MapExp Class

Map expression generator. See Exp.

The bin expression argument in these methods can be a reference to a bin or the result of another expression. Expressions that modify bin values are only used for temporary expression evaluation and are not permanently applied to the bin.

Map modify expressions return the bin's value. This value will be a map except when the map is nested within a list. In that case, a list is returned for the map modify expression.

All maps maintain an index and a rank. The index is the item offset from the start of the map, for both unordered and ordered maps. The rank is the sorted index of the value component. Map supports negative indexing for index and rank.

Index examples:

• Index 0: First item in map.
• Index 4: Fifth item in map.
• Index -1: Last item in map.
• Index -3: Third to last item in map.
• Index 1 Count 2: Second and third items in map.
• Index -3 Count 3: Last three items in map.
• Index -5 Count 4: Range between fifth to last item to second to last item inclusive.

Rank examples:

• Rank 0: Item with lowest value rank in map.
• Rank 4: Fifth lowest ranked item in map.
• Rank -1: Item with highest ranked value in map.
• Rank -3: Item with third highest ranked value in map.
• Rank 1 Count 2: Second and third lowest ranked items in map.
• Rank -3 Count 3: Top three ranked items in map.

Nested expressions are supported by optional CTX context arguments. Example:

• bin = {key1={key11=9,key12=4}, key2={key21=3,key22=5}}
• Set map value to 11 for map key "key21" inside of map key "key2".
• Get size of map key2.
• MapExp.size(Exp.MapBin("bin"), CTX.mapKey(Value.get("key2"))
• result = 2

public sealed class MapExp