Add show method for character tables (#37)

src/CharTable.jl

@@ -102,8 +102,12 @@ Omitting `x` will return the names of all importable character tables.
 
 # Examples
 ```jldoctest
-julia> g=genchartab(\"GL2\");
-
+julia> g = genchartab("GL2")
+Generic character table
+  of order q^4 - q^3 - q^2 + q
+  with 4 irreducible character types
+  with 4 class types
+  with parameters (i, j, l, k)
 ```
 """
 genchartab(x::String) = gentab(x, "Tables")
@@ -118,8 +122,12 @@ Omitting `x` will return the names of all importable greenfunctions.
 
 # Examples
 ```jldoctest
-julia> g=greenfuntab(\"GL2\");
-
+julia> g = greenfuntab("GL2")
+Generic character table
+  of order q^4 - q^3 - q^2 + q
+  with 2 irreducible character types
+  with 2 class types
+  without parameters
 ```
 """
 greenfuntab(x::String) = gentab(x, "Greenfunctions")

src/Show.jl

@@ -1,6 +1,25 @@
 export chartypes, irrchartypes, classtypes, status, printinfotab, printval, printinfoclass, printinfochar, printclassparam, printcharparam, centord, chardeg, nrchars, nrclasses, nrparams, params
 # TODO PrintValPhi, PrintToTex?
 
+import Oscar: pretty, Indent
+
+function Base.show(io::IO, t::Table)
+    io = pretty(io)
+    println(io, "Generic character table", Indent())
+    println(io, "of order ", t.order)
+    c = congruence(t)
+    if c !== nothing
+        println(io, "restricted to q congruent to ", c[1], " modulo ", c[2])
+    end
+    println(io, "with ", irrchartypes(t)," irreducible character types")
+    println(io, "with ", classtypes(t)," class types")
+    if t isa SimpleCharTable
+        print(io, "without parameters")
+    else
+        print(io, "with parameters ", params(t)[2])
+    end
+end
+
 """
     chartypes(t::Table)
 
@@ -48,6 +67,10 @@ function classtypes(t::Table)
 	size(t.table, 2)
 end
 
+# TODO: document (and export) this?
+congruence(x::CharTable) = x.congruence
+congruence(x::SimpleCharTable) = nothing
+
 """
     status(t::Table)