From 265e7a2da29e6e53e19d5c53404935e33bb47c52 Mon Sep 17 00:00:00 2001
From: Jeremy Ruston <jeremy@jermolene.com>
Date: Tue, 7 Apr 2020 16:16:29 +0100
Subject: [PATCH] Add support for \dir pragma

---
 core/modules/parsers/wikiparser/rules/dir.js  | 51 +++++++++++++++++++
 core/modules/parsers/wikiparser/wikiparser.js |  3 +-
 .../tiddlers/Right-To-Left Languages.tid      | 11 ++++
 editions/tw5.com/tiddlers/concepts/Pragma.tid |  6 ++-
 4 files changed, 69 insertions(+), 2 deletions(-)
 create mode 100644 core/modules/parsers/wikiparser/rules/dir.js
 create mode 100644 editions/tw5.com/tiddlers/Right-To-Left Languages.tid

diff --git a/core/modules/parsers/wikiparser/rules/dir.js b/core/modules/parsers/wikiparser/rules/dir.js
new file mode 100644
index 000000000..e30fe7a47
--- /dev/null
+++ b/core/modules/parsers/wikiparser/rules/dir.js
@@ -0,0 +1,51 @@
+/*\
+title: $:/core/modules/parsers/wikiparser/rules/dir.js
+type: application/javascript
+module-type: wikirule
+
+Wiki pragma rule for specifying text direction
+
+```
+\dir rtl
+\dir ltr
+\dir auto
+```
+
+\*/
+(function(){
+
+/*jslint node: true, browser: true */
+/*global $tw: false */
+"use strict";
+
+exports.name = "dir";
+exports.types = {pragma: true};
+
+/*
+Instantiate parse rule
+*/
+exports.init = function(parser) {
+	this.parser = parser;
+	// Regexp to match
+	this.matchRegExp = /^\\dir[^\S\n]*(\S+)\r?\n/mg;
+};
+
+/*
+Parse the most recent match
+*/
+exports.parse = function() {
+	var self = this;
+	// Move past the pragma invocation
+	this.parser.pos = this.matchRegExp.lastIndex;
+	// Parse tree nodes to return
+	return [{
+		type: "element",
+		tag: this.parser.parseAsInline ? "span" : "div",
+		attributes: {
+			dir: {type: "string", value: this.match[1]}
+		},
+		children: []
+	}];
+};
+
+})();
diff --git a/core/modules/parsers/wikiparser/wikiparser.js b/core/modules/parsers/wikiparser/wikiparser.js
index 673176038..5ef49b814 100644
--- a/core/modules/parsers/wikiparser/wikiparser.js
+++ b/core/modules/parsers/wikiparser/wikiparser.js
@@ -27,6 +27,7 @@ Attributes are stored as hashmaps of the following objects:
 
 var WikiParser = function(type,text,options) {
 	this.wiki = options.wiki;
+	this.parseAsInline = options.parseAsInline;
 	var self = this;
 	// Check for an externally linked tiddler
 	if($tw.browser && (text || "") === "" && options._canonical_uri) {
@@ -63,7 +64,7 @@ var WikiParser = function(type,text,options) {
 	this.tree = [];
 	var topBranch = this.parsePragmas();
 	// Parse the text into inline runs or blocks
-	if(options.parseAsInline) {
+	if(this.parseAsInline) {
 		topBranch.push.apply(topBranch,this.parseInlineRun());
 	} else {
 		topBranch.push.apply(topBranch,this.parseBlocks());
diff --git a/editions/tw5.com/tiddlers/Right-To-Left Languages.tid b/editions/tw5.com/tiddlers/Right-To-Left Languages.tid
new file mode 100644
index 000000000..67c02cfb8
--- /dev/null
+++ b/editions/tw5.com/tiddlers/Right-To-Left Languages.tid	
@@ -0,0 +1,11 @@
+created: 20200406151830903
+modified: 20200406152521698
+title: Right-To-Left Languages
+type: text/vnd.tiddlywiki
+
+<<.from-version "5.1.22">> The [[language plugins|Languages]] in TiddlyWiki's plugin library apply the appropriate [["right-to-left" setting|https://www.w3.org/International/questions/qa-html-dir]] to the entire document. To set the right to left setting independently for an individual tiddler, use the `\dir` [[pragma|Pragma]] at the top of the tiddler:
+
+```
+\dir rtl
+This text will be displayed with right-to-left formatting
+```
diff --git a/editions/tw5.com/tiddlers/concepts/Pragma.tid b/editions/tw5.com/tiddlers/concepts/Pragma.tid
index 3adc97954..5e4ff3302 100644
--- a/editions/tw5.com/tiddlers/concepts/Pragma.tid
+++ b/editions/tw5.com/tiddlers/concepts/Pragma.tid
@@ -1,5 +1,5 @@
 created: 20150219175930000
-modified: 20180928145730028
+modified: 20200406151829696
 tags: Concepts
 title: Pragma
 type: text/vnd.tiddlywiki
@@ -18,3 +18,7 @@ The following pragmas are available:
 : <<.from-version "5.1.15">> Control whether whitespace is trimmed from the start and end of text runs (the default is ''notrim''). This setting can be useful when the whitespace generated by linebreaks disturbs formatting
 ;`\import <filter-expression>`
 : <<.from-version "5.1.18">> for importing macro definitions from tiddlers identified by a filter expression
+;`\dir ltr`
+;`\dir rtl`
+;`\dir auto`
+: <<.from-version "5.1.22">> for setting the text direction of a tiddler -- see [[Right-To-Left Languages]].