Overhaul table row parsing (#288)
Fix table-parsing bug w/ w/s following an escaped pipe
diff --git a/.travis.yml b/.travis.yml
index a5026d9..dbb7c4a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,7 +1,7 @@
language: dart
dart:
- - 2.2.0
+ - 2.6.0
- dev
dart_task:
diff --git a/lib/src/block_parser.dart b/lib/src/block_parser.dart
index b488093..ca6102f 100644
--- a/lib/src/block_parser.dart
+++ b/lib/src/block_parser.dart
@@ -841,10 +841,6 @@
/// Parses tables.
class TableSyntax extends BlockSyntax {
- static final _pipePattern = RegExp(r'\s*\|\s*');
- static final _openingPipe = RegExp(r'^\|\s*');
- static final _closingPipe = RegExp(r'\s*\|$');
-
@override
bool get canEndBlock => false;
@@ -897,8 +893,23 @@
}
List<String> parseAlignments(String line) {
- line = line.replaceFirst(_openingPipe, '').replaceFirst(_closingPipe, '');
- return line.split('|').map((column) {
+ var startIndex = _walkPastOpeningPipe(line);
+
+ var endIndex = line.length - 1;
+ while (endIndex > 0) {
+ var ch = line.codeUnitAt(endIndex);
+ if (ch == $pipe) {
+ endIndex--;
+ break;
+ }
+ if (ch != $space && ch != $tab) {
+ break;
+ }
+ endIndex--;
+ }
+
+ // Optimization: We walk [line] too many times. One lap should do it.
+ return line.substring(startIndex, endIndex + 1).split('|').map((column) {
column = column.trim();
if (column.startsWith(':') && column.endsWith(':')) return 'center';
if (column.startsWith(':')) return 'left';
@@ -907,29 +918,70 @@
}).toList();
}
+ /// Parses a table row at the current line into a table row element, with
+ /// parsed table cells.
+ ///
+ /// [alignments] is used to annotate an alignment on each cell, and
+ /// [cellType] is used to declare either "td" or "th" cells.
Element parseRow(
BlockParser parser, List<String> alignments, String cellType) {
- var line = parser.current
- .replaceFirst(_openingPipe, '')
- .replaceFirst(_closingPipe, '');
- var cells = line.split(_pipePattern);
- parser.advance();
- var row = <Element>[];
- String preCell;
+ var line = parser.current;
+ var cells = <String>[];
+ var index = _walkPastOpeningPipe(line);
+ var cellBuffer = StringBuffer();
- for (var cell in cells) {
- if (preCell != null) {
- cell = preCell + cell;
- preCell = null;
+ while (true) {
+ if (index >= line.length) {
+ // This row ended without a trailing pipe, which is fine.
+ cells.add(cellBuffer.toString().trimRight());
+ cellBuffer.clear();
+ break;
}
- if (cell.endsWith('\\')) {
- preCell = cell.substring(0, cell.length - 1) + '|';
- continue;
+ var ch = line.codeUnitAt(index);
+ if (ch == $backslash) {
+ if (index == line.length - 1) {
+ // A table row ending in a backslash is not well-specified, but it
+ // looks like GitHub just allows the character as part of the text of
+ // the last cell.
+ cellBuffer.writeCharCode(ch);
+ cells.add(cellBuffer.toString().trimRight());
+ cellBuffer.clear();
+ break;
+ }
+ var escaped = line.codeUnitAt(index + 1);
+ if (escaped == $pipe) {
+ // GitHub Flavored Markdown has a strange bit here; the pipe is to be
+ // escaped before any other inline processing. One consequence, for
+ // example, is that "| `\|` |" should be parsed as a cell with a code
+ // element with text "|", rather than "\|". Most parsers are not
+ // compliant with this corner, but this is what is specified, and what
+ // GitHub does in practice.
+ cellBuffer.writeCharCode(escaped);
+ } else {
+ // The [InlineParser] will handle the escaping.
+ cellBuffer.writeCharCode(ch);
+ cellBuffer.writeCharCode(escaped);
+ }
+ index += 2;
+ } else if (ch == $pipe) {
+ cells.add(cellBuffer.toString().trimRight());
+ cellBuffer.clear();
+ // Walk forward past any whitespace which leads the next cell.
+ index++;
+ index = _walkPastWhitespace(line, index);
+ if (index >= line.length) {
+ // This row ended with a trailing pipe.
+ break;
+ }
+ } else {
+ cellBuffer.writeCharCode(ch);
+ index++;
}
-
- var contents = UnparsedContent(cell);
- row.add(Element(cellType, [contents]));
}
+ parser.advance();
+ var row = [
+ for (var cell in cells) Element(cellType, [UnparsedContent(cell)])
+ ];
for (var i = 0; i < row.length && i < alignments.length; i++) {
if (alignments[i] == null) continue;
@@ -938,6 +990,43 @@
return Element('tr', row);
}
+
+ /// Walks past whitespace in [line] starting at [index].
+ ///
+ /// Returns the index of the first non-whitespace character.
+ int _walkPastWhitespace(String line, int index) {
+ while (index < line.length) {
+ var ch = line.codeUnitAt(index);
+ if (ch != $space && ch != $tab) {
+ break;
+ }
+ index++;
+ }
+ return index;
+ }
+
+ /// Walks past the opening pipe (and any whitespace that surrounds it) in
+ /// [line].
+ ///
+ /// Returns the index of the first non-whitespace character after the pipe.
+ /// If no opening pipe is found, this just returns the index of the first
+ /// non-whitespace character.
+ int _walkPastOpeningPipe(String line) {
+ var index = 0;
+ while (index < line.length) {
+ var ch = line.codeUnitAt(index);
+ if (ch == $pipe) {
+ index++;
+ index = _walkPastWhitespace(line, index);
+ }
+ if (ch != $space && ch != $tab) {
+ // No leading pipe.
+ break;
+ }
+ index++;
+ }
+ return index;
+ }
}
/// Parses paragraphs of regular text.
diff --git a/pubspec.yaml b/pubspec.yaml
index 3781638..a5c9de1 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -8,7 +8,7 @@
markdown:
environment:
- sdk: '>=2.2.0 <3.0.0'
+ sdk: '>=2.6.0 <3.0.0'
dependencies:
args: ^1.0.0
diff --git a/test/extensions/tables.unit b/test/extensions/tables.unit
index ab069b4..1a1fa11 100644
--- a/test/extensions/tables.unit
+++ b/test/extensions/tables.unit
@@ -84,3 +84,10 @@
<<<
<table><thead><tr><th>Name</th><th>Character</th></tr></thead><tbody><tr><td>Backtick</td><td>`</td></tr><tr><td>Pipe</td><td>|</td></tr></tbody></table>
+>>> escape pipe, preserve trailing whitespace
+| Name | Character |
+| --- | --- |
+| Pipe | \| abcdef |
+
+<<<
+<table><thead><tr><th>Name</th><th>Character</th></tr></thead><tbody><tr><td>Pipe</td><td>| abcdef</td></tr></tbody></table>
