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16.4 Iterating through the trees

Function: int marpa_t_next ( Marpa_Tree t)

Positions t at the next parse tree in the iteration. Tree iterators are initialized to the position before the first parse tree, so this method must be called before creating a valuator from a tree.

If a tree iterator is positioned after the last parse, the tree is said to be “exhausted”. A tree iterator for a bocage with no parse trees is considered to be “exhausted” when initialized. If the tree iterator is exhausted, marpa_t_next() returns -1 as a termination indicator, and sets the error code to MARPA_ERR_TREE_EXHAUSTED.

Return value: On success, a non-negative value. If the tree iterator is exhausted, -1. On failure, -2.

Function: int marpa_t_parse_count ( Marpa_Tree t)

The parse counter counts the number of parse trees traversed so far. The count includes the current iteration of the tree, so that a value of 0 indicates that the tree iterator is at its initialized position, before the first parse tree.

Return value: The number of parses traversed so far. Always succeeds.