io: fix DIGRAPHS_TournamentLineDecoder

Author: james-d-mitchell

data/tourn4.txt

@@ -0,0 +1,4 @@
+000000
+000101
+100010
+100100

gap/io.gi

@@ -1254,6 +1254,7 @@ BindGlobal("DIGRAPHS_TournamentLineDecoder",
 function(func, s)
   local out, pos, n, i, j;
   pos := 0;
+  s := Chomp(s);
   n := (Sqrt(8 * Length(s) + 1) + 1) / 2;
   out := List([1 .. n], x -> []);
   for i in [1 .. n - 1] do

tst/standard/io.tst

@@ -415,6 +415,12 @@ gap> OutNeighbours(gr);
 [ [ 2, 4 ], [  ], [ 1, 2, 4 ], [ 2 ] ]
 gap> gr := TournamentLineDecoder("");
 <immutable empty digraph with 1 vertex>
+gap> fname := Concatenation(DIGRAPHS_Dir(), "/data/tourn4.txt");;
+gap> ReadDigraphs(fname, TournamentLineDecoder);
+[ <immutable digraph with 4 vertices, 6 edges>, 
+  <immutable digraph with 4 vertices, 6 edges>, 
+  <immutable digraph with 4 vertices, 6 edges>, 
+  <immutable digraph with 4 vertices, 6 edges> ]
 
 #  AdjacencyMatrixUpperTriangleLineDecoder
 gap> gr := AdjacencyMatrixUpperTriangleLineDecoder("100101");