from PyQt5.QtCore import QRegExp
from PyQt5.QtGui import QColor, QTextCharFormat, QFont, QSyntaxHighlighter
# Syntax styles that can be shared by all languages
STYLES = {
'keyword': format('blue'),
'operator': format('red'),
'brace': format('darkGray'),
'defclass': format('black', 'bold'),
'string': format('magenta'),
'string2': format('darkMagenta'),
'comment': format('darkGreen', 'italic'),
'self': format('black', 'italic'),
'numbers': format('brown'),
}
class PythonHighlighter (QSyntaxHighlighter):
"""Syntax highlighter for the Python language.
"""
# Python keywords
python_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',
]
# C keywords
c_keywords = [
'auto', 'break', 'case', 'char',
'const', 'continue', 'default', 'do',
'double', 'else', 'enum', 'extern',
'float', 'for', 'goto', 'if',
'int', 'long', 'register', 'return',
'short', 'signed', 'sizeof', 'static',
'struct', 'switch', 'typedef', 'union',
'unsigned', 'void', 'volatile', 'while'
]
# Python operators
operators = [
'=',
# Comparison
'==', '!=', '<', '<=', '>', '>=',
# Arithmetic
'\+', '-', '\*', '/', '//', '\%', '\*\*',
# In-place
'\+=', '-=', '\*=', '/=', '\%=',
# Bitwise
'\^', '\|', '\&', '\~', '>>', '<<',
]
# Python braces
braces = [
'\{', '\}', '\(', '\)', '\[', '\]',
]
def __init__(self, document, is_python=True):
QSyntaxHighlighter.__init__(self, 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 = (QRegExp("'''"), 1, STYLES['string2'])
self.tri_double = (QRegExp('"""'), 2, STYLES['string2'])
rules = []
# Keyword, operator, and brace rules
keywords = PythonHighlighter.python_keywords if is_python \
else PythonHighlighter.c_keywords
rules += [(r'\b%s\b' % w, 0, STYLES['keyword'])
for w in keywords]
rules += [(r'%s' % o, 0, STYLES['operator'])
for o in PythonHighlighter.operators]
rules += [(r'%s' % b, 0, STYLES['brace'])
for b in PythonHighlighter.braces]
# All other rules
rules += [
# 'self'
(r'\bself\b', 0, STYLES['self']),
# Double-quoted string, possibly containing escape sequences
(r'"[^"\\]*(\\.[^"\\]*)*"', 0, STYLES['string']),
# Single-quoted string, possibly containing escape sequences
(r"'[^'\\]*(\\.[^'\\]*)*'", 0, STYLES['string']),
# 'def' followed by an identifier
(r'\bdef\b\s*(\w+)', 1, STYLES['defclass']),
# 'class' followed by an identifier
(r'\bclass\b\s*(\w+)', 1, STYLES['defclass']),
# From '#' until a newline
(r'#[^\n]*', 0, STYLES['comment']),
# Numeric literals
(r'\b[+-]?[0-9]+[lL]?\b', 0, STYLES['numbers']),
(r'\b[+-]?0[xX][0-9A-Fa-f]+[lL]?\b', 0, STYLES['numbers']),
(r'\b[+-]?[0-9]+(?:\.[0-9]+)?(?:[eE][+-]?[0-9]+)?\b', 0, STYLES['numbers']),
]
# Add "//" to comments for C
if not is_python:
rules.append((r'//[^\n]*', 0, STYLES['comment']),)
# Build a QRegExp for each pattern
self.rules = [(QRegExp(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, format in self.rules:
index = expression.indexIn(text, 0)
while index >= 0:
# We actually want the index of the nth match
index = expression.pos(nth)
length = len(expression.cap(nth))
self.setFormat(index, length, format)
index = expression.indexIn(text, index + length)
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, delimiter, in_state, style):
"""Do 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
if self.previousBlockState() == in_state:
start = 0
add = 0
# Otherwise, look for the delimiter on this line
else:
start = delimiter.indexIn(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)
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
if __name__ == '__main__':
from PyQt5 import QtWidgets
app = QtWidgets.QApplication([])
editor = QtWidgets.QPlainTextEdit()
highlight = PythonHighlighter(editor.document())
editor.show()
# Load syntax.py into the editor for demo purposes
infile = open('PythonSyntax.py', 'r')
editor.setPlainText(infile.read())
app.exec_()