# CodeEditor based on QT example, Python syntax highlighter found on Python site import enum import typing from ast import parse from PyQt5.QtGui import QTextCharFormat from ..Qt import QtGui, QtCore, QtWidgets def _make_textformats(color, style=''): """Return a QTextCharFormat with the given attributes. """ _color = QtGui.QColor() _color.setNamedColor(color) _format = QtGui.QTextCharFormat() _format.setForeground(_color) if 'bold' in style: _format.setFontWeight(QtGui.QFont.Weight.Bold) if 'italic' in style: _format.setFontItalic(True) return _format # Syntax styles that can be shared by all languages class CodeStyle(enum.Enum): KEYWORD = _make_textformats('blue') OPERATOR = _make_textformats('black') BRACE = _make_textformats('black') CLASS_DEFINE = _make_textformats('black', 'bold') STRING = _make_textformats('darkGreen') COMMENT = _make_textformats('gray', 'italic') SELF = _make_textformats('brown', 'italic') PROPERTY = _make_textformats('brown') NUMBER = _make_textformats('darkRed') class PythonHighlighter(QtGui.QSyntaxHighlighter): """ Syntax highlighter for the Python language. """ # Python keywords keywords = [ 'and', 'assert', 'break', 'class', 'continue', 'def', 'del', 'elif', 'else', 'except', 'exec', 'finally', 'for', 'from', 'global', 'if', 'import', 'in', 'is', 'lambda', 'not', 'or', 'pass', 'print', 'raise', 'return', 'try', 'while', 'yield', 'None', 'True', 'False', 'object' ] def __init__(self, document): super().__init__(document) # Multi-line strings (expression, flag, style) # FIXME: The triple-quotes in these two lines will mess up the # syntax highlighting from this point onward self.tri_single = (QtCore.QRegularExpression("r'{3}"), 1, CodeStyle.STRING.value) self.tri_double = (QtCore.QRegularExpression('r?"{3}'), 2, CodeStyle.STRING.value) rules = [] # Keyword, operator, and brace rules rules += [(rf'\b{w}\b', 0, CodeStyle.KEYWORD.value) for w in PythonHighlighter.keywords] # Other rules rules += [ # 'self' (r'\bself\b', 0, CodeStyle.SELF.value), # 'def' followed by an identifier (r'\bdef\b\s*(\w+)', 1, CodeStyle.CLASS_DEFINE.value), # 'class' followed by an identifier (r'\bclass\b\s*(\w+)', 1, CodeStyle.CLASS_DEFINE.value), # decorator @ followed by a word (r'\s*@(\w+)\s*', 0, CodeStyle.PROPERTY.value), # Numeric literals (r'\b[+-]?\d+[lL]?\b', 0, CodeStyle.NUMBER.value), (r'\b[+-]?0[xX][\dA-Fa-f]+[lL]?\b', 0, CodeStyle.NUMBER.value), (r'\b[+-]?\d+(?:\.\d+)?(?:[eE][+-]?\d+)?\b', 0, CodeStyle.NUMBER.value), # Double-quoted string, possibly containing escape sequences (r'[rf]?"[^"\\]*(\\.[^"\\]*)*"', 0, CodeStyle.STRING.value), # Single-quoted string, possibly containing escape sequences (r"[rf]?'[^'\\]*(\\.[^'\\]*)*'", 0, CodeStyle.STRING.value), # From '#' until a newline (r'#[^\n]*', 0, CodeStyle.COMMENT.value), ] # Build a QRegExp for each pattern self.rules = [(QtCore.QRegularExpression(pat), index, fmt) for (pat, index, fmt) in rules] def highlightBlock(self, text): """ Apply syntax highlighting to the given block of text. """ # Do other syntax formatting for expression, nth, rule in self.rules: index = expression.globalMatch(text) while index.hasNext(): match = index.next() self.setFormat(match.capturedStart(nth), match.capturedLength(nth), rule) self.setCurrentBlockState(0) # Do multi-line strings in_multiline = self.match_multiline(text, *self.tri_single) if not in_multiline: in_multiline = self.match_multiline(text, *self.tri_double) def match_multiline(self, text: str, delimiter: QtCore.QRegularExpression, in_state: int, style: QtGui.QTextCharFormat): """ Highlighting of multi-line strings. ``delimiter`` should be a ``QRegExp`` for triple-single-quotes or triple-double-quotes, and ``in_state`` should be a unique integer to represent the corresponding state changes when inside those strings. Returns True if we're still inside a multi-line string when this function is finished. """ # If inside triple-single quotes, start at 0 # TODO return False # if self.previousBlockState() == in_state: # start = 0 # add = 0 # # Otherwise, look for the delimiter on this line # else: # start = delimiter.match(text). # # Move past this match # add = delimiter.matchedLength() # # # As long as there's a delimiter match on this line... # while start >= 0: # # Look for the ending delimiter # end = delimiter.indexIn(text, start + add) # # Ending delimiter on this line? # if end >= add: # length = end - start + add + delimiter.matchedLength() # self.setCurrentBlockState(0) # # No; multi-line string # else: # self.setCurrentBlockState(in_state) # try: # length = text.length() - start + add # except AttributeError: # length = len(text) - start + add # # Apply formatting # self.setFormat(start, length, style) # # Look for the next match # start = delimiter.indexIn(text, start + length) # # # Return True if still inside a multi-line string, False otherwise # if self.currentBlockState() == in_state: # return True # else: # return False class LineNumbers(QtWidgets.QWidget): def __init__(self, editor): super().__init__(editor) self.editor = editor def sizeHint(self): return QtCore.QSize(self.editor.width_linenumber, 0) def paintEvent(self, event): self.editor.paintevent_linenumber(event) class CodeEditor(QtWidgets.QPlainTextEdit): # more or less a direct translation of the Qt example def __init__(self, parent): super().__init__(parent) self.current_linenumber = LineNumbers(self) self.blockCountChanged.connect(self.update_width_linenumber) self.updateRequest.connect(self.update_current_area) self.cursorPositionChanged.connect(self.highlight_current_line) self.update_width_linenumber(0) self.highlight = PythonHighlighter(self.document()) def keyPressEvent(self, evt): if evt.key() == QtCore.Qt.Key.Key_Tab: # use spaces instead of tab self.insertPlainText(' '*4) elif evt.key() == QtCore.Qt.Key.Key_Insert: self.setOverwriteMode(not self.overwriteMode()) else: super().keyPressEvent(evt) def width_linenumber(self): digits = 1 count = max(1, self.blockCount()) while count >= 10: count /= 10 digits += 1 space = 6 + self.fontMetrics().horizontalAdvance('9') * digits return space def update_width_linenumber(self, _): self.setViewportMargins(self.width_linenumber(), 0, 0, 0) def update_current_area(self, rect, dy): if dy: self.current_linenumber.scroll(0, dy) else: self.current_linenumber.update(0, rect.y(), self.current_linenumber.width(), rect.height()) if rect.contains(self.viewport().rect()): self.update_width_linenumber(0) def resizeEvent(self, evt): super().resizeEvent(evt) cr = self.contentsRect() self.current_linenumber.setGeometry(QtCore.QRect(cr.left(), cr.top(), self.width_linenumber(), cr.height())) def paintevent_linenumber(self, evt): painter = QtGui.QPainter(self.current_linenumber) painter.fillRect(evt.rect(), QtCore.Qt.GlobalColor.lightGray) block = self.firstVisibleBlock() block_number = block.blockNumber() top = self.blockBoundingGeometry(block).translated(self.contentOffset()).top() bottom = top + self.blockBoundingRect(block).height() # Just to make sure I use the right font height = self.fontMetrics().height() while block.isValid() and (top <= evt.rect().bottom()): if block.isVisible() and (bottom >= evt.rect().top()): number = str(block_number + 1) painter.setPen(QtCore.Qt.GlobalColor.black) painter.drawText(0, int(top), self.current_linenumber.width() - 3, height, QtCore.Qt.AlignmentFlag.AlignRight, number) block = block.next() top = bottom bottom = top + self.blockBoundingRect(block).height() block_number += 1 def highlight_current_line(self): extra_selections = [] if not self.isReadOnly(): selection = QtWidgets.QTextEdit.ExtraSelection() line_color = QtGui.QColor(QtCore.Qt.GlobalColor.yellow).lighter(180) selection.format.setBackground(line_color) selection.format.setProperty(QtGui.QTextFormat.Property.FullWidthSelection, True) selection.cursor = self.textCursor() selection.cursor.clearSelection() extra_selections.append(selection) self.setExtraSelections(extra_selections) class EditorWidget(QtWidgets.QWidget): def __init__(self, parent=None): super().__init__(parent=parent) layout = QtWidgets.QVBoxLayout() layout.setContentsMargins(0, 0, 0, 0) self.editor = CodeEditor(self) layout.addWidget(self.editor) self.error_label = QtWidgets.QLabel(self) font = QtGui.QFont() font.setBold(True) font.setWeight(75) self.error_label.setFont(font) self.error_label.setVisible(False) layout.addWidget(self.error_label) self.setLayout(layout) for attr in ['appendPlainText', 'toPlainText', 'insertPlainText', 'setPlainText']: setattr(self, attr, getattr(self.editor, attr)) self.editor.textChanged.connect(self._check_syntax) def _check_syntax(self) -> (int, tuple[typing.Any]): is_valid = True # Compile into an AST and check for syntax errors. try: _ = parse(self.toPlainText(), filename='') except SyntaxError as e: self.error_label.setText(f'Syntax error in line {e.lineno}: {e.args[0]}') is_valid = False except Exception as e: self.error_label.setText(f'Unexpected error: {e.args[0]}') is_valid = False self.error_label.setVisible(not is_valid)