syntax_data: {"ast_node_type":"other","tokens":[{"end":48,"kind":"keyword","start":0,"text":"r12b:"}]}
source_snippet:         r12b: reg_byte = ["r12b"] % x86_64_only,
context_before:         r11b: reg_byte = ["r11b"] % x86_64_only,
context_after:         r13b: reg_byte = ["r13b"] % x86_64_only,