syntax_data: {"ast_node_type":"variable","tokens":[{"end":47,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:                 let linebpos = self.lines()[a];
context_before:                 let line = a + 1; // Line numbers start at 1
context_after:                 let linechpos = self.bytepos_to_file_charpos(linebpos);