[stdlib] add optional default value for table and struct call

anselme/stdlib/script.lua

@@ -7,7 +7,7 @@ return [[
 	:resume target = ()
 
 	fn.:check = $(anchor::is anchor)
-		fn.reached(anchor) = (fn.reached(anchor) | 0) + 1
+		fn.reached(anchor) = fn.reached(anchor, 0) + 1
 	fn.:checkpoint = $(anchor::is anchor, on resume=attached block(default=()))
 		:resuming = resuming(1) /* calling function is resuming */
 		if(on resume)
@@ -15,12 +15,12 @@ return [[
 			if(resume target == anchor | resuming)
 				on resume!
 			else!
-				fn.reached(anchor) = (fn.reached(anchor) | 0) + 1
+				fn.reached(anchor) = fn.reached(anchor, 0) + 1
 				merge branch!
 		else!
 			fn.current checkpoint = anchor
 			if(resume target != anchor)
-				fn.reached(anchor) = (fn.reached(anchor) | 0) + 1
+				fn.reached(anchor) = fn.reached(anchor, 0) + 1
 				merge branch!
 
 	:f = $

anselme/stdlib/structures.lua

@@ -112,6 +112,16 @@ return {
 			return s:get(k)
 		end
 	},
+	{
+		"_!", "(s::is struct, key, default)",
+		function(state, s, k, default)
+			if s:has(k) then
+				return s:get(k)
+			else
+				return default
+			end
+		end
+	},
 	{
 		"has", "(s::is struct, key)",
 		function(state, s, k)
@@ -137,6 +147,16 @@ return {
 			return t:get(state, key)
 		end
 	},
+	{
+		"_!", "(t::is table, key, default)",
+		function(state, t, key, default)
+			if t:has(state, key) then
+				return t:get(state, key)
+			else
+				return default
+			end
+		end
+	},
 	{
 		"_!", "(t::is table, key) = value",
 		function(state, t, key, value)

test/tests/map index accross checkpoints.ans

@@ -27,6 +27,6 @@
 
 	x={4}
 
-	|no={a(x)}
+	|no={a(x,())}
 
 f!