restructure dot functionality into subpackage

cmd/internal/markov/absorbing.go

@@ -17,8 +17,6 @@ along with this program. If not, see <http://www.gnu.org/licenses/>.
 package markov
 
 import (
-	"math"
-
 	"gonum.org/v1/gonum/graph"
 	"gonum.org/v1/gonum/graph/multi"
 	"gonum.org/v1/gonum/graph/simple"
@@ -139,19 +137,3 @@ func (g *AbsorbingMarkovChain) AdjacencyMatrix() *mat.Dense {
 
 	return a
 }
-
-// NewLine returns a DOT-aware weighted line.
-func (g *AbsorbingMarkovChain) NewLine(from, to graph.Node) graph.Line {
-	e := g.WeightedDirectedGraph.NewWeightedLine(from, to, math.NaN()).(multi.WeightedLine)
-	return &weightedLine{WeightedLine: e}
-}
-
-// NewNode returns a DOT-aware Node.
-func (g *AbsorbingMarkovChain) NewNode() graph.Node {
-	return &Node{Node: g.WeightedDirectedGraph.NewNode()}
-}
-
-// SetLine adds a DOT-aware weighted line to the Markov chain.
-func (g *AbsorbingMarkovChain) SetLine(e graph.Line) {
-	g.WeightedDirectedGraph.SetWeightedLine(e.(*weightedLine))
-}

cmd/internal/markov/dot/markov.go

@@ -0,0 +1,53 @@
+/*
+Copyright © 2025 filifa
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+package dot
+
+import (
+	"math"
+
+	"scm.dairydemon.net/filifa/dptdist/cmd/internal/markov"
+
+	"gonum.org/v1/gonum/graph"
+	"gonum.org/v1/gonum/graph/multi"
+)
+
+// DOTMarkovChain is a graph representing an absorbing Markov chain.
+type DOTMarkovChain struct {
+	*markov.AbsorbingMarkovChain
+}
+
+// NewDOTMarkovChain returns an absorbing Markov chain with no nodes or
+// edges.
+func NewDOTMarkovChain() *DOTMarkovChain {
+	return &DOTMarkovChain{AbsorbingMarkovChain: markov.NewAbsorbingMarkovChain()}
+}
+
+// NewLine returns a DOT-aware weighted line.
+func (g *DOTMarkovChain) NewLine(from, to graph.Node) graph.Line {
+	e := g.AbsorbingMarkovChain.NewWeightedLine(from, to, math.NaN()).(multi.WeightedLine)
+	return &weightedLine{WeightedLine: e}
+}
+
+// NewNode returns a DOT-aware Node.
+func (g *DOTMarkovChain) NewNode() graph.Node {
+	return &Node{Node: g.AbsorbingMarkovChain.NewNode()}
+}
+
+// SetLine adds a DOT-aware weighted line to the Markov chain.
+func (g *DOTMarkovChain) SetLine(e graph.Line) {
+	g.AbsorbingMarkovChain.SetWeightedLine(e.(*weightedLine))
+}

cmd/internal/markov/dot/nodes_edges.go

@@ -14,7 +14,7 @@ GNU General Public License for more details.
 You should have received a copy of the GNU General Public License
 along with this program. If not, see <http://www.gnu.org/licenses/>.
 */
-package markov
+package dot
 
 import (
 	"errors"