samples: add Terra samples

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

samples/Terra/let2.t

@@ -0,0 +1,64 @@
+
+
+local a = 
+quote
+	var b = 1
+in
+	b + 0, b + 1
+end
+
+terra f0()
+	return (a)
+end
+terra f1()
+	return a
+end
+terra f2()
+	a
+end
+local test = require("test")
+test.meq({1,2},f0())
+test.meq({1,2},f1())
+
+local c = symbol()
+local b = 
+quote
+	var [c]  = 3
+in
+	c,c+1
+end
+
+terra f3()
+	b
+	return ([c])
+end
+assert(f3() == 3)
+
+a = global(1)
+local emptyexp = quote
+	a = a + 1
+end
+
+local emptystmts = {4,3}
+
+local both = quote
+in 4,[quote a = a + 1 in 3 end]
+end
+
+terra bar(a : int,  b : int)
+	return a + b
+end
+terra bar2(a : int,  b : int, c : {})
+	return a + b
+end
+terra f4()
+	return bar(emptystmts) + bar2(1,2,emptyexp) + a
+end
+
+assert(f4() == 12)
+
+terra f5()
+	return bar(both._0,both._0) + a
+end
+
+assert(f5() == 12)