From 829832c896990fedb8c1485e7f3e08f5589f6dbf Mon Sep 17 00:00:00 2001
From: David Gustavsson <david.e.gustavsson@gmail.com>
Date: Sun, 15 Sep 2024 13:39:21 +0200
Subject: [PATCH] Latexify undefined array elements

---
 src/latexarray.jl       |  7 +++++--
 test/latexarray_test.jl | 23 +++++++++++++++++++++++
 2 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/src/latexarray.jl b/src/latexarray.jl
index 66cda996..49eed688 100644
--- a/src/latexarray.jl
+++ b/src/latexarray.jl
@@ -45,9 +45,12 @@ function _latexarray(
                  "}\n"
                 )
 
-    arr = latexraw.(arr; kwargs...)
     for i in rows, j in columns
-        str *= arr[i,j]
+        if isassigned(arr, i, j)
+            str *= latexraw(arr[i,j]; kwargs...)
+        else
+            str *= raw"\cdot"
+        end
         j == last(columns) ? (str *= eol) : (str *= " & ")
     end
 
diff --git a/test/latexarray_test.jl b/test/latexarray_test.jl
index 6012a649..5f51b2dd 100644
--- a/test/latexarray_test.jl
+++ b/test/latexarray_test.jl
@@ -228,3 +228,26 @@ tensor = rand(3,3,3)
 
 tensor = fill(42)
 @test_throws ErrorException("Cannot latexify n-dimensional tensors with n≠1,2") latexify(tensor)
+
+undefarr = Array{Any,2}(undef, 2, 2)
+@test latexify(undefarr) == replace(
+raw"\begin{equation}
+\left[
+\begin{array}{cc}
+\cdot & \cdot \\
+\cdot & \cdot \\
+\end{array}
+\right]
+\end{equation}
+", "\r\n"=>"\n")
+undefarr[1,1] = "x"
+@test latexify(undefarr) == replace(
+raw"\begin{equation}
+\left[
+\begin{array}{cc}
+x & \cdot \\
+\cdot & \cdot \\
+\end{array}
+\right]
+\end{equation}
+", "\r\n"=>"\n")