pcmail.liv.ac.uk with smtp (Exim 1.61 #3) id 0wkAkW-00076i-00; Fri, 4 Jul 1997 16:58:20 +0100 From: Lawrie Schonfelder Sender: J.L.Schonfelder@liverpool.ac.uk Reply-To: j.l.schonfelder@liverpool.ac.uk To: SC22/WG5 members Subject: ELEMENTAL assignment in F95 Varying Strings Message-ID: Date: Fri, 4 Jul 1997 16:58:18 +0100 (British Summer Time) Priority: NORMAL X-Mailer: Simeon for Win32 Version 4.1.1 Build (17) X-Authentication: IMSP MIME-Version: 1.0 Content-Type: TEXT/PLAIN; CHARSET=US-ASCII In order to deal with the IMO unnecessary restriction on elementary procedures imposed on F95 I have to do something like this for string to string assignment. !----- ASSIGNMENT Procedures -------------------------------------------------! ELEMENTAL SUBROUTINE s_ass_s(var,expr) type(VARYING_STRING),INTENT(OUT) :: var type(VARYING_STRING),INTENT(IN) :: expr ! assign a string value to a string variable overriding default assignement ! reallocates string variable to size of string value and copies characters CHARACTER,ALLOCATABLE :: tmpexpr(:) ALLOCATE(tmpexpr(1:SIZE(expr%chars))) tmpexpr = expr%chars IF(ASSOCIATED(var%chars))DEALLOCATE(var%chars) ALLOCATE(var%chars(1:SIZE(tmpexpr))) var%chars = tmpexpr ENDSUBROUTINE s_ass_s The temp is necessary to deal with this sort of situation stra = stra Without it the deallocation destroys the value of the expression before allocating the space to contain the new copy. This is a very heavy handed solution to a rather small problem. I have to think some more about the whole structure of the module. I think it may be the case that it is only when there is total overlap of var and expr that the problem arrises. I think in all other cases where there would be what looks like a partial overlap, e.g. stra=stra//strb the actual expr value is held in some temporary space already and there is no real overlap. If I can convince myself that this is the case then the code could become ELEMENTAL SUBROUTINE s_ass_s(var,expr) type(VARYING_STRING),INTENT(OUT) :: var type(VARYING_STRING),INTENT(IN) :: expr ! assign a string value to a string variable overriding default assignement ! reallocates string variable to size of string value and copies characters IF(ASSOCIATED(var%chars,expr%chars))THEN RETURN ! identity assignment do nothing ELSEIF(ASSOCIATED(var%chars))THEN DEALLOCATE(var%chars) ALLOCATE(var%chars(1:SIZE(expr%chars))) var%chars = expr%chars ENDIF ENDSUBROUTINE s_ass_s -- Lawrie Schonfelder Director, Computing Services Dept. The University of Liverpool, UK, L69 7ZF Phone: 44(151)794 3716, Fax: 44(151)794 3759