samples: add Terra samples

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

samples/Terra/defercond.t

@@ -0,0 +1,82 @@
+c = global(int,0)
+
+terra up()
+    c = c + 1
+end
+
+terra foo()
+    var a = 0
+    while([quote do defer up() end in a < 10 end]) do
+        a = a + 1
+    end
+end
+
+foo()
+assert(c:get() == 11)
+
+terra foo2()
+    var a = 0
+    while(a < 10 and [quote do defer up() end in true end]) do
+        a = a + 1
+    end
+end
+
+foo2()
+assert(c:get() == 21)
+
+terra foo3()
+    var a = 0
+    while true do
+        var r = a < 10 and [quote do defer up() end in true end]
+        if not r then break end
+        a = a + 1
+    end
+end
+foo3()
+assert(c:get() == 31)
+
+function failit(match,fn)
+	local success,msg = pcall(fn)
+	if success then
+		error("failed to fail.",2)
+	elseif not string.match(msg,match) then
+		error("failed wrong: "..msg,2)
+	end
+end
+local df = "defer statements are not allowed in conditional expressions"
+failit(df,function()
+    local terra foo()
+        if [quote defer up() in true end] then end
+    end
+    foo()
+end)
+failit(df,function()
+    local terra foo()
+        while [quote defer up() in true end] do end
+    end
+    foo()
+end)
+failit(df,function()
+    local terra foo()
+        repeat until [quote defer up() in true end] do end
+    end
+    foo()
+end)
+failit(df,function()
+    local terra foo()
+        var a = true or [quote defer up() in true end]
+    end
+    foo()
+end)
+
+failit(df,function()
+    local terra foo()
+        var a = [quote defer up() in true end] and true
+    end
+    foo()
+end)
+    local terra foo()
+        var a = [quote defer up() in 1 end] and 2
+    end
+    foo()
+    assert(c:get() == 32)