#
#	Implementation of table
#
#	Gaston H. Gonnet (April 24th, 2002)
#	rewritten for new tables using hashing, June 24th, 2010
#
table := proc( Table_Values, Table_Default ) option polymorphic, NoIndexing;
if nargs=0 then noeval(procname([],unassigned))
elif not type(Table_Values,list(set)) then procname([],args)
elif nargs=1 then noeval(procname(Table_Values,unassigned))
elif nargs>2 then error('too many arguments')
else if length(Table_Values) > 0 then
	  # has to reinsert everything, as it may have been on a different system
	  t2 := noeval(table( [], Table_Default ));
	  for w in Table_Values do for v in w do t2[v[1]] := op(v[2]) od od;
	  t2
     else noeval(procname(args)) fi
fi
end:


# table_select is handled by the kernel completely


table_print := proc( tab ) option internal;
if op(1,tab)=[] then print( '[]\n' );  return() fi;
for z in Indices(tab) do
    r := tab[z];
    printf( '%a  -->  %a\n', z, If( length([r])=1, r, symbol('')(r) ))
od;
end:


# add the contents of two tables
table_plus := proc( t1:table, t2:table ) option internal;
r := copy(t1);
for i in Indices(t2) do r[i] := r[i]+t2[i] od:
r
end:


table_type := structure(anything,table):


# Indices_iterator is removed in favour of the Iterator function
# which has no computational advantage.  The Iterator() function has
# the advantage that can be used by itself.  GhG (19.12.2010)

Indices := proc( tab:table ) option internal;
{ seq( seq(z[1],z=w), w=op(1,tab)) }
end:

# convert a table into a list of pairs
table_list := proc(tab:table ) 
  l := []:
  for i in Indices(tab) do l := append(l, [i, tab[i]]) od:
  return( l );
end: