add FPGroups.jl

src/FPGroups.jl

@@ -0,0 +1,52 @@
+module FinitelyPresentedGroups
+
+using Groups
+
+abstract Group
+
+immutable FPSymbol{T<:Group} <: GSymbol
+    gen::String
+    pow::Integer
+    parent::T
+end
+
+# FPSymbol(x::String, G::Group) = FPSymbol(x,1,G)
+# FPSymbol(s::GSymbol, G::Group) = FPSymbol(s.gen, s.pow, G)
+
+typealias FPGroupElem GWord{FPSymbol}
+
+immutable FPGroup <: Group
+    gens::Vector{FPSymbol}
+    rels::Vector{FPGroupElem}
+#     order::Vector{T}
+#     fast_multable::Array{Int,2}
+    function FPGroup{T<:GSymbol}(gens::Vector{T}, rels::GWord{T})
+        G = new()
+        gens = [FPSymbol{G}(g.gen, G) for g in gens]
+        rels = []
+    end
+end
+
+FPGroup() = FPGroup(Vector{FPSymbol}(), Vector{GWord{FPSymbol}}())
+
+function show(io::IO, G::FPGroup)
+    print(io, "Finitely presented group on $(length(G.gens)) gens and $(length(G.rels)) relations:\n")
+    print(io, "gens:\t", join([g.gen for g in G.gens], ","),"\n")
+    print(io, "rels:\t", join([rel for rel in G.rels], ","),"\n")
+end
+
+function add_gen!{T<:GSymbol}(G::FPGroup, g::T)
+    if !(g in G.gens)
+        push!(G.gens, g)
+    end
+    return G
+end
+
+function add_rel!{T<:FPSymbol}(G::FPGroup, w::GWord{T})
+    if !(w in G.rels)
+        push!(G.rels, w)
+    end
+    return G
+end
+
+end #of module FinitelyPresentedGroups