samples: add Terra samples

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

samples/Terra/constant.t

@@ -0,0 +1,35 @@
+
+
+local foo = terralib.constant(terralib.new(int[4],{1,2,3,4}))
+
+struct A {
+	a : int;
+	b : float
+}
+
+local mystr = terralib.new(A,{3,4.5})
+local const = constant(mystr)
+
+
+terra bar()
+	return foo[3] + mystr.a
+end
+
+terra bar2()
+	return foo[1] + mystr.b
+end
+
+function wrapper(a)
+	return a + 1
+end
+
+local p1 = terralib.constant(int -> int, wrapper)
+
+terra doit()
+	return p1(3)
+end
+
+local test = require("test")
+test.eq(bar(),7)
+test.eq(bar2(),6.5)
+test.eq(doit(),4)