maths · EJMFarrow · Jul 22, 2026 · Aug 7, 2026 · Aug 7, 2026 · Aug 7, 2026
diff --git a/lang/en/qtype_stack.php b/lang/en/qtype_stack.php
@@ -1128,6 +1128,7 @@
 $string['stackBlock_ascii_answer_format'] = 'The answer attribute of the ASCII block must be in the format \"[ans1,extractor,filter],[ans2,extractor,filter],...\".';
 $string['stackBlock_ascii_unknown_param'] = 'Unknown parameter \'{$a}\' for the ASCII block.';
 $string['stackBlock_ascii_param'] = 'Valid parameters are: {$a->param}.';
+$string['stackBlock_ascii_incorrect_alignment'] = 'The output must be aligned left or right.';
 
 $string['stackBlock_extractor_targetinput_required'] = 'You must define the targetinput for the extractor block to send the answer to.';
 $string['stackBlock_extractor_type_required'] = 'You must define the type of extractor you want to use.';

diff --git a/stack/cas/castext2/blocks/ascii.block.php b/stack/cas/castext2/blocks/ascii.block.php
@@ -108,6 +108,13 @@ public function compile($format, $options): ?MP_Node {
         $height = $existsuserheight ? $xpars['height'] : "400px";
         $xpars['width'] = $width;
         $xpars['height'] = $height;
+        $direction = stack_get_system_direction();
+        if (($xpars['align'] ?? null) === 'left') {
+            $direction = 'ltr';
+        } else if (($xpars['align'] ?? null) === 'right') {
+            $direction = 'rtl';
+        }
+        $xpars['stack-ascii-direction'] = $direction;
 
         // Set a title.
         $xpars['title'] = 'STACK ASCII ///ASCII_COUNT///';
@@ -287,22 +294,29 @@ public function validate(
             $valid    = false;
             $err[] = stack_string('stackBlock_ascii_underdefined_dimension');
         }
+        if (
+            array_key_exists('align', $this->params) && !in_array($this->params['align'], ['left', 'right'])
+        ) {
+            $valid = false;
+            $err[] = stack_string('stackBlock_ascii_incorrect_alignment');
+        }
 
         // Check that only valid parameters are passed to block header.
         $valids = null;
         foreach ($this->params as $key => $value) {
             if (
                 $key !== 'width' &&
                 $key !== 'height' &&
-                $key !== 'aspect-ratio' &
+                $key !== 'aspect-ratio' &&
+                $key !== 'align' &&
                 $key !== 'input' &&
                 $key !== 'hidden'
             ) {
                 $err[] = stack_string('stackBlock_ascii_unknown_param', $key);
                 $valid    = false;
                 if ($valids === null) {
                     $valids = [
-                        'width', 'height', 'aspect-ratio', 'input', 'hidden',
+                        'width', 'height', 'aspect-ratio', 'align', 'input', 'hidden',
                     ];
                     $err[] = stack_string('stackBlock_ascii_param', [
                         'param' => implode(', ', $valids),

diff --git a/stack/cas/castext2/blocks/iframe.block.php b/stack/cas/castext2/blocks/iframe.block.php
@@ -184,8 +184,15 @@ public function postprocess(
         $code = '<?xml version="1.0" encoding="UTF-8"?>' . "\n";
         $code .= '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"' .
             ' "http://www.w3.org/TR/xhtml1/DTD/strict.dtd">' . "\n";
+        $directionattribute = '';
+        if (isset($parameters['stack-ascii-direction'])) {
+            $direction = $parameters['stack-ascii-direction'];
+            if ($direction === 'ltr' || $direction === 'rtl') {
+                $directionattribute = ' dir="' . $direction . '"';
+            }
+        }
         $code .= '<html xmlns="http://www.w3.org/TR/xhtml1/strict" lang="' .
-            stack_get_system_language() . '">';
+            stack_get_system_language() . '"' . $directionattribute . '>';
         // Include a title to help JS debugging.
         $code .= '<head><title>' . $title . '</title>';
         $code .= $style;

diff --git a/styles.css b/styles.css
@@ -1247,7 +1247,6 @@ table.HELM_table th:last-child {
 .que.stack .equivinput,
 .que.stack .varmatrixinput,
 .que.stack .matrixtable,
-.que.stack .freetextinput,
 /* Question authoring form */
 #page-question-type-stack textarea#id_questionvariables,
 #page-question-type-stack input#id_variantsselectionseed,

diff --git a/tests/ascii_block_test.php b/tests/ascii_block_test.php
@@ -23,6 +23,7 @@
 
 namespace qtype_stack;
 
+use api\util\StackIframeHolder;
 use castext2_evaluatable;
 use qtype_stack_testcase;
 use stack_cas_session2;
@@ -60,6 +61,30 @@ private function get_string_items(\MP_List $compiled): array {
         return $strings;
     }
 
+    /**
+     * Render an ASCII block and return the generated iframe document.
+     * @param string $raw
+     * @return string
+     */
+    private function render_ascii_iframe_content(string $raw): string {
+        stack_cas_castext2_iframe::register_counter('///IFRAME_COUNT///');
+        StackIframeHolder::$islibrary = true;
+        StackIframeHolder::$iframes = [];
+
+        try {
+            $at1 = castext2_evaluatable::make_from_source($raw, 'test-case');
+            $session = new stack_cas_session2([$at1]);
+            $session->instantiate();
+            $at1->apply_placeholder_holder($at1->get_rendered());
+
+            $this->assertCount(1, StackIframeHolder::$iframes);
+            return StackIframeHolder::$iframes[0][1];
+        } finally {
+            StackIframeHolder::$islibrary = false;
+            StackIframeHolder::$iframes = [];
+        }
+    }
+
     public function test_basic_ascii_block(): void {
         stack_cas_castext2_iframe::register_counter('///IFRAME_COUNT///');
 
@@ -73,6 +98,32 @@ public function test_basic_ascii_block(): void {
         $this->assertEquals($expected, $at1->apply_placeholder_holder($at1->get_rendered()));
     }
 
+    public function test_ascii_iframe_document_uses_system_direction(): void {
+        $iframecontent = $this->render_ascii_iframe_content('[[ascii input="ans1"]][[/ascii]]');
+
+        $this->assertStringContainsString(
+            '<html xmlns="http://www.w3.org/TR/xhtml1/strict" lang="' . stack_get_system_language() .
+                '" dir="' . stack_get_system_direction() . '">',
+            $iframecontent
+        );
+        $this->assertStringContainsString('<div class="container row asciimath" id="asciiContainerRow"', $iframecontent);
+        $this->assertStringNotContainsString('id="asciiContainerRow" dir=', $iframecontent);
+    }
+
+    public function test_ascii_align_parameter_overrides_iframe_document_direction(): void {
+        $leftcontent = $this->render_ascii_iframe_content('[[ascii input="ans1" align="left"]][[/ascii]]');
+        $rightcontent = $this->render_ascii_iframe_content('[[ascii input="ans1" align="right"]][[/ascii]]');
+
+        $this->assertStringContainsString(
+            '<html xmlns="http://www.w3.org/TR/xhtml1/strict" lang="' . stack_get_system_language() . '" dir="ltr">',
+            $leftcontent
+        );
+        $this->assertStringContainsString(
+            '<html xmlns="http://www.w3.org/TR/xhtml1/strict" lang="' . stack_get_system_language() . '" dir="rtl">',
+            $rightcontent
+        );
+    }
+
     public function test_ascii_block_with_filter_and_extractor_children(): void {
         stack_cas_castext2_iframe::register_counter('///IFRAME_COUNT///');
 
@@ -102,6 +153,7 @@ public function test_ascii_compile_adds_default_filter_and_input_request(): void
         $xpars = json_decode($compiled->items[1]->value, true);
         $this->assertEquals('100%', $xpars['width']);
         $this->assertEquals('400px', $xpars['height']);
+        $this->assertEquals(stack_get_system_direction(), $xpars['stack-ascii-direction']);
         $this->assertStringContainsString('STACK ASCII', $xpars['title']);
 
         $strings = $this->get_string_items($compiled);
@@ -131,6 +183,35 @@ public function test_ascii_compile_without_input_parameter_uses_empty_input_requ
         $this->assertStringContainsString($expectedlinkcode, $joined);
     }
 
+    public function test_ascii_align_parameter_sets_document_direction_only(): void {
+        $blockright = new \stack_cas_castext2_ascii(['align' => 'right'], []);
+        $compiledright = $blockright->compile(null, []);
+
+        $this->assertInstanceOf(\MP_List::class, $compiledright);
+
+        $xparsright = json_decode($compiledright->items[1]->value, true);
+        $this->assertEquals('rtl', $xparsright['stack-ascii-direction']);
+        $strings = $this->get_string_items($compiledright);
+        $joined = implode("\n", $strings);
+        $this->assertStringContainsString(
+            '<div class="container row asciimath" id="asciiContainerRow"',
+            $joined
+        );
+        $this->assertStringNotContainsString('algebraic-right', $joined);
+
+        $blockleft = new \stack_cas_castext2_ascii(['align' => 'left'], []);
+        $compiledleft = $blockleft->compile(null, []);
+        $this->assertInstanceOf(\MP_List::class, $compiledleft);
+        $xparsleft = json_decode($compiledleft->items[1]->value, true);
+        $this->assertEquals('ltr', $xparsleft['stack-ascii-direction']);
+        $joinedleft = implode("\n", $this->get_string_items($compiledleft));
+        $this->assertStringContainsString(
+            '<div class="container row asciimath" id="asciiContainerRow"',
+            $joinedleft
+        );
+        $this->assertStringNotContainsString('algebraic-right', $joinedleft);
+    }
+
     public function test_ascii_compile_uses_child_filter_and_extractor_operations(): void {
         $filter = new \stack_cas_castext2_filter([
             'type' => 'markdown',
@@ -254,6 +335,22 @@ public function test_ascii_aspect_ratio_dimension_rules(): void {
         $this->assertEquals(stack_string('stackBlock_ascii_underdefined_dimension'), $atunder->get_errors());
     }
 
+    public function test_ascii_validate_alignment_parameter(): void {
+        $validleft = '[[ascii input="ans1" align="left"]][[/ascii]]';
+        $validright = '[[ascii input="ans1" align="right"]][[/ascii]]';
+        $invalid = '[[ascii input="ans1" align="center"]][[/ascii]]';
+
+        $atleft = castext2_evaluatable::make_from_source($validleft, 'test-case');
+        $this->assertTrue($atleft->get_valid());
+
+        $atright = castext2_evaluatable::make_from_source($validright, 'test-case');
+        $this->assertTrue($atright->get_valid());
+
+        $atinvalid = castext2_evaluatable::make_from_source($invalid, 'test-case');
+        $this->assertFalse($atinvalid->get_valid());
+        $this->assertEquals(stack_string('stackBlock_ascii_incorrect_alignment'), $atinvalid->get_errors());
+    }
+
     public function test_ascii_unknown_param_rejected(): void {
         $raw = '[[ascii input="ans1" bad_param="x"]][[/ascii]]';
 
@@ -262,7 +359,7 @@ public function test_ascii_unknown_param_rejected(): void {
         $this->assertFalse($at1->get_valid());
         $this->assertStringContainsString(stack_string('stackBlock_ascii_unknown_param', 'bad_param'), $at1->get_errors());
         $this->assertStringContainsString(stack_string('stackBlock_ascii_param', [
-            'param' => 'width, height, aspect-ratio, input, hidden',
+            'param' => 'width, height, aspect-ratio, align, input, hidden',
         ]), $at1->get_errors());
     }
 }
diff --git a/vle_specific.php b/vle_specific.php
@@ -370,3 +370,10 @@ function stack_fetch_included_content(string $url) {
 function stack_get_system_language(): string {
     return current_language();
 }
+
+/**
+ * Fetches the direction of the current VLE UI language.
+ */
+function stack_get_system_direction(): string {
+    return function_exists('right_to_left') && right_to_left() ? 'rtl' : 'ltr';
+}