From 30d58445dfa7abf378f6cf37c065b66b541284de Mon Sep 17 00:00:00 2001
From: Marek Kaluba <kalmar@amu.edu.pl>
Date: Thu, 13 Oct 2022 23:21:42 +0200
Subject: [PATCH] letters(A::Alphabet) are no more

---
 src/aut_groups/mcg.jl    |  2 +-
 src/aut_groups/sautFn.jl |  4 ++--
 src/autgroups.jl         |  2 +-
 src/types.jl             | 12 +++++-------
 test/AutSigma3.jl        |  8 +++-----
 5 files changed, 12 insertions(+), 16 deletions(-)

diff --git a/src/aut_groups/mcg.jl b/src/aut_groups/mcg.jl
index 5d9041f..8b3bbce 100644
--- a/src/aut_groups/mcg.jl
+++ b/src/aut_groups/mcg.jl
@@ -64,7 +64,7 @@ function SurfaceGroup(genus::Integer, boundaries::Integer)
     F = FreeGroup(alphabet(rws))
     rels = [F(lhs)=>F(rhs) for (lhs,rhs) in word_rels]
 
-    return SurfaceGroup(genus, boundaries, KnuthBendix.letters(Al)[2:2:end], rels, rws)
+    return SurfaceGroup(genus, boundaries, [Al[i] for i in 2:2:length(Al)], rels, rws)
 end
 
 rewriting(S::SurfaceGroup) = S.rws
diff --git a/src/aut_groups/sautFn.jl b/src/aut_groups/sautFn.jl
index 4e86a37..19e5f45 100644
--- a/src/aut_groups/sautFn.jl
+++ b/src/aut_groups/sautFn.jl
@@ -4,8 +4,8 @@ include("gersten_relations.jl")
 function SpecialAutomorphismGroup(F::FreeGroup; ordering = KnuthBendix.LenLex, kwargs...)
 
     n = length(alphabet(F)) ÷ 2
-    A, rels = gersten_relations(n, commutative = false)
-    S = KnuthBendix.letters(A)[1:2(n^2-n)]
+    A, rels = gersten_relations(n, commutative=false)
+    S = [A[i] for i in 1:2:length(A)]
 
     maxrules = 1000*n
 
diff --git a/src/autgroups.jl b/src/autgroups.jl
index 696270a..8b78223 100644
--- a/src/autgroups.jl
+++ b/src/autgroups.jl
@@ -144,7 +144,7 @@ end
 
 function Base.getindex(lm::LettersMap, i::Integer)
     # here i is an index of an alphabet
-    @boundscheck 1 ≤ i ≤ length(KnuthBendix.letters(lm.A))
+    @boundscheck 1 ≤ i ≤ length(lm.A)
 
     if !haskey(lm.indices_map, i)
         img = if haskey(lm.indices_map, inv(lm.A, i))
diff --git a/src/types.jl b/src/types.jl
index a96e5dc..289bf55 100644
--- a/src/types.jl
+++ b/src/types.jl
@@ -153,8 +153,7 @@ struct FreeGroup{T,O} <: AbstractFPGroup
 
     function FreeGroup(gens, ordering::KnuthBendix.WordOrdering)
         @assert length(gens) == length(unique(gens))
-        L = KnuthBendix.letters(alphabet(ordering))
-        @assert all(l -> l in L, gens)
+        @assert all(l -> l in alphabet(ordering), gens)
         return new{eltype(gens),typeof(ordering)}(gens, ordering)
     end
 end
@@ -163,12 +162,11 @@ FreeGroup(gens, A::Alphabet) = FreeGroup(gens, KnuthBendix.LenLex(A))
 
 function FreeGroup(A::Alphabet)
     @boundscheck @assert all(
-        KnuthBendix.hasinverse(l, A) for l in KnuthBendix.letters(A)
+        KnuthBendix.hasinverse(l, A) for l in A
     )
-    ltrs = KnuthBendix.letters(A)
-    gens = Vector{eltype(ltrs)}()
-    invs = Vector{eltype(ltrs)}()
-    for l in ltrs
+    gens = Vector{eltype(A)}()
+    invs = Vector{eltype(A)}()
+    for l in A
         l ∈ invs && continue
         push!(gens, l)
         push!(invs, inv(A, l))
diff --git a/test/AutSigma3.jl b/test/AutSigma3.jl
index 475fb57..9977b7f 100644
--- a/test/AutSigma3.jl
+++ b/test/AutSigma3.jl
@@ -9,10 +9,10 @@
         pauts = let p = perm"(1,3,5)(2,4,6)"
             [Groups.PermRightAut(p^i) for i in 0:2]
         end
-        T = eltype(KnuthBendix.letters(alphabet(autπ₁Σ)))
+        T = eltype(alphabet(autπ₁Σ))
         S = eltype(pauts)
 
-        A = Alphabet(Union{T,S}[KnuthBendix.letters(alphabet(autπ₁Σ)); pauts])
+        A = Alphabet(Union{T,S}[alphabet(autπ₁Σ)...; pauts])
 
         autG = AutomorphismGroup(
             π₁Σ,
@@ -27,9 +27,7 @@
     Al = alphabet(autπ₁Σ)
     S = [gens(autπ₁Σ); inv.(gens(autπ₁Σ))]
 
-    sautFn = let ltrs = KnuthBendix.letters(Al)
-        parent(first(ltrs).autFn_word)
-    end
+    sautFn = parent(Al[1].autFn_word)
 
     τ = Groups.rotation_element(sautFn)