8 Unsafe for Clause Transforms
The syntax/unsafe/for-transform module provides a helper function that gives access to the sequence transformers defined by define-sequence-syntax. This is what the for forms use and enables faster sequence traversal than what the sequence interface provides.
The output may use unsafe operations.
(([(outer-id ...) outer-expr] ...) outer-check ([loop-id loop-expr] ...) pos-guard ([(inner-id ...) inner-expr] ...) pre-guard post-guard (loop-arg ...))
which can then be spliced into the appropriate iterations. See :do-in for more information.
The result may use unsafe operations.
The first argument orig-stx is used only for reporting syntax errors.