As far as I can tell this is a bad error message but `MyGraph.Node` is not
valid. The tests contain
import math
type
Node* = concept n
`==`(n, n) is bool
Graph1* = concept g
type N = Node
distance(g, N, N) is float
Graph2 = concept g
distance(g, Node, Node) is float
Graph3 = concept g
var x: Node
distance(g, x, x) is float
XY* = tuple[x, y: int]
MyGraph* = object
points: seq[XY]
static:
assert XY is Node
proc distance*( g: MyGraph, a, b: XY): float =
sqrt( pow(float(a.x - b.x), 2) + pow(float(a.y - b.y), 2) )
static:
assert MyGraph is Graph1
assert MyGraph is Graph2
assert MyGraph is Graph3
as a starting point for how to model graphs. Not sure if that's helpful.
