Python example for QRegularExpression

- Analogous example in C++ - https://doc.qt.io/qt-6/qtwidgets-tools-regularexpression-example.html

Task-number: PYSIDE-841
Pick-to: 6.2
Change-Id: Id88824d444b2429bc2325832c4c92fb7a2d107f6
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Reviewed-by: Cristian Maureira-Fredes <cristian.maureira-fredes@qt.io>

5 files changed, 565 insertions, 0 deletions

diff --git a/examples/widgets/tools/regularexpression/doc/regularexpression-min.png b/examples/widgets/tools/regularexpression/doc/regularexpression-min.png
new file mode 100644
index 000000000..11e70f4a8
--- /dev/null
+++ b/examples/widgets/tools/regularexpression/doc/regularexpression-min.png
diff --git a/examples/widgets/tools/regularexpression/doc/regularexpression.rst b/examples/widgets/tools/regularexpression/doc/regularexpression.rst
new file mode 100644
index 000000000..b8e659904
--- /dev/null
+++ b/examples/widgets/tools/regularexpression/doc/regularexpression.rst
@@ -0,0 +1,11 @@
+QRegularExpression Example
+==========================
+
+A Python application that demonstrates the analogous example in C++
+`QRegularExpression Example
+https://doc.qt.io/qt-6/qtwidgets-tools-regularexpression-example.html`_
+
+
+.. image:: regularexpression.png
+   :width: 400
+   :alt: regularexpression example
diff --git a/examples/widgets/tools/regularexpression/regularexpression.py b/examples/widgets/tools/regularexpression/regularexpression.py
new file mode 100644
index 000000000..2741d22fa
--- /dev/null
+++ b/examples/widgets/tools/regularexpression/regularexpression.py
@@ -0,0 +1,60 @@
+#############################################################################
+##
+## Copyright (C) 2021 The Qt Company Ltd.
+## Contact: http://www.qt.io/licensing/
+##
+## This file is part of the Qt for Python examples of the Qt Toolkit.
+##
+## $QT_BEGIN_LICENSE:BSD$
+## You may use this file under the terms of the BSD license as follows:
+##
+## "Redistribution and use in source and binary forms, with or without
+## modification, are permitted provided that the following conditions are
+## met:
+##   * Redistributions of source code must retain the above copyright
+##     notice, this list of conditions and the following disclaimer.
+##   * Redistributions in binary form must reproduce the above copyright
+##     notice, this list of conditions and the following disclaimer in
+##     the documentation and/or other materials provided with the
+##     distribution.
+##   * Neither the name of The Qt Company Ltd nor the names of its
+##     contributors may be used to endorse or promote products derived
+##     from this software without specific prior written permission.
+##
+##
+## THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+## "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+## LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+## A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+## OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+## SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+## LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+## DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+## THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+## (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+## OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+##
+## $QT_END_LICENSE$
+##
+#############################################################################
+
+"""
+PySide6 port of Qt6 example qtbase/examples/widgets/tools/regularexpression
+
+More Information: https://doc.qt.io/qt-6/qtwidgets-tools-regularexpression-example.html
+"""
+import sys
+
+from regularexpressiondialog import RegularExpressionDialog
+
+from PySide6.QtWidgets import QApplication
+
+import re
+
+if __name__ == "__main__":
+    app = QApplication(sys.argv)
+
+    dialog = RegularExpressionDialog()
+    dialog.show()
+
+    sys.exit(app.exec())
diff --git a/examples/widgets/tools/regularexpression/regularexpression.pyproject b/examples/widgets/tools/regularexpression/regularexpression.pyproject
new file mode 100644
index 000000000..0896bfb7e
--- /dev/null
+++ b/examples/widgets/tools/regularexpression/regularexpression.pyproject
@@ -0,0 +1,3 @@
+{
+    "files": ["regularexpression.py", "regularexpressiondialog.py"]
+}
diff --git a/examples/widgets/tools/regularexpression/regularexpressiondialog.py b/examples/widgets/tools/regularexpression/regularexpressiondialog.py
new file mode 100644
index 000000000..9dfc194d4
--- /dev/null
+++ b/examples/widgets/tools/regularexpression/regularexpressiondialog.py
@@ -0,0 +1,491 @@
+#############################################################################
+##
+## Copyright (C) 2021 The Qt Company Ltd.
+## Contact: http://www.qt.io/licensing/
+##
+## This file is part of the Qt for Python examples of the Qt Toolkit.
+##
+## $QT_BEGIN_LICENSE:BSD$
+## You may use this file under the terms of the BSD license as follows:
+##
+## "Redistribution and use in source and binary forms, with or without
+## modification, are permitted provided that the following conditions are
+## met:
+##   * Redistributions of source code must retain the above copyright
+##     notice, this list of conditions and the following disclaimer.
+##   * Redistributions in binary form must reproduce the above copyright
+##     notice, this list of conditions and the following disclaimer in
+##     the documentation and/or other materials provided with the
+##     distribution.
+##   * Neither the name of The Qt Company Ltd nor the names of its
+##     contributors may be used to endorse or promote products derived
+##     from this software without specific prior written permission.
+##
+##
+## THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+## "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+## LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+## A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+## OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+## SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+## LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+## DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+## THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+## (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+## OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+##
+## $QT_END_LICENSE$
+##
+#############################################################################
+
+import re
+import logging
+
+from PySide6.QtCore import (QMargins, QRegularExpression, QRegularExpressionMatch,
+    QRegularExpressionMatchIterator, Qt, Slot,)
+from PySide6.QtGui import (QAction, QColor, QContextMenuEvent, QFontDatabase,
+    QGuiApplication, QIcon, QPalette,)
+from PySide6.QtWidgets import (QCheckBox, QComboBox, QDialog, QFormLayout,
+    QFrame, QGridLayout, QHBoxLayout, QLabel, QLineEdit, QPlainTextEdit,
+    QSpinBox, QTreeWidget, QTreeWidgetItem, QVBoxLayout, QWidget,)
+
+from PySide6.QtGui import QClipboard
+
+def rawStringLiteral(pattern: str) -> str:
+    pattern = 'r"' + pattern
+    pattern = pattern + '"'
+    return pattern
+
+
+def patternToCode(pattern: str) -> str:
+    pattern = pattern.replace(f"\\", f"\\\\")
+    pattern = pattern.replace(f'"', f'\\"')
+    pattern = '"' + pattern
+    pattern = pattern + '"'
+    return pattern
+
+
+def codeToPattern(code: str) -> str:
+
+    try:
+        new_code = code[0]
+    except IndexError:
+        logging.warning("code is empty")
+        return code
+
+    code_characters = [c for c in code]
+    index = 0
+    code_characters_size = len(code_characters)
+    while index < code_characters_size:
+        if code_characters[index] == '\\':
+            del code_characters[index]
+            code_characters_size -= 1
+        index +=1
+    code = "".join(code_characters)
+
+    if code.startswith('"') and code.endswith('"'):
+        code = code[1:-1]  # remove quotes
+
+    return code
+
+
+def createHorizontalSeparator() -> QFrame:
+    result = QFrame()
+    result.setFrameStyle(QFrame.HLine | QFrame.Sunken)
+    return result
+
+
+def createVerticalSeparator() -> QFrame:
+    result = QFrame()
+    result.setFrameStyle(QFrame.VLine | QFrame.Sunken)
+    return result
+
+
+class PatternLineEdit(QLineEdit):
+    def __init__(self, parent: QWidget = None):
+        super().__init__(parent)
+        self.escapeSelectionAction = QAction("Escape Selection", self)
+        self.copyToCodeAction = QAction("Copy to Code", self)
+        self.pasteFromCodeAction = QAction("Paste from Code", self)
+
+        self.setClearButtonEnabled(True)
+        self.escapeSelectionAction.triggered.connect(self.escapeSelection)
+        self.copyToCodeAction.triggered.connect(self.copyToCode)
+        self.pasteFromCodeAction.triggered.connect(self.pasteFromCode)
+
+    def escapeSelection(self):
+        selection = self.selectedText()
+        selection_start = self.selectionStart()
+        escapedSelection = QRegularExpression.escape(selection)
+        if escapedSelection != selection:
+            t = self.text()
+            t = (
+                t[: selection_start]
+                + escapedSelection
+                + t[selection_start + len(selection) :]
+            )
+            self.setText(t)
+
+    def copyToCode(self):
+        QGuiApplication.clipboard().setText(patternToCode(self.text()))
+
+    def pasteFromCode(self):
+        self.setText(codeToPattern(QGuiApplication.clipboard().text()))
+
+    def contextMenuEvent(self, event: QContextMenuEvent) -> None:
+        menu = self.createStandardContextMenu()
+        menu.setAttribute(Qt.WA_DeleteOnClose)
+        menu.addSeparator()
+        self.escapeSelectionAction.setEnabled(self.hasSelectedText())
+        menu.addAction(self.escapeSelectionAction)
+        menu.addSeparator()
+        menu.addAction(self.copyToCodeAction)
+        menu.addAction(self.pasteFromCodeAction)
+        menu.popup(event.globalPos())
+
+
+class DisplayLineEdit(QLineEdit):
+    def __init__(self, parent: QWidget = None):
+        super().__init__(parent)
+        self.setReadOnly(True)
+        self.disablePalette: QPalette = self.palette()
+        self.disablePalette.setBrush(
+            QPalette.Base,
+            self.disablePalette.brush(QPalette.Disabled, QPalette.Base),
+        )
+        self.setPalette(self.disablePalette)
+
+        self.copyAction = QAction(self)
+        self.copyAction.setText("Copy to clipboard")
+        self.copyAction.setIcon(QIcon(":/images/copy.png"))
+        self.copyAction.triggered.connect(
+            lambda: QGuiApplication.clipboard().setText(self.text())
+        )
+        self.addAction(self.copyAction, QLineEdit.TrailingPosition)
+
+
+class RegularExpressionDialog(QDialog):
+    def __init__(self, parent: QWidget = None) -> None:
+        super().__init__(parent)
+        self.setupUi()
+        self.setWindowTitle("QRegularExpression Example")
+        self.regularExpression = QRegularExpression()
+        self.patternLineEdit.textChanged.connect(self.refresh)
+        self.subjectTextEdit.textChanged.connect(self.refresh)
+        self.caseInsensitiveOptionCheckBox.toggled.connect(self.refresh)
+        self.dotMatchesEverythingOptionCheckBox.toggled.connect(self.refresh)
+        self.multilineOptionCheckBox.toggled.connect(self.refresh)
+        self.extendedPatternSyntaxOptionCheckBox.toggled.connect(self.refresh)
+        self.invertedGreedinessOptionCheckBox.toggled.connect(self.refresh)
+        self.dontCaptureOptionCheckBox.toggled.connect(self.refresh)
+        self.useUnicodePropertiesOptionCheckBox.toggled.connect(self.refresh)
+        self.offsetSpinBox.valueChanged.connect(self.refresh)
+        self.matchTypeComboBox.currentIndexChanged.connect(self.refresh)
+        self.anchoredMatchOptionCheckBox.toggled.connect(self.refresh)
+        self.dontCheckSubjectStringMatchOptionCheckBox.toggled.connect(self.refresh)
+
+        self.patternLineEdit.setText("(\\+?\\d+)-(?P<prefix>\\d+)-(?P<number>\\w+)")
+        self.subjectTextEdit.setPlainText(
+            "My office number is +43-152-0123456, my mobile is 001-41-255512"
+            " instead."
+        )
+
+        self.refresh()
+
+    def setResultUiEnabled(self, enabled: bool):
+        self.matchDetailsTreeWidget.setEnabled(enabled)
+        self.namedGroupsTreeWidget.setEnabled(enabled)
+        self.replacementTextEdit.setEnabled(enabled)
+
+    def setTextColor(self, widget: QWidget, color: QColor):
+        self.palette: QPalette = widget.palette()
+        self.palette.setColor(QPalette.Text, color)
+        widget.setPalette(self.palette)
+
+    def refresh(self):
+        self.setUpdatesEnabled(False)
+        self.pattern = self.patternLineEdit.text()
+        self.text = self.subjectTextEdit.toPlainText()
+
+        self.offsetSpinBox.setMaximum(max(0, len(self.text) - 1))
+
+        self.escapedPatternLineEdit.setText(patternToCode(self.pattern))
+        self.rawStringLiteralLineEdit.setText(rawStringLiteral(self.pattern))
+
+        self.setTextColor(
+            self.patternLineEdit,
+            self.subjectTextEdit.palette().color(QPalette.Text),
+        )
+        self.matchDetailsTreeWidget.clear()
+        self.namedGroupsTreeWidget.clear()
+        self.regexpStatusLabel.setText("")
+        self.replacementTextEdit.clear()
+
+        if not self.pattern:
+            self.setResultUiEnabled(False)
+            self.setUpdatesEnabled(True)
+            return
+
+        self.regularExpression.setPattern(self.pattern)
+
+        if not self.regularExpression.isValid():
+            self.setTextColor(self.patternLineEdit, Qt.red)
+            pattern_error_offset = self.regularExpression.patternErrorOffset()
+            error_string = self.regularExpression.errorString()
+            self.regexpStatusLabel.setText(
+                "Invalid: syntax error at position"
+                f" {pattern_error_offset}"
+                f" ({error_string})"
+            )
+            self.setResultUiEnabled(False)
+            self.setUpdatesEnabled(True)
+            return
+
+        self.setResultUiEnabled(True)
+        matchType: QRegularExpression.MatchType = QRegularExpression.MatchType(
+            self.matchTypeComboBox.currentData()
+        )
+        patternOptions = QRegularExpression.NoPatternOption
+        matchOptions = QRegularExpression.NoMatchOption
+
+        if self.anchoredMatchOptionCheckBox.isChecked():
+            matchOptions |= QRegularExpression.AnchorAtOffsetMatchOption
+        if self.dontCheckSubjectStringMatchOptionCheckBox.isChecked():
+            matchOptions |= QRegularExpression.DontCheckSubjectStringMatchOption
+
+        if self.caseInsensitiveOptionCheckBox.isChecked():
+            patternOptions |= QRegularExpression.CaseInsensitiveOption
+        if self.dotMatchesEverythingOptionCheckBox.isChecked():
+            patternOptions |= QRegularExpression.DotMatchesEverythingOption
+        if self.multilineOptionCheckBox.isChecked():
+            patternOptions |= QRegularExpression.MultilineOption
+        if self.extendedPatternSyntaxOptionCheckBox.isChecked():
+            patternOptions |= QRegularExpression.ExtendedPatternSyntaxOption
+        if self.invertedGreedinessOptionCheckBox.isChecked():
+            patternOptions |= QRegularExpression.InvertedGreedinessOption
+        if self.dontCaptureOptionCheckBox.isChecked():
+            patternOptions |= QRegularExpression.DontCaptureOption
+        if self.useUnicodePropertiesOptionCheckBox.isChecked():
+            patternOptions |= QRegularExpression.UseUnicodePropertiesOption
+
+        self.regularExpression.setPatternOptions(patternOptions)
+
+        capturingGroupsCount = self.regularExpression.captureCount() + 1
+
+        offset = self.offsetSpinBox.value()
+        iterator: QRegularExpressionMatchIterator = self.regularExpression.globalMatch(
+            self.text, offset, matchType, matchOptions
+        )
+        i = 0
+
+        while iterator.hasNext():
+            match: QRegularExpressionMatch = iterator.next()
+            matchDetailTopItem = QTreeWidgetItem(self.matchDetailsTreeWidget)
+            matchDetailTopItem.setText(0, str(i))
+
+            for captureGroupIndex in range(capturingGroupsCount):
+                matchDetailItem = QTreeWidgetItem(matchDetailTopItem)
+                matchDetailItem.setText(1, str(captureGroupIndex))
+                matchDetailItem.setText(2, match.captured(captureGroupIndex))
+
+            i = i + 1
+
+        self.matchDetailsTreeWidget.expandAll()
+
+        self.regexpStatusLabel.setText("Valid")
+
+        namedCaptureGroups = self.regularExpression.namedCaptureGroups()
+        for i in range(len(namedCaptureGroups)):
+            currentNamedCaptureGroup = namedCaptureGroups[i]
+            namedGroupItem = QTreeWidgetItem(self.namedGroupsTreeWidget)
+            namedGroupItem.setText(0, str(i))
+            namedGroupItem.setText(
+                1,
+                "<no name>"
+                if not currentNamedCaptureGroup
+                else currentNamedCaptureGroup,
+            )
+
+        self.updateReplacement()
+        self.setUpdatesEnabled(True)
+
+    @Slot()
+    def updateReplacement(self):
+        self.replacementTextEdit.clear()
+        replacement = self.replacementLineEdit.text()
+        if not self.regularExpression.isValid() or not replacement:
+            return
+
+        current_text = self.subjectTextEdit.toPlainText()
+        regular_expression_pattern = self.regularExpression.pattern()
+
+        new_text = re.sub(regular_expression_pattern, replacement, current_text)
+        self.replacementTextEdit.setPlainText(new_text)
+
+    def setupUi(self):
+        self.mainLayout = QVBoxLayout(self)
+        self.mainLayout.addWidget(self.setupTextUi())
+        self.mainLayout.addWidget(createHorizontalSeparator())
+
+        self.horizontalLayout = QHBoxLayout()
+        self.mainLayout.addLayout(self.horizontalLayout)
+        self.horizontalLayout.addWidget(self.setupOptionsUi())
+        self.horizontalLayout.addWidget(createVerticalSeparator())
+        self.horizontalLayout.addWidget(self.setupInfoUi())
+
+        self._font = QFontDatabase.systemFont(QFontDatabase.FixedFont)
+        self.patternLineEdit.setFont(self._font)
+        self.rawStringLiteralLineEdit.setFont(self._font)
+        self.escapedPatternLineEdit.setFont(self._font)
+        self.replacementLineEdit.setFont(self._font)
+        self.subjectTextEdit.setFont(self._font)
+        self.replacementTextEdit.setFont(self._font)
+
+    def setupOptionsUi(self):
+        container = QWidget()
+
+        form_layout = QFormLayout(container)
+        form_layout.setFieldGrowthPolicy(QFormLayout.AllNonFixedFieldsGrow)
+        form_layout.setContentsMargins(QMargins())
+
+        form_layout.addRow(QLabel("<h3>Options</h3>"))
+
+        self.caseInsensitiveOptionCheckBox = QCheckBox("Case insensitive (/i)")
+        self.dotMatchesEverythingOptionCheckBox = QCheckBox("Dot matches everything (/s)")
+        self.multilineOptionCheckBox = QCheckBox("Multiline (/m)")
+        self.extendedPatternSyntaxOptionCheckBox = QCheckBox("Extended pattern (/x)")
+        self.invertedGreedinessOptionCheckBox = QCheckBox("Inverted greediness")
+        self.dontCaptureOptionCheckBox = QCheckBox("Don't capture")
+        self.useUnicodePropertiesOptionCheckBox = QCheckBox("Use unicode properties (/u)")
+
+        self.patternOptionsCheckBoxLayout = QGridLayout()
+        gridRow = 0
+
+        self.patternOptionsCheckBoxLayout.addWidget(self.caseInsensitiveOptionCheckBox, gridRow, \
+        1)
+        self.patternOptionsCheckBoxLayout.addWidget(self.dotMatchesEverythingOptionCheckBox, gridRow\
+        ,2)
+        gridRow = gridRow + 1
+        self.patternOptionsCheckBoxLayout.addWidget(self.multilineOptionCheckBox, gridRow, \
+        1)
+        self.patternOptionsCheckBoxLayout.addWidget(self.extendedPatternSyntaxOptionCheckBox, gridRow \
+        , 2)
+        gridRow = gridRow + 1
+        self.patternOptionsCheckBoxLayout.addWidget(self.invertedGreedinessOptionCheckBox, gridRow,\
+        1)
+        self.patternOptionsCheckBoxLayout.addWidget(self.dontCaptureOptionCheckBox, gridRow,\
+        2)
+        gridRow = gridRow + 1
+        self.patternOptionsCheckBoxLayout.addWidget(self.useUnicodePropertiesOptionCheckBox, gridRow,\
+        1)
+
+        form_layout.addRow("Pattern options:", self.patternOptionsCheckBoxLayout)
+
+        self.offsetSpinBox = QSpinBox()
+        form_layout.addRow("Match &offset:", self.offsetSpinBox)
+
+        self.matchTypeComboBox = QComboBox()
+        self.matchTypeComboBox.addItem("Normal", QRegularExpression.NormalMatch)
+        self.matchTypeComboBox.addItem(
+            "Partial prefer complete",
+            QRegularExpression.PartialPreferCompleteMatch,
+        )
+        self.matchTypeComboBox.addItem(
+            "Partial prefer first", QRegularExpression.PartialPreferFirstMatch
+        )
+        self.matchTypeComboBox.addItem("No match", QRegularExpression.NoMatch)
+        form_layout.addRow("Match &type:", self.matchTypeComboBox)
+
+        self.dontCheckSubjectStringMatchOptionCheckBox = QCheckBox(
+            "Don't check subject string"
+        )
+        self.anchoredMatchOptionCheckBox = QCheckBox("Anchored match")
+
+        self.matchOptionsCheckBoxLayout = QGridLayout()
+        self.matchOptionsCheckBoxLayout.addWidget(
+            self.dontCheckSubjectStringMatchOptionCheckBox, 0, 0
+        )
+        self.matchOptionsCheckBoxLayout.addWidget(
+            self.anchoredMatchOptionCheckBox, 0, 1
+        )
+        form_layout.addRow("Match options:", self.matchOptionsCheckBoxLayout)
+
+        return container
+
+    def setupInfoUi(self):
+        container = QWidget()
+
+        form_layout = QFormLayout(container)
+        form_layout.setFieldGrowthPolicy(QFormLayout.AllNonFixedFieldsGrow)
+        form_layout.setContentsMargins(QMargins())
+
+        self.matchInfoLabel = QLabel("<h3>Match information</h3>")
+        form_layout.addRow(self.matchInfoLabel)
+
+        self.matchDetailsTreeWidget = QTreeWidget()
+
+        self.matchDetailsTreeWidget.setHeaderLabels(
+            ["Match index", "Group index", "Captured string"]
+        )
+        self.matchDetailsTreeWidget.setSizeAdjustPolicy(QTreeWidget.AdjustToContents)
+        form_layout.addRow("Match details:", self.matchDetailsTreeWidget)
+
+        form_layout.addRow(createHorizontalSeparator())
+
+        self.regexpInfoLabel = QLabel("<h3>Regular expression information</h3>")
+        form_layout.addRow(self.regexpInfoLabel)
+
+        self.regexpStatusLabel = QLabel("Valid")
+        self.regexpStatusLabel.setWordWrap(True)
+        form_layout.addRow("Pattern status:", self.regexpStatusLabel)
+
+        self.namedGroupsTreeWidget = QTreeWidget()
+        self.namedGroupsTreeWidget.setHeaderLabels(["Index", "Named group"])
+        self.namedGroupsTreeWidget.setSizeAdjustPolicy(QTreeWidget.AdjustToContents)
+        self.namedGroupsTreeWidget.setRootIsDecorated(False)
+        form_layout.addRow("Named groups:", self.namedGroupsTreeWidget)
+
+        return container
+
+    def setupTextUi(self):
+        container = QWidget()
+        form_layout = QFormLayout(container)
+        form_layout.setFieldGrowthPolicy(QFormLayout.AllNonFixedFieldsGrow)
+        form_layout.setContentsMargins(QMargins())
+
+        self.regexpAndSubjectLabel = QLabel(
+            "<h3>Regular expression and text input</h3>"
+        )
+        form_layout.addRow(self.regexpAndSubjectLabel)
+
+        self.patternLineEdit = PatternLineEdit()
+        self.patternLineEdit.setClearButtonEnabled(True)
+        form_layout.addRow("&Pattern:", self.patternLineEdit)
+
+        self.rawStringLiteralLineEdit = DisplayLineEdit()
+        form_layout.addRow("&Raw string literal:", self.rawStringLiteralLineEdit)
+
+        self.escapedPatternLineEdit = DisplayLineEdit()
+        form_layout.addRow("&Escaped pattern:", self.escapedPatternLineEdit)
+
+        self.subjectTextEdit = QPlainTextEdit()
+        form_layout.addRow("&Subject text:", self.subjectTextEdit)
+
+        form_layout.addRow(createHorizontalSeparator())
+
+        self.replaceLabel = QLabel("<h3>Replacement")
+        form_layout.addRow(self.replaceLabel)
+
+        self.replacementLineEdit = QLineEdit()
+        self.replacementLineEdit.setClearButtonEnabled(True)
+        self.replacementLineEdit.textChanged.connect(self.updateReplacement)
+        form_layout.addRow("&Replace by:", self.replacementLineEdit)
+        self.replacementLineEdit.setToolTip(
+            "Use \\1, \\2... as placeholders for the captured groups."
+        )
+
+        self.replacementTextEdit = QPlainTextEdit()
+        self.replacementTextEdit.setReadOnly(True)
+        form_layout.addRow("Result:", self.replacementTextEdit)
+
+        return container