Some builtins are unnecessarily special (fix #521)

tests/all.test

@@ -246,6 +246,51 @@ null
 10
 [0,9,0,5,"nth doesn't support negative indices"]
 
+#
+# Check that various builtins evalute all arguments where appropriate,
+# doing cartesian products where appropriate.
+#
+
+# Check that limit does work for each value produced by n!
+[limit(5,7; range(9))]
+null
+[0,1,2,3,4,0,1,2,3,4,5,6]
+
+# Same check for nth
+[nth(5,7; range(9;0;-1))]
+null
+[4,2]
+
+# Same check for range/3
+[range(0,1,2;4,3,2;2,3)]
+null
+[0,2,0,3,0,2,0,0,0,1,3,1,1,1,1,1,2,2,2,2]
+
+# Same check for range/1
+[range(3,5)]
+null
+[0,1,2,0,1,2,3,4]
+
+# Same check for index/1, rindex/1, indices/1
+[(index(",","|"), rindex(",","|")), indices(",","|")]
+"a,b|c,d,e||f,g,h,|,|,i,j"
+[1,3,22,19,[1,5,7,12,14,16,18,20,22],[3,9,10,17,19]]
+
+# Same check for join/1
+join(",","/")
+["a","b","c","d"]
+"a,b,c,d"
+"a/b/c/d"
+
+# Same check for flatten/1
+flatten(-1,3,2,1)
+[0, [1], [[2]], [[[3]]]]
+[0,[1],[[2]],[[[3]]]]
+[0,1,2,3]
+[0,1,2,[3]]
+[0,1,[2],[[3]]]
+
+
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 # Slices
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