diff --git a/src/AutGroup.jl b/src/AutGroup.jl
index 10b3bc5..87ed518 100644
--- a/src/AutGroup.jl
+++ b/src/AutGroup.jl
@@ -4,16 +4,16 @@
 #
 ###############################################################################
 
-immutable AutSymbol <: GSymbol
+@compat struct AutSymbol <: GSymbol
    str::String
    pow::Int
    ex::Expr
    func::Function
 end
 
-typealias AutGroupElem GWord{AutSymbol}
+@compat AutGroupElem = GWord{AutSymbol}
 
-type AutGroup <: AbstractFPGroup
+@compat mutable struct AutGroup <: AbstractFPGroup
    objectGroup::Group
    gens::Vector{AutSymbol}
 end
diff --git a/src/FPGroups.jl b/src/FPGroups.jl
index 4ab27c8..6705329 100644
--- a/src/FPGroups.jl
+++ b/src/FPGroups.jl
@@ -4,14 +4,14 @@
 #
 ###############################################################################
 
-immutable FPSymbol <: GSymbol
+@compat struct FPSymbol <: GSymbol
    str::String
    pow::Int
 end
 
-typealias FPGroupElem = GWord{FPSymbol}
+@compat FPGroupElem = GWord{FPSymbol}
 
-type FPGroup <: AbstractFPGroup
+@compat mutable struct FPGroup <: AbstractFPGroup
    gens::Vector{FPSymbol}
    rels::Dict{FPGroupElem, FPGroupElem}
 
diff --git a/src/FreeGroup.jl b/src/FreeGroup.jl
index a023395..7fd9fff 100644
--- a/src/FreeGroup.jl
+++ b/src/FreeGroup.jl
@@ -4,14 +4,14 @@
 #
 ###############################################################################
 
-immutable FreeSymbol <: GSymbol
+@compat struct FreeSymbol <: GSymbol
    str::String
    pow::Int
 end
 
-typealias FreeGroupElem GWord{FreeSymbol}
+@compat FreeGroupElem = GWord{FreeSymbol}
 
-type FreeGroup <: AbstractFPGroup
+@compat mutable struct FreeGroup <: AbstractFPGroup
    gens::Vector{FreeSymbol}
    #     order::Vector{T}
    #     fastmult_table::Array{Int,2}
diff --git a/src/Groups.jl b/src/Groups.jl
index dfb027e..a4ae24d 100644
--- a/src/Groups.jl
+++ b/src/Groups.jl
@@ -1,4 +1,5 @@
 module Groups
+using Compat
 
 using Nemo
 import Nemo: Group, GroupElem, Ring
@@ -24,7 +25,7 @@ doc"""
 > * `pow` which is the (multiplicative) exponent of a symbol.
 
 """
-abstract GSymbol
+abstract type GSymbol end
 
 doc"""
     W::GWord{T<:GSymbol} <:GroupElem
@@ -42,7 +43,7 @@ doc"""
 
 """
 
-type GWord{T<:GSymbol} <: GroupElem
+@compat mutable struct GWord{T<:GSymbol} <: GroupElem
     symbols::Vector{T}
     savedhash::UInt
     modified::Bool
@@ -78,11 +79,11 @@ convert{T<:GSymbol}(::Type{GWord{T}}, s::T) = GWord{T}(T[s])
 #
 ###############################################################################
 
-xor(a,b) = a $ b
 
 function hash(W::GWord, h::UInt)
     W.modified && reduce!(W)
-    return xor(W.savedhash, h)
+    @compat res = xor(W.savedhash, h)
+    return res
 end
 
 function deepcopy_internal{T<:GSymbol}(W::GWord{T}, dict::ObjectIdDict)