Add alignment rule for LaTeX tables (#13)

README.md

@@ -65,7 +65,7 @@ variant `:EasyAlign!`) for visual mode.
 
 An *alignment rule* is a predefined set of options for common alignment tasks,
 which is identified by a single character, *DELIMITER KEY*, such as `<space>`,
-`=`, `:`, `.`, `|`, and `,`.
+`=`, `:`, `.`, `|`, `&`, and `,`.
 
 Think of it as a shortcut. Instead of writing regular expression and setting
 several options, you can just type in a single character.
@@ -95,7 +95,7 @@ With the mapping, you can align selected lines of text with only a few keystroke
     - `-`         Around the last occurrences of delimiters (`-1`)
     - `-2`        Around the second to last occurrences of delimiters
     - ...
-1. Delimiter key (a single keystroke; `<space>`, `=`, `:`, `.`, `|`, `,`)
+1. Delimiter key (a single keystroke; `<space>`, `=`, `:`, `.`, `|`, `&`, `,`)
 
 Alignment rules for the following delimiters have been defined to meet the most needs.
 
@@ -106,6 +106,7 @@ Alignment rules for the following delimiters have been defined to meet the most
 | `:`           | Suitable for formatting JSON or YAML                                 |
 | `.`           | Multi-line method chaining                                           |
 | `,`           | Multi-line method arguments                                          |
+| `&`           | LaTeX tables (matches `&` and `\\`)                                  |
 | &#124;        | Table markdown                                                       |
 
 You can override these default rules or define your own rules with

autoload/easy_align.vim

@@ -34,6 +34,8 @@ let s:easy_align_delimiters_default = {
 \  ',': { 'pattern': ',',  'left_margin': 0, 'right_margin': 1, 'stick_to_left': 1 },
 \  '|': { 'pattern': '|',  'left_margin': 1, 'right_margin': 1, 'stick_to_left': 0 },
 \  '.': { 'pattern': '\.', 'left_margin': 0, 'right_margin': 0, 'stick_to_left': 0 },
+\  '&': { 'pattern': '\\\@<!&\|\\\\',
+\                          'left_margin': 1, 'right_margin': 1, 'stick_to_left': 0 },
 \  '{': { 'pattern': '(\@<!{',
 \                          'left_margin': 1, 'right_margin': 1, 'stick_to_left': 0 },
 \  '}': { 'pattern': '}',  'left_margin': 1, 'right_margin': 0, 'stick_to_left': 0 }

doc/easy_align.txt

@@ -50,6 +50,7 @@ With this mapping, you can align selected lines of text with a few keystrokes.
     :        Suitable for formatting JSON or YAML
     .        Multi-line method chaining
     ,        Multi-line method arguments. CSV.
+    &        LaTeX tables (matches & and \\)
     |        Table markdown
 
     (You can override these default rules or define your own rules with

test/tex.vader

@@ -0,0 +1,98 @@
+# http://en.wikibooks.org/wiki/LaTeX/Tables
+Execute:
+  let g:easy_align_delimiters = {}
+
+Given tex (table with escaped &):
+  \begin{tabular}{ l c r }
+    1&2&3\\
+    44&55&66\\
+    777&8\&8&999\\
+  \end{tabular}
+
+Do (Align around all &s and \\s):
+  vip\<Enter>*&
+
+Expect tex:
+  \begin{tabular}{ l c r }
+    1   & 2    & 3   \\
+    44  & 55   & 66  \\
+    777 & 8\&8 & 999 \\
+  \end{tabular}
+
+Do (right-align with explicit ignore_unmatched):
+  vip\<Enter>\<Enter>\<C-U>\<C-U>*&
+
+Expect tex:
+  \begin{tabular}{ l c r }
+      1 &    2 &   3 \\
+     44 &   55 &  66 \\
+    777 & 8\&8 & 999 \\
+  \end{tabular}
+
+Do (center-align with explicit ignore_unmatched):
+  vip\<Enter>\<Enter>\<Enter>\<C-U>\<C-U>*&
+
+Expect tex:
+  \begin{tabular}{ l c r }
+     1  &  2   &  3  \\
+    44  &  55  & 66  \\
+    777 & 8\&8 & 999 \\
+  \end{tabular}
+
+Given tex (simple table with \hline):
+  \begin{tabular}{ l c r }
+    1&2&3\\ \hline
+    44&55&66\\ \hline
+    777&8\&&999\\ \hline
+  \end{tabular}
+
+Do:
+  vip\<Enter>*&
+
+Expect tex:
+  \begin{tabular}{ l c r }
+    1   & 2   & 3   \\ \hline
+    44  & 55  & 66  \\ \hline
+    777 & 8\& & 999 \\ \hline
+  \end{tabular}
+
+Given tex (table with lines w/o &s):
+  \begin{tabular}{|r|l|}
+    \hline
+    7C0 & hexadecimal \\
+    3700&octal \\ \cline{2-2}
+    1111100000 & binary \\
+    \hline \hline
+    1984 & decimal \\
+    \hline
+  \end{tabular}
+
+Do (left-align*):
+  vip\<Enter>*&
+
+Expect tex:
+  \begin{tabular}{|r|l|}
+    \hline
+    7C0        & hexadecimal \\
+    3700       & octal       \\ \cline{2-2}
+    1111100000 & binary      \\
+    \hline \hline
+    1984       & decimal     \\
+    \hline
+  \end{tabular}
+
+Do(left-align* and right-align around 2nd):
+  vip\<Enter>*&
+  gv\<Enter>\<Enter>2&
+
+Expect tex:
+  \begin{tabular}{|r|l|}
+    \hline
+    7C0        & hexadecimal \\
+    3700       &       octal \\ \cline{2-2}
+    1111100000 &      binary \\
+    \hline \hline
+    1984       &     decimal \\
+    \hline
+  \end{tabular}
+