syntax_data: {"ast_node_type":"other","tokens":[{"end":49,"kind":"keyword","start":0,"text":".map(|&[fst,"}]}
source_snippet:                     .map(|&[fst, snd]| snd - fst)
context_before:                     .array_windows()
context_after:                     .map(|bp| bp.to_usize())