Add MakeImm (short for MakeImmutable) and Imm (short for Immutable)

doc/ref/objects.xml

@@ -185,6 +185,7 @@ can assign values to components of a mutable record, or unbind them.
 
 <ManSection>
 <Func Name="MakeImmutable" Arg='obj'/>
+<Func Name="MakeImm" Arg='obj'/>
 
 <Description>
 One can turn the (mutable or immutable) object <A>obj</A> into an immutable
@@ -193,6 +194,7 @@ note that this also makes all subobjects of <A>obj</A> immutable,
 so one should call <Ref Func="MakeImmutable"/> only if <A>obj</A> and
 its mutable subobjects are newly created.
 If one is not sure about this, <Ref Func="Immutable"/> should be used.
+<Ref Func="MakeImm"/> provides a shorthand for <Ref Func="MakeImmutable"/>.
 <P/>
 Note that it is <E>not</E> possible to turn an immutable object into a
 mutable one;

hpcgap/lib/object.gd

@@ -252,6 +252,7 @@ InstallTrueMethod( IsCopyable, IsMutable);
 ## <#GAPDoc Label="Immutable">
 ## <ManSection>
 ## <Func Name="Immutable" Arg='obj'/>
+## <Func Name="Imm" Arg='obj'/>
 ##
 ## <Description>
 ## returns an immutable structural copy
@@ -263,12 +264,15 @@ InstallTrueMethod( IsCopyable, IsMutable);
 ## <P/>
 ## &GAP; will complain with an error if one tries to change an
 ## immutable object.
+## <P/>
+## <Ref Func="Imm"/> povides a shorthand for <Ref Func="Immutable"/>.
 ## </Description>
 ## </ManSection>
 ## <#/GAPDoc>
 ##
 BIND_GLOBAL( "Immutable", IMMUTABLE_COPY_OBJ );
-
+BIND_GLOBAL( "Imm", IMMUTABLE_COPY_OBJ );
+BIND_GLOBAL( "MakeImm", MakeImmutable );
 
 #############################################################################
 ##

lib/object.gd

@@ -226,6 +226,7 @@ InstallTrueMethod( IsCopyable, IsMutable);
 ## <#GAPDoc Label="Immutable">
 ## <ManSection>
 ## <Func Name="Immutable" Arg='obj'/>
+## <Func Name="Imm" Arg='obj'/>
 ##
 ## <Description>
 ## returns an immutable structural copy
@@ -237,12 +238,15 @@ InstallTrueMethod( IsCopyable, IsMutable);
 ## <P/>
 ## &GAP; will complain with an error if one tries to change an
 ## immutable object.
+## <P/>
+## <Ref Func="Imm"/> povides a shorthand for <Ref Func="Immutable"/>.
 ## </Description>
 ## </ManSection>
 ## <#/GAPDoc>
 ##
 BIND_GLOBAL( "Immutable", IMMUTABLE_COPY_OBJ );
-
+BIND_GLOBAL( "Imm", IMMUTABLE_COPY_OBJ );
+BIND_GLOBAL( "MakeImm", MakeImmutable );
 
 #############################################################################
 ##

tst/testinstall/immutable.tst

@@ -0,0 +1,60 @@
+#############################################################################
+##
+#W immutable.tst GAP Library
+##
+##
+#Y Copyright (C) 2017, University of St Andrews, Scotland
+##
+##
+gap> START_TEST("immutable.tst");
+gap> IS_IDENTICAL_OBJ(Immutable, Imm);
+true
+gap> IS_IDENTICAL_OBJ(MakeImmutable, MakeImm);
+true
+gap> IS_IDENTICAL_OBJ(Immutable, MakeImmutable);
+false
+gap> IsMutable(1);
+false
+gap> IS_IDENTICAL_OBJ(1,Immutable(1));
+true
+gap> IS_IDENTICAL_OBJ(1,Imm(1));
+true
+gap> IS_IDENTICAL_OBJ(1,MakeImmutable(1));
+true
+gap> IS_IDENTICAL_OBJ(1,MakeImm(1));
+true
+gap> x := [1,2,3];
+[ 1, 2, 3 ]
+gap> IsMutable(x);
+true
+gap> IsMutable(Immutable(x));
+false
+gap> x = Immutable(x);
+true
+gap> IsMutable(Imm(x));
+false
+gap> x = Imm(x);
+true
+gap> IS_IDENTICAL_OBJ(x, Imm(x));
+false
+gap> IsMutable(x);
+true
+gap> x;
+[ 1, 2, 3 ]
+gap> IS_IDENTICAL_OBJ(x, MakeImmutable(x));
+true
+gap> IsMutable(x);
+false
+gap> x;
+[ 1, 2, 3 ]
+gap> IsMutable(Group(()));
+false
+gap> IsMutable(StabChainImmutable(Group(())));
+false
+gap> IsMutable(StabChainMutable(Group(())));
+true
+gap> STOP_TEST( "immutable.tst", 1);
+
+#############################################################################
+##
+#E