highlight.py

def highlight_line(syntax, theme, line):
    ranges = []

    # Checks if rng is in any of the existing ranges
    # Ranges are tuples, (start, end, color)
    def inRange(rng):
        for r in ranges:
            if rng[0] >= r[0] and rng[1] <= r[1]:
                return True
        return False

    for s in syntax:
        rx, name = s
        color = theme[name]
        match = rx.match(line)

        # Loop through the matches for this particular syntax regex
        for match in re.finditer(rx, line):
            rng = match.span()
            
            # Append the range and color if it's not in an existing range
            if not inRange(rng):
                ranges.append((rng[0], rng[1], color))

    # Sort the ranges based on their start value
    ranges.sort(key=lambda r: r[0])

    # Loop through the line
    i = 0
    while i < len(line):
        
        # If ranges[0][0] (`start` of the first range) matches i,
        # write line[start:end] appropriately colored, and put i after the end of the range
        if len(ranges) > 0 and ranges[0][0] == i:
            start, end, color = ranges.pop(0)
            sys.stdout.write(colorize(line[start:end], color))
            i = end
            
        # Otherwise, just write a character
        else:
            sys.stdout.write(line[i])
            i += 1

    sys.stdout.write("\n")