samples: add Terra samples

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

samples/Terra/pattern.t

@@ -0,0 +1,43 @@
+
+terra foobar()
+    return 1,2
+end
+
+terra what()
+    var _,a,b = 1,foobar()
+    a,b = foobar()
+    return a + b
+end
+terra what2()
+    var a = foobar()
+    var b,c = unpackstruct(a)
+    return b+c
+end
+
+assert(what() == 3)
+assert(what2() == 3)
+
+
+struct A {
+    a : int
+    b : int
+}
+
+terra what3() : A
+    var a = A {1,2}
+    return unpacktuple(a)
+end
+assert(what3().b == 2)
+
+terra what4()
+    var a = A {1,2}
+    var c,d = unpackstruct(a)
+    return c+d
+end
+assert(what4() == 3)
+
+local terra ra() return A {1,2} end
+local a,b = unpackstruct(foobar())
+assert(a == 1 and b == 2)
+assert(unpacktuple(ra()).a == 1)
+assert(unpackstruct(ra()) == 1)