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1.9.1 Changes in the CoCoA language
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CoCoA-5 is largely, but not completely, backward-compatible with CoCoA-4.
Some commands/functions have changed name; others have been removed or
replaced. Here we give a little guidance to help update your CoCoA-4
programs to CoCoA-5/
The operator
Not
has been replaced by the function
not(...)
.
/*C4*/ If Not X IsIn L Then ... EndIf;
/*C5*/ If not(X IsIn L) Then ... EndIf;
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Several functions modify one of their arguments (e.g.
append
,
sort
); CoCoA-5 wants these arguments to be identified with the new
keyword
ref
, and will issue a warning if you don't do this
(just to make sure you know that
L
will be modified).
/*C4*/ L := [1,2,3]; Append(L, 4);
/*C5*/ L := [1,2,3]; append(ref L, 4);
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Implicit multiplication has gone: either write
x*y
instead of
xy
for every product, or use
CoCoA-4 mode
.
/*C4*/ F := 3xyzt;
/*C5*/ F := 3*x*y*z*t; OR F := ***3xyzt***;
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Many CoCoA-4 functions would employ the
CurrentRing
implicitly (e.g.
NumIndets()
,
CoeffRing()
). They now require an explicit argument;
you can pass
CurrentRing
as the argument, but inside a function you must
make that system variable visible via the command
TopLevel
.
/*C4*/ Define LastIndet() Return Last(Indets()); EndDefine;
/*C5*/ Define LastIndet()
TopLevel CurrentRing;
Return last(indets(CurrentRing));
EndDefine;
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However, we encourage you to consider modifying your function so that
it does not depend on
CurrentRing
; e.g. you can find
out to which ring a value belongs by calling the function
RingOf
.
/*C5*/ I := ideal(x,y^2); NumIndets(RingOf(I));
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The function
LinKer
has been replaced by
LinKerBasis
,
and there is a new function called
LinKer
which produces a matrix.
More generally, see also the CoCoA-4 "translation table" in the
CoCoAManual directory or at
http://cocoa.dima.unige.it/cocoalib/doc/CoCoATranslationTable.html