initial

1 files changed, 45 insertions, 0 deletions

diff --git a/pos.lua b/pos.lua
new file mode 100644
index 0000000..605ecbd
--- /dev/null
+++ b/pos.lua
@@ -0,0 +1,45 @@
+local class = require'r.class'
+
+local Pos = class()
+function Pos.new(cls)
+	return setmetatable({},cls)
+end
+function Pos.init(self,x,y)
+	self.x = x
+	self.y = y
+	return self
+end
+function Pos.make(cls,...)
+	return cls:new():init(...)
+end
+function Pos.__add(self,other)
+	return Pos:make(self.x+other.x,self.y+other.y)
+end
+function Pos.__sub(self,other)
+	return Pos:make(self.x-other.x,self.y-other.y)
+end
+function Pos.__mul(a,b)
+	if type(a) == "number" then
+		return Pos:make(a*b.x,a*b.y)
+	elseif type(b) == "number" then
+		return Pos:make(a.x*b,a.y*b)
+	else
+		error("can only multiply Pos by scalar")
+	end
+end
+function Pos.__div(a,b)
+	assert(type(b) == "number","can only divide Pos by scalar")
+	return a*(1/b)
+end
+function Pos.__eq(a,b) return a.x==b.x and a.y==b.y end
+function Pos.lensq(self) return self.x^2 + self.y^2 end
+function Pos.len(self) return math.sqrt(self:lensq()) end
+function Pos.norm(self) return self/self:len() end
+function Pos.dot(self,other) return self.x*other.x+self.y*other.y end
+function Pos.__tostring(self)
+	return string.format("(%.2f,%.2f)",self.x,self.y)
+end
+
+return Pos
+
+