Support more than one line in the Python Console & Refactor #665

Tucchhaa · 2026-01-27T06:08:59Z

This PR changes to the layout of Python Console in pilot.

How it looked before:

How it looks now:

Multiline commands support:

Tucchhaa · 2026-01-27T06:19:44Z

cpp/modmesh/pilot/RPythonConsoleDockWidget.cpp

+    connect(
+        m_history_edit->document(),
+        &QTextDocument::contentsChanged,
+        this,
+        [this]()
+        {
+            const int newHeight = calcHeightToFitContents(m_history_edit);
+            m_history_edit->setMinimumHeight(newHeight);
+        });


set minHeight to history editor so that it would fill all free space in scrollArea if there's some

Tucchhaa · 2026-01-27T06:20:34Z

cpp/modmesh/pilot/RPythonConsoleDockWidget.cpp

+    connect(
+        m_command_edit->document(),
+        &QTextDocument::contentsChanged,
+        this,
+        [this, commandEditMinHeight]()
+        {
+            const int newHeight = std::max(calcHeightToFitContents(m_command_edit), commandEditMinHeight);
+            m_command_edit->setFixedHeight(newHeight);
+        });


set fixedHeight to commandEdit so that it is big enough to contain all the text, but doesn't stretch if scrollArea has free space

Tucchhaa · 2026-01-27T06:21:51Z

cpp/modmesh/pilot/RPythonConsoleDockWidget.cpp

+    std::string const command = m_command_edit->toPlainText().trimmed().toStdString();
+
+    if (command.length() == 0)
+    {
+        return;
+    }


added trimmed(), so that user wouldn't execute empty command

Tucchhaa · 2026-01-27T06:22:30Z

cpp/modmesh/pilot/RPythonConsoleDockWidget.cpp

-        printCommandStdout(m_python_redirect.stdout_string());
-        printCommandStderr(m_python_redirect.stderr_string());


printCommandStderr and printCommandStdout were duplicates of writeToHistory so I removed them

Personally, I think we should keep them into two functions or a single function with different arguments to distinguish stdout and stderr, which is helpful when we give different color for them.

I don't know. Sending the log through a unified API is good. But it's bad to combine stdout and stderr.

It's hard to decide, so we should not change it right now. Please keep the old code.

Ok, I can bring these functions back. But how about I mark output of stderr with red color?

So I've tried to mark stderr with red color and here's what I got:

I have added stdout: and stderr: strings to distinguish outputs of printCommandStdout and printCommandStderr.

As you can see when an exception occurs both stdout and stderr have something to output.

Should we mark both of them with red color or only stderr? Or should we just postpone this and keep the old behavior?

Ok, I think I will keep the old behavior for now

Tucchhaa · 2026-01-27T06:24:08Z

cpp/modmesh/pilot/RPythonConsoleDockWidget.cpp

    QTextCursor cursor = m_history_edit->textCursor();
    cursor.movePosition(QTextCursor::End);
    m_history_edit->setTextCursor(cursor);
    m_history_edit->insertPlainText(QString::fromStdString(data));
-    cursor.movePosition(QTextCursor::End);
-    m_history_edit->setTextCursor(cursor);


Looks like we just need to set cursor before we write to the editor since it's read-only editor

Tucchhaa · 2026-01-27T06:26:17Z

cpp/modmesh/pilot/RPythonConsoleDockWidget.cpp

+    setCommand(QString::fromStdString(command_to_show));
 }

-void RPythonConsoleDockWidget::navigateCommand(int offset)


this function contained a bug, when not yet executed command couldn't be restored after navigating to past commands and back to the not yet executed command. So I have fixed the bug and simplified the function.

Good catch. I didn't notice it behaved incorrectly that way.

Tucchhaa · 2026-01-27T06:26:51Z

cpp/modmesh/pilot/RPythonConsoleDockWidget.cpp

+    const auto formatted_command = std::format("[{}] {}\n\n", m_last_command_serial, command);
+    writeToHistory(formatted_command);


this is an equivalent replacement of printCommandHistory() function

Tucchhaa · 2026-01-27T06:27:39Z

cpp/modmesh/pilot/RPythonConsoleDockWidget.cpp

+    const bool is_first_line_focused = cursor.blockNumber() == 0;
+    const bool is_last_line_focused = cursor.blockNumber() == document()->blockCount() - 1;


need this so that navigation between lines of a past command is possible

tigercosmos

It's recommended to write something in the PR description. Attaching some screenshots is also helpful as it's a GUI change.

tigercosmos · 2026-01-29T14:52:37Z

cpp/modmesh/pilot/RPythonConsoleDockWidget.cpp

-        execute();
+        if (event->modifiers() & Qt::ShiftModifier)
+        {
+            this->insertPlainText("\n");


Question: what happens on Windows?

Good question. @Tucchhaa , if you don't have time/environment to test for the behaviors on Windows, make a guess.

I don't have Windows environment. But I'm pretty sure it behaves the same as on MacOS, since Qt is not OS specific.

I asked chatgpt about it and told the same thing.

Good to know that the code is based a guess. Line ending on Windows, Mac, and Linux are \r\n (CR LF), \r (CR), and \n (LF). That is a concern. But I agree that if \n works on Mac. We can have the fingers cross before some nice people point out issues on Windows.

Let's avoid using AI tools as a reference. They do not have credibility. (Using them and studying yourself is fine.)

tigercosmos · 2026-01-29T14:55:24Z

cpp/modmesh/pilot/RPythonConsoleDockWidget.cpp

+        }
    }
-    else if (Qt::Key_Up == event->key())
+    else if (Qt::Key_Up == event->key() && is_first_line_focused)


Could you describe what is the behaviour difference before and after and is the difference expected?

A quick description suffices.

This code is needed to make navigation in multiline command more convenient in case when there are previous commands.

Suppose we don't have is_first_line_focused, here's what will happen in a simple user case:

User executes any command, e.g.: a = 9

Then user writes this multiline command, but he doesn't executes it yet:

b = 10 c = 11 print(a + b + c)

Since user just typed it, the focus is on the last line. Then user realizes that the value of c is incorrect and he wants to change it to 12

So user presses arrow up to focus the second line c = 11, but instead of moving focus up, navigate function will be called which will change the value of command editor to previous command, which is a = 9

With is_first_line_focused this behavior is prevented. And so pilot's command editor behaves just like any other terminal. The similar reason why we need is_last_line_focused

Thank you. Very clear elaboration.

tigercosmos · 2026-01-29T15:00:29Z

cpp/modmesh/pilot/RPythonConsoleDockWidget.cpp

-        printCommandStdout(m_python_redirect.stdout_string());
-        printCommandStderr(m_python_redirect.stderr_string());


Personally, I think we should keep them into two functions or a single function with different arguments to distinguish stdout and stderr, which is helpful when we give different color for them.

yungyuc

Nice work. Some comments:

Add summary in the opening PR comment block. (Just edit it.) Include some screenshots of the new UI. It would be good to also include screenshots of the old UI to make a comparison.
Keep the old printCommandStdout and printCommandStderr before we have a better idea for how to handle the text logging.

After the discussion converges and the code can be finalized, commits should be squashed because the overall change is straight-forward. Formatting should not use distinct commits.

Refactoring may use distinct commits, although for this PR, it does not matter. Do what you like.

But before the PR is close to merging, feel free to stack commits.

yungyuc · 2026-01-30T13:07:04Z

cpp/modmesh/pilot/RPythonConsoleDockWidget.cpp

-        execute();
+        if (event->modifiers() & Qt::ShiftModifier)
+        {
+            this->insertPlainText("\n");


Good question. @Tucchhaa , if you don't have time/environment to test for the behaviors on Windows, make a guess.

yungyuc · 2026-01-30T13:08:21Z

cpp/modmesh/pilot/RPythonConsoleDockWidget.cpp

+        }
    }
-    else if (Qt::Key_Up == event->key())
+    else if (Qt::Key_Up == event->key() && is_first_line_focused)


A quick description suffices.

yungyuc · 2026-01-30T13:09:32Z

cpp/modmesh/pilot/RPythonConsoleDockWidget.cpp

 {
-    setWidget(new QWidget);
-    widget()->setLayout(new QVBoxLayout);
+    m_scroll_area->setWidgetResizable(true);


I like the use of a scroll area. @Tucchhaa do you think it stands a chance to be extended to be a rich-text editor (in the future)?

Depends on what you consider a rich-text editor :)

For me, I think we would need to add the following features:

Syntax highlighting for command editor and history editor. it can be implemented using QSyntaxHighlighter and it seems not too difficult to implement.

Suggestion popup-list in command editor that will be shown when user types a variable or function name. This can be challenging to implement but still possible in my opinion.

With these features pilot's console will be very similar to browser's console and pretty convenient to use.

However we can go further and implement jupyter notebook-like editor. Since QTextEdit supports HTML (tables, hyperlinks even images can be inserted into the editor), it seems that this feature is feasible

Making it like a terminal (emulator) or jupyter notebook like editor will be fantastic. We can talk more about it.

Maybe I could create an issue with the action plan of step-by-step development of rich-text editor?

Like :
Step 1: implement syntax highlighting in command editor and history editor
Step 2: implement suggestion popup-list
Step 3: Research possibility of jupyter-notebook like implementation.

And each step with some implementation details (like usage of QSyntaxHighlighter)

What do you think?

Maybe I could create an issue with the action plan of step-by-step development of rich-text editor?

Like :
Step 1: implement syntax highlighting in command editor and history editor
Step 2: implement suggestion popup-list
Step 3: Research possibility of jupyter-notebook like implementation.

And each step with some implementation details (like usage of QSyntaxHighlighter)

What do you think?

It will be fantastic. Please go ahead.

A discussion topic (in https://github.com/solvcon/modmesh/discussions) may be more suitable than an issue at the moment. It's up to you.

Ok, I will do that in a week or so

yungyuc · 2026-01-30T13:12:38Z

cpp/modmesh/pilot/RPythonConsoleDockWidget.cpp

-        printCommandStdout(m_python_redirect.stdout_string());
-        printCommandStderr(m_python_redirect.stderr_string());


I don't know. Sending the log through a unified API is good. But it's bad to combine stdout and stderr.

It's hard to decide, so we should not change it right now. Please keep the old code.

yungyuc · 2026-01-30T13:15:11Z

cpp/modmesh/pilot/RPythonConsoleDockWidget.cpp

+    setCommand(QString::fromStdString(command_to_show));
 }

-void RPythonConsoleDockWidget::navigateCommand(int offset)


Good catch. I didn't notice it behaved incorrectly that way.

yungyuc

Leave a global comment to request for a next review. No need to press the ready for review button. We do not pay attention to it.

yungyuc · 2026-02-01T01:03:53Z

cpp/modmesh/pilot/RPythonConsoleDockWidget.cpp

+        }
    }
-    else if (Qt::Key_Up == event->key())
+    else if (Qt::Key_Up == event->key() && is_first_line_focused)


Thank you. Very clear elaboration.

yungyuc · 2026-02-01T01:04:48Z

cpp/modmesh/pilot/RPythonConsoleDockWidget.cpp

 {
-    setWidget(new QWidget);
-    widget()->setLayout(new QVBoxLayout);
+    m_scroll_area->setWidgetResizable(true);


Making it like a terminal (emulator) or jupyter notebook like editor will be fantastic. We can talk more about it.

yungyuc · 2026-02-01T01:09:53Z

cpp/modmesh/pilot/RPythonConsoleDockWidget.cpp

-        execute();
+        if (event->modifiers() & Qt::ShiftModifier)
+        {
+            this->insertPlainText("\n");


Good to know that the code is based a guess. Line ending on Windows, Mac, and Linux are \r\n (CR LF), \r (CR), and \n (LF). That is a concern. But I agree that if \n works on Mac. We can have the fingers cross before some nice people point out issues on Windows.

Let's avoid using AI tools as a reference. They do not have credibility. (Using them and studying yourself is fine.)

Tucchhaa · 2026-02-01T02:34:20Z

@yungyuc @tigercosmos I have brought back printCommandStdout and printCommandStderr. Can you review again, please?

Should I squash and force push commits to this PR? Or will the PR be squashed and merged?

yungyuc

LGTM

@yungyuc @tigercosmos I have brought back printCommandStdout and printCommandStderr. Can you review again, please?

Thank you. This is a good summary. Requesting for a next review with a good summary like this benefits both the contributor and the reviewers. It helps the contributor to pro-actively pre-review before requesting, and the reviewers to know what to read.

All PRs should be carried out in this way. I did not document it in this repository but I should.

Should I squash and force push commits to this PR? Or will the PR be squashed and merged?

Yes, please squash and make a new commit or commits, because it's close to be merged. For a small PR like this (around 100 LoC), using one commit suffices, but might not hurt to use 2 or 3.

Do notify with a global comment after it's squashed and ready for the next review.

yungyuc · 2026-02-02T09:46:51Z

@Tucchhaa I merged the CI-fixing PR #670 . Please rebase to pick it up.

Tucchhaa · 2026-02-02T10:27:50Z

@Tucchhaa I merged the CI-fixing PR #670 . Please rebase to pick it up.

@yungyuc thank you, I have rebased my PR

yungyuc

I have rebased my PR

CI is clean. Good to merge.

yungyuc · 2026-02-02T12:18:45Z

cpp/modmesh/pilot/RPythonConsoleDockWidget.cpp

 {
-    setWidget(new QWidget);
-    widget()->setLayout(new QVBoxLayout);
+    m_scroll_area->setWidgetResizable(true);


Maybe I could create an issue with the action plan of step-by-step development of rich-text editor?

Like :
Step 1: implement syntax highlighting in command editor and history editor
Step 2: implement suggestion popup-list
Step 3: Research possibility of jupyter-notebook like implementation.

And each step with some implementation details (like usage of QSyntaxHighlighter)

What do you think?

It will be fantastic. Please go ahead.

A discussion topic (in https://github.com/solvcon/modmesh/discussions) may be more suitable than an issue at the moment. It's up to you.

yungyuc · 2026-02-02T12:22:20Z

@Tucchhaa I forgot to ask you to update the commit with a summary of the change, but it's already merged. Please add good summary to each of your future commits. Do not use conventional/semantic commit messages, which are not suitable for the computing code.

Tucchhaa commented Jan 27, 2026

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Tucchhaa marked this pull request as ready for review January 27, 2026 06:42

Tucchhaa marked this pull request as draft January 27, 2026 06:43

Tucchhaa mentioned this pull request Jan 27, 2026

Support more than one line in the python input box #173

Open

Tucchhaa marked this pull request as ready for review January 28, 2026 03:12

tigercosmos reviewed Jan 29, 2026

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yungyuc requested changes Jan 30, 2026

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yungyuc assigned Tucchhaa Jan 30, 2026

yungyuc added the pilot GUI and visualization label Jan 30, 2026

Tucchhaa requested a review from tigercosmos January 31, 2026 05:55

yungyuc requested changes Feb 1, 2026

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Tucchhaa requested a review from yungyuc February 1, 2026 02:34

yungyuc approved these changes Feb 1, 2026

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Tucchhaa force-pushed the issue_173 branch 2 times, most recently from e91666d to 46ae19b Compare February 2, 2026 03:08

Support more than one line in the Python Console

b3d0cd3

Tucchhaa force-pushed the issue_173 branch from 46ae19b to b3d0cd3 Compare February 2, 2026 10:27

yungyuc requested changes Feb 2, 2026

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yungyuc merged commit c002d20 into solvcon:master Feb 2, 2026
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yungyuc linked an issue Feb 2, 2026 that may be closed by this pull request

Support more than one line in the python input box #173

Open

		printCommandStdout(m_python_redirect.stdout_string());
		printCommandStderr(m_python_redirect.stderr_string());

		const auto formatted_command = std::format("[{}] {}\n\n", m_last_command_serial, command);
		writeToHistory(formatted_command);

		const bool is_first_line_focused = cursor.blockNumber() == 0;
		const bool is_last_line_focused = cursor.blockNumber() == document()->blockCount() - 1;

Support more than one line in the Python Console & Refactor #665

Support more than one line in the Python Console & Refactor #665

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Tucchhaa commented Jan 27, 2026 •

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