From c54b471aa1ad8b6f8c982bbc53c4c43133677159 Mon Sep 17 00:00:00 2001
From: Tom de Geus <tom@geus.me>
Date: Thu, 8 Feb 2024 10:30:03 +0100
Subject: [PATCH] Minor bugfix table align: empty trailing column

---
 .pre-commit-config.yaml |  6 +++---
 tests/test_align.py     | 32 ++++++++++++++++++++++++--------
 texplain/__init__.py    |  6 +++++-
 3 files changed, 32 insertions(+), 12 deletions(-)

diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index b6ae599..2db7c79 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -8,7 +8,7 @@ repos:
   - id: check-toml
   - id: debug-statements
 - repo: https://github.com/macisamuele/language-formatters-pre-commit-hooks
-  rev: v2.11.0
+  rev: v2.12.0
   hooks:
   - id: pretty-format-yaml
     args: [--preserve-quotes, --autofix, --indent, '2']
@@ -25,7 +25,7 @@ repos:
   - id: rst-directive-colons
   - id: rst-inline-touching-normal
 - repo: https://github.com/psf/black
-  rev: 23.12.0
+  rev: 24.1.1
   hooks:
   - id: black
     args: [--safe, --quiet, --line-length=100]
@@ -44,7 +44,7 @@ repos:
   - id: pyupgrade
     args: [--py36-plus]
 - repo: https://github.com/PyCQA/flake8
-  rev: 6.1.0
+  rev: 7.0.0
   hooks:
   - id: flake8
     args: ["--max-line-length=100", "--ignore=E203", "--per-file-ignores=tests/*.py:E501"]
diff --git a/tests/test_align.py b/tests/test_align.py
index 677ea79..3ee63e5 100644
--- a/tests/test_align.py
+++ b/tests/test_align.py
@@ -17,7 +17,6 @@ def test_tabular_align_no_newline():
     40 & 50 & 60
 \end{tabular}
 """
-
     ret = texplain.indent(text)
     assert ret.strip() == formatted.strip()
 
@@ -34,7 +33,6 @@ def test_tabular_align_empty():
     \@author
 \end{tabular}
 """
-
     ret = texplain.indent(text)
     assert ret.strip() == formatted.strip()
 
@@ -55,7 +53,6 @@ def test_tabular_align_nested():
     \end{tabular}
 }
 """
-
     ret = texplain.indent(text)
     assert ret.strip() == formatted.strip()
 
@@ -75,8 +72,29 @@ def test_tabular_align_empty_leading_column():
     1 & 2   & 3      \\
     4 & 5   & 6
 \end{tabular}
+"""
+    ret = texplain.indent(text)
+    assert ret.strip() == formatted.strip()
+
+
+def test_tabular_align_empty_trailing_column():
+    text = r"""
+\begin{tabular}[t]{ccc}
+& foo & foobar \\
+1 & 2 & \\
+4 & 5 & d \\
+& &
+\end{tabular}
 """
 
+    formatted = r"""
+\begin{tabular}[t]{ccc}
+      & foo & foobar \\
+    1 & 2   &        \\
+    4 & 5   & d      \\
+      &     &
+\end{tabular}
+"""
     ret = texplain.indent(text)
     assert ret.strip() == formatted.strip()
 
@@ -97,7 +115,6 @@ def test_tabular_align_empty_column():
     & 5   & 6
 \end{tabular}
 """
-
     ret = texplain.indent(text)
     assert ret.strip() == formatted.strip()
 
@@ -109,7 +126,8 @@ def test_tabular_overflow():
     Foo & Bar  & Baz   \\
     \midrule
     $a$ & $b = 1000$ & $e$  \\
-    $c'$ & $d = 2$ & $f'$ \\
+    $c'$& $d = 2$ & $f'$ \\
+    a & & \\
     this is a very long column with a lot of text, this is a very long column with a lot of text & this is a very long column with a lot of text, this is a very long column with a lot of text & short \\
     \bottomrule
 \end{tabular}
@@ -122,11 +140,11 @@ def test_tabular_overflow():
     \midrule
     $a$ & $b = 1000$ & $e$ \\
     $c'$ & $d = 2$ & $f'$ \\
+    a & & \\
     this is a very long column with a lot of text, this is a very long column with a lot of text & this is a very long column with a lot of text, this is a very long column with a lot of text & short \\
     \bottomrule
 \end{tabular}
 """
-
     ret = texplain.indent(text)
     assert ret.strip() == formatted.strip()
 
@@ -153,7 +171,6 @@ def test_tabular_math():
     \bottomrule
 \end{tabular}
 """
-
     ret = texplain.indent(text)
     assert ret.strip() == formatted.strip()
 
@@ -180,6 +197,5 @@ def test_tabular_math_empty():
     \bottomrule
 \end{tabular}
 """
-
     ret = texplain.indent(text)
     assert ret.strip() == formatted.strip()
diff --git a/texplain/__init__.py b/texplain/__init__.py
index 1d87d6a..7702425 100644
--- a/texplain/__init__.py
+++ b/texplain/__init__.py
@@ -1174,6 +1174,10 @@ def _align(text: str, placeholders: dict[list[Placeholder]] = {}, maxwidth: int
         ret = ["" for _ in range(np.max(icol) + 1)]
         for j in range(len(line)):
             ret[icol[j]] = line[j]
+        # add empty column if the line ends with "& \\"
+        if len(ret) >= 2:
+            if ret[-2] == "&" and ret[-1] == r"\\":
+                ret.insert(-1, "")
         lines[i] = ret
         cols = max(cols, len(ret))
 
@@ -1204,7 +1208,7 @@ def _align(text: str, placeholders: dict[list[Placeholder]] = {}, maxwidth: int
     # lines too long: no alignment is done
     if sum(col_width) > maxwidth:
         for i in range(1, len(lines) - 1):
-            lines[i] = " ".join(lines[i])
+            lines[i] = " ".join(filter(None, lines[i]))
         return "\n".join(lines)
 
     # align columns if needed