From fefb2130612bc93690bf023f1458e107e3196169 Mon Sep 17 00:00:00 2001
From: Max Horn <max@quendi.de>
Date: Tue, 1 Jun 2021 00:36:53 +0200
Subject: [PATCH] Revise printing of IsPlistMatrixRep

This fixes printing of 0 x n matrices
---
 lib/matobjplist.gi                      |  9 ++-------
 tst/testinstall/MatrixObj/Matrix.tst    |  8 ++++----
 tst/testinstall/MatrixObj/NewMatrix.tst | 14 +++++++-------
 3 files changed, 13 insertions(+), 18 deletions(-)

diff --git a/lib/matobjplist.gi b/lib/matobjplist.gi
index 8df450c39f2..c03b8d14f62 100644
--- a/lib/matobjplist.gi
+++ b/lib/matobjplist.gi
@@ -748,14 +748,9 @@ InstallMethod( Display, "for a plist matrix", [ IsPlistMatrixRep ],
     local i;
     Print("<");
     if not IsMutable(m) then Print("immutable "); fi;
-    Print(NrRows(m),"x",NrCols(m),"-matrix over ",m![BDPOS],":\n");
+    Print(NrRows(m),"x",NrCols(m),"-matrix over ",m![BDPOS],": [\n");
     for i in [1..NrRows(m)] do
-        if i = 1 then
-            Print("[");
-        else
-            Print(" ");
-        fi;
-        Print(m![ROWSPOS][i],"\n");
+        Print(" ",m![ROWSPOS][i],"\n");
     od;
     Print("]>\n");
   end );
diff --git a/tst/testinstall/MatrixObj/Matrix.tst b/tst/testinstall/MatrixObj/Matrix.tst
index dcf299f0e8f..eb473847c13 100644
--- a/tst/testinstall/MatrixObj/Matrix.tst
+++ b/tst/testinstall/MatrixObj/Matrix.tst
@@ -4,8 +4,8 @@ gap> START_TEST("Matrix.tst");
 gap> m := Matrix( [[1,2],[3,4]] );
 <2x2-matrix over Rationals>
 gap> Display(m);
-<2x2-matrix over Rationals:
-[[ 1, 2 ]
+<2x2-matrix over Rationals: [
+ [ 1, 2 ]
  [ 3, 4 ]
 ]>
 
@@ -34,8 +34,8 @@ gap> Display(m);
 gap> m := Matrix( IsPlistMatrixRep, GF(2), [[1,2],[3,4]] * Z(2) );
 <2x2-matrix over GF(2)>
 gap> Display(m);
-<2x2-matrix over GF(2):
-[[ Z(2)^0, 0*Z(2) ]
+<2x2-matrix over GF(2): [
+ [ Z(2)^0, 0*Z(2) ]
  [ Z(2)^0, 0*Z(2) ]
 ]>
 
diff --git a/tst/testinstall/MatrixObj/NewMatrix.tst b/tst/testinstall/MatrixObj/NewMatrix.tst
index 250f68f3fca..96bc83fb57c 100644
--- a/tst/testinstall/MatrixObj/NewMatrix.tst
+++ b/tst/testinstall/MatrixObj/NewMatrix.tst
@@ -1,23 +1,23 @@
 # IsPlistMatrixRep
 gap> NewMatrix(IsPlistMatrixRep, Integers, 3, [ ] ); Display(last);
 <0x3-matrix over Integers>
-<0x3-matrix over Integers:
+<0x3-matrix over Integers: [
 ]>
 gap> NewMatrix(IsPlistMatrixRep, Integers, 3, [ 1, 2, 3 ] ); Display(last);
 <1x3-matrix over Integers>
-<1x3-matrix over Integers:
-[[ 1, 2, 3 ]
+<1x3-matrix over Integers: [
+ [ 1, 2, 3 ]
 ]>
 gap> NewMatrix(IsPlistMatrixRep, Integers, 3, [ 1, 2, 3, 4, 5, 6 ] ); Display(last);
 <2x3-matrix over Integers>
-<2x3-matrix over Integers:
-[[ 1, 2, 3 ]
+<2x3-matrix over Integers: [
+ [ 1, 2, 3 ]
  [ 4, 5, 6 ]
 ]>
 gap> NewMatrix(IsPlistMatrixRep, Integers, 3, [ [1, 2, 3], [4, 5, 6] ] ); Display(last);
 <2x3-matrix over Integers>
-<2x3-matrix over Integers:
-[[ 1, 2, 3 ]
+<2x3-matrix over Integers: [
+ [ 1, 2, 3 ]
  [ 4, 5, 6 ]
 ]>