decorator version

LLine.py

def add_last_vertex(f):
    """Call a function with the newest vertex of the workplane as the first argument.

    For example, add_last_vertex(Line)(p) is equivalent to Line((0,0), p),
    if there was no last vertex, or if the last vertex was (0,0)
    """
    def wrapped(*args, **kwargs):
        context = Builder._get_context()
        loclastpt = Vector()
        try:
            lastpt = context.edges().vertices()[-1]
            loclastpt = context.workplanes[-1].to_local_coords(lastpt)
        except:
            pass
        return f(loclastpt, *args, **kwargs)
    return wrapped

def add_accum(f):
    """Turns the argument sequence of offsets into a sequence of points.
    For example, add_accum(Line)((1,2), (3,4)) becomes Line((1,2), (4,6))"""
    def wrapped(*args, **kwargs):
        def add_vec(a,b):
            return Vector(a) + Vector(b)
        # TODO only accumulate points that are int/float/VectorLike?
        pts = itertools.accumulate(flatten_sequence(*args), add_vec)
        return f(*pts, **kwargs)
    return wrapped

def add_zero_x(f):
    """Call a function with a sequence of int/float instead of
    a sequence of (0,y) tuples.

    For example, add_zero_x(Line)(1,2) becomes Line((0,1), (0,2))
    """
    def wrapped(*args, **kwargs):
        def as_y(y):
            if isinstance(y, float) or isinstance(y, int):
                return (0,y)
            else:
                return y
        pts = map(as_y, flatten_sequence(*args))
        return f(*pts, **kwargs)
    return wrapped

# relative lines that start at the last point
@add_last_vertex
@add_accum
def rline(*args, **kwargs):
    """rline uses relative coordinates to draw a line
    starting at the previous vertex

    rline(3) is a horizontal line 3 units long
    rline((0,3)) is a vertical line, vrline(3) is preferable
    rline((3,3)) is a diagonal line
    rline(3, (0,3), 3, (0,3)) is a zigzag
    """
    Line(*args, **kwargs)

@add_zero_x
@add_last_vertex
@add_accum
def vrline(*args, **kwargs):
    Line(*args, **kwargs)
    
# absolute lines that start at the last point

@add_zero_x
@add_last_vertex
def vline(*args, **kwargs):
    """vline(y) draws a line to the (0, y) point from the last vertex

    rather uselessly can take more than two parameters, ie

    vline(1,2,3) is no different than vline(1,3)
    """
    Line(*args, **kwargs)

@add_last_vertex
def line(*args, **kwargs):
    """draw a line from the last vertex to the given absolute coordinate"""
    Line(*args, **kwargs)