samples: add Terra samples

source: https://github.com/zdevito/terra/tree/master/tests

samples/Terra/arrayt.t

@@ -0,0 +1,75 @@
+C = terralib.includecstring [[
+	#include <stdio.h>
+	#include <stdlib.h>
+]]
+local arraytypes = {}
+function Array(T)
+	local struct ArrayImpl {
+		data : &T;
+		N : int;
+	}
+	function ArrayImpl.metamethods.__typename(self)
+	    return "Array("..tostring(T)..")"
+	end
+	arraytypes[ArrayImpl] = true
+	terra ArrayImpl:init(N : int)
+		self.data = [&T](C.malloc(N*sizeof(T)))
+		self.N = N
+	end
+	terra ArrayImpl:free()
+		C.free(self.data)
+	end
+	ArrayImpl.metamethods.__apply = macro(function(self,idx)
+		return `self.data[idx]
+	end)
+	ArrayImpl.metamethods.__methodmissing = macro(function(methodname,selfexp,...)
+		local args = terralib.newlist {...}
+		local i = symbol(int)
+		local promotedargs = args:map(function(a)
+			if arraytypes[a:gettype()] then
+				return `a(i)
+			else
+				return a
+			end
+		end)
+		return quote
+			var self = selfexp
+			var r : ArrayImpl
+			r:init(self.N)
+			for [i] = 0,r.N do
+				r.data[i] = self.data[i]:[methodname](promotedargs)
+			end
+		in
+			r
+		end
+	end)
+	return ArrayImpl
+end
+
+struct Complex {
+	real : float;
+	imag : float;
+}
+
+terra Complex:add(c : Complex) 
+	return Complex { self.real + c.real, self.imag + c.imag }
+end
+
+ComplexArray = Array(Complex)
+N = 10
+terra testit()
+	var ca : ComplexArray
+	ca:init(N)
+	for i = 0,N do
+		ca(i) = Complex { i, i + 1 }
+	end
+	var ra = ca:add(ca)
+	return ra
+end
+local r = testit()
+assert(r.N == N)
+for i = 0,N-1 do
+	assert(r.data[i].real == 2*i)
+	assert(r.data[i].imag == 2*(i+1))
+end
+assert(tostring(Array(int)) == "Array(int32)")