Skip to content

Commit

Permalink
Use BindGlobal more to prevent accidents
Browse files Browse the repository at this point in the history 
... i.e., prevent users or other packages from accidentally replacing our functions
  • Loading branch information
@fingolfin
fingolfin committed Feb 3, 2023
1 parent d641340 commit d7f3ae3
Showing 1 changed file with 28 additions and 29 deletions.
57 changes: 28 additions & 29 deletions gap/coho4.g
View file
Original file line number Diff line number Diff line change
Expand Up @@ -13,7 +13,7 @@ DeclareInfoClass("InfoCohomolo");
##
#V COHOMOLO . . . . . . . . . . . . . . . . . . . . . . . . global variable
##
COHOMOLO := rec(
BindGlobal("COHOMOLO", rec(
Multiplier := [],
CoDim1 := 0,
CoDim2 := 0,
Expand All @@ -22,7 +22,7 @@ COHOMOLO := rec(
RM_F := "rm -f ",
CALL := DirectoriesPackagePrograms("cohomolo")
#This is the directory of the external executables
);
) );

#############################################################################
##
Expand Down Expand Up @@ -174,7 +174,7 @@ end;
## Apart from checking validity, a Sylow <p>-subgroup of <G> is calculated.
## The record (with various components set) is returned.
##
CHR := function ( arg )
BindGlobal( "CHR", function ( arg )
local chr, na, G, p, F, mats, Ggens, Fgens, ng, deg, dim, error, mat, rels,
w, i, d;
na := Number(arg);
Expand Down Expand Up @@ -273,15 +273,15 @@ CHR := function ( arg )
chr.verbose := false;

return chr;
end;
end );

#############################################################################
##
#F IsCHR( x ) . . . . . . . . checks if the argument is a cohomology record.
##
IsCHR := function(x)
BindGlobal( "IsCHR", function(x)
return IsRecord(x) and IsBound(x.isCHR) and x.isCHR=true;
end;
end );

#############################################################################
##
Expand All @@ -297,7 +297,7 @@ end;
## It selects S2 as soon as it has found an S2 with index <= <n>.
## The sequence is stored as chr.chain.
##
FindSubSeq := function ( chr, n )
BindGlobal( "FindSubSeq", function ( chr, n )
local G, P, p, deg, seq, H, N, foundsub, orb, norbs, orbdone,
sylind, bestind, ind, badind,
orbsize, bestsub, orbno, orbstab, Z, OZ, OZG, centels, cent,
Expand Down Expand Up @@ -490,7 +490,7 @@ FindSubSeq := function ( chr, n )
fi;

chr.chain := seq;
end;
end );

#############################################################################
##
Expand All @@ -510,7 +510,7 @@ end;
## <filename> is the name of the base of the files to be created for use of
## the external package. The files have names of form <filename>.<suffix>.
##
Cohomolo := function( chr, mult, pres, first, filename )
BindGlobal( "Cohomolo", function( chr, mult, pres, first, filename )
local deg, G, P, p, base, lc, nint, ch, F, mats, i, optstring, callstring,
ct, ok;

Expand Down Expand Up @@ -700,7 +700,7 @@ Cohomolo := function( chr, mult, pres, first, filename )

Info(InfoCohomolo,1," Removing temporary files." );
Exec( Concatenation( COHOMOLO.RM_F, filename, ".*" ) );
end;
end );

#############################################################################
##
Expand All @@ -723,7 +723,7 @@ end;
## This function is not intended to be called directly - it is accessed by
## the individual functions, and by ExtPresentation.
##
CalcExtPres := function( arg )
BindGlobal( "CalcExtPres", function( arg )
local chr, mult, vec, E, EG, p, F, ng, codim, mp, dim, rels, rel, relval, w,
mats, row, modrv, multrv, f, table, rt, i, j, k, Erels;

Expand Down Expand Up @@ -833,7 +833,7 @@ CalcExtPres := function( arg )
Add(Erels,w);
od;
return E/Erels;
end;
end );

#############################################################################
##
Expand All @@ -843,15 +843,15 @@ end;
## <chr> is a cohomology record.
## The result is returned as a list of the abelian invariants.
##
SchurMultiplier := function( chr )
BindGlobal( "SchurMultiplier", function( chr )
if not IsCHR(chr) then
Error("First argument of Cohomolo must be a cohomology record");
fi;
if not IsBound(chr.multiplier) then
Cohomolo(chr,true,false,false, TmpName() );
fi;
return chr.multiplier;
end;
end );

#############################################################################
##
Expand All @@ -861,15 +861,15 @@ end;
## if <chr>.fpgp and <chr>.permgp are isomorphic.
## The p-cover is returned as an fp-group.
##
CoveringGroup := function( chr )
BindGlobal( "CoveringGroup", function( chr )
if not IsCHR(chr) then
Error("First argument of Cohomolo must be a cohomology record");
fi;
if not IsBound(chr.multrelvals) then
Cohomolo(chr,true,true,false, TmpName() );
fi;
return CalcExtPres(chr,true);
end;
end );

#############################################################################
##
Expand All @@ -878,15 +878,15 @@ end;
##
## <chr> is a cohomology record with <chr>.matrices defined.
##
FirstCohomologyDimension := function( chr )
BindGlobal( "FirstCohomologyDimension", function( chr )
if not IsCHR(chr) then
Error("First argument of Cohomolo must be a cohomology record");
fi;
if not IsBound(chr.codim1) then
Cohomolo(chr,false,false,true, TmpName() );
fi;
return chr.codim1;
end;
end );

#############################################################################
##
Expand All @@ -895,15 +895,15 @@ end;
##
## <chr> is a cohomology record with <chr>.matrices defined.
##
SecondCohomologyDimension := function( chr )
BindGlobal( "SecondCohomologyDimension", function( chr )
if not IsCHR(chr) then
Error("First argument of Cohomolo must be a cohomology record");
fi;
if not IsBound(chr.codim2) then
Cohomolo(chr,false,false,false, TmpName() );
fi;
return chr.codim2;
end;
end );

#############################################################################
##
Expand All @@ -913,12 +913,12 @@ end;
## To use this <chr>.fpgp and <chr>.matrices must both be define
## This is a routine calculation and does not call Cohomolo.
##
SplitExtensionCHR := function( chr )
BindGlobal( "SplitExtensionCHR", function( chr )
if not IsCHR(chr) then
Error("First argument of Cohomolo must be a cohomology record");
fi;
return CalcExtPres(chr,false,[]);
end;
end );

#############################################################################
##
Expand All @@ -935,7 +935,7 @@ end;
## By default, <vec> is taken to be [1,0,...,0], where the length is equal
## to Dim(H^2(G,M)).
##
NonsplitExtension := function( arg )
BindGlobal( "NonsplitExtension", function( arg )
local chr, vec, i;
if Number(arg)<>1 and Number(arg)<>2 then
Error("Number of arguments of NonSplitExtension wrong");
Expand All @@ -957,7 +957,7 @@ NonsplitExtension := function( arg )
for i in [2..chr.codim2] do vec[i]:=0; od;
fi;
return CalcExtPres(chr,false,vec);
end;
end );

#############################################################################
##
Expand All @@ -971,7 +971,7 @@ end;
## be faithful.
## It is a straightforward application of standard GAP functions.
##
PermRep := function(F,K)
BindGlobal( "PermRep", function(F,K)
local ng, Ggens, GGi, CT, i;
if not IsFpGroup(F) or not IsSubgroup(F,K) then
Error("PermRep(F,K): K must be a subgroup of the fp-group F");
Expand All @@ -982,7 +982,7 @@ PermRep := function(F,K)
Ggens := [];
for i in [1..ng] do Ggens[i] := GGi[2*i-1]; od;
return Group(Ggens,());
end;
end );

#############################################################################
##
Expand All @@ -996,7 +996,7 @@ end;
## It is only really useful for moderately small groups - currently, its
## use is restricted to groups of order at most 32767.
##
CalcPres := function( chr )
BindGlobal( "CalcPres", function( chr )
local deg, G, base, F, Fg, Fr, optstring, callstring, ng, ordgen, o, rel,
i, l, w, g, h, ct, neg, filename;

Expand Down Expand Up @@ -1088,5 +1088,4 @@ CalcPres := function( chr )

Unbind(chr.permrels);
chr.fpgp := F/Fr;
end;

end );

0 comments on commit d7f3ae3

Please sign in to comment.