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For compound hash tables such as the future StringHashMap, an iterator-based API might be inefficient for iterating over a table or for merging two tables, because: 1) the key has to be converted to a general format from a from a component-specific format, which may differ between the components; 2) the information about the component of the compound hash table to which the value belongs is lost, and has to be recalculated if the value is reinserted. A more efficient approach is to use internal iteration, that is, map-like functions, which avoids unnecessary conversions when iterating, and allows to use an efficient component-wise approach when merging. |
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