Enhancement to directionality heuristic for nuetral lines

For lines that don't have a strong character and don't close a scope,
but open a math/code/raw scope - set them to LTR.

Author: IgKh

core/katvan_codemodel.cpp

@@ -148,6 +148,23 @@ static bool isDelimitedState(State state)
         || state == State::CODE_ARGUMENTS;
 }
 
+static bool isIndentingState(State state)
+{
+    return state == State::CONTENT_BLOCK
+        || state == State::CODE_BLOCK
+        || state == State::CODE_ARGUMENTS
+        || state == State::MATH_ARGUMENTS;
+}
+
+static bool isLeftLeaningState(State state)
+{
+    return state == State::CODE_BLOCK
+        || state == State::CODE_LINE
+        || state == State::MATH
+        || state == State::CONTENT_RAW
+        || state == State::CONTENT_RAW_BLOCK;
+}
+
 std::optional<int> CodeModel::findMatchingBracket(int pos) const
 {
     QTextBlock block = d_document->findBlock(pos);
@@ -184,14 +201,6 @@ std::optional<int> CodeModel::findMatchingBracket(int pos) const
     return std::nullopt;
 }
 
-static bool isIndentingState(State state)
-{
-    return state == State::CONTENT_BLOCK
-        || state == State::CODE_BLOCK
-        || state == State::CODE_ARGUMENTS
-        || state == State::MATH_ARGUMENTS;
-}
-
 std::optional<StateSpan> CodeModel::spanAtPosition(QTextBlock block, int globalPos) const
 {
     Q_ASSERT(d_document->findBlock(globalPos) == block);
@@ -282,6 +291,21 @@ QTextBlock CodeModel::findMatchingIndentBlock(QTextBlock block) const
     return block;
 }
 
+bool CodeModel::startsLeftLeaningSpan(QTextBlock block) const
+{
+    auto* blockData = BlockData::get<StateSpansBlockData>(block);
+    if (!blockData) {
+        return false;
+    }
+
+    for (const StateSpan& span : blockData->stateSpans()) {
+        if (span.startPos >= 0 && isLeftLeaningState(span.state)) {
+            return true;
+        }
+    }
+    return false;
+}
+
 std::tuple<State, State> CodeModel::getStatesForBracketInsertion(QTextCursor cursor) const
 {
     State prevState = State::INVALID;

core/katvan_codemodel.h

@@ -103,6 +103,11 @@ class CodeModel : public QObject
     // level. If none, returns the position's own block.
     QTextBlock findMatchingIndentBlock(QTextBlock block) const;
 
+    // For the given block, check if a "left leaning" scope starts in it. "Left
+    // leaning" means a code scope whose a-priori directionality (without knowing
+    // the content) is Left-to-Right.
+    bool startsLeftLeaningSpan(QTextBlock block) const;
+
     // Find closing bracket character that should be automatically appended
     // if _openBracket_ is inserted at the given cursor's position.
     std::optional<QChar> getMatchingCloseBracket(QTextCursor cursor, QChar openBracket) const;

core/katvan_editorlayout.cpp

@@ -503,6 +503,10 @@ Qt::LayoutDirection EditorLayout::getBlockDirection(const QTextBlock& block)
         return matchingBlock.layout()->textOption().textDirection();
     }
 
+    if (d_codeModel->startsLeftLeaningSpan(block)) {
+        return Qt::LeftToRight;
+    }
+
     QTextBlock prevBlock = block.previous();
     if (prevBlock.isValid()) {
         return prevBlock.layout()->textOption().textDirection();