syntax_data: {"ast_node_type":"other","tokens":[{"end":30,"kind":"keyword","start":0,"text":"al:"}]}
source_snippet:         al: reg_byte = ["al"],
context_before:         r15: reg = ["r15", "r15w", "r15d"] % x86_64_only,
context_after:         ah: reg_byte = ["ah"] % high_byte,