我正在解析一个由一系列行组成的相当简单的文件格式,每行都有一些空格分隔的字段,如下所示:
l 0x9823 1
s 0x1111 3
l 0x1111 12
?
我正在使用SWI-Prolog.这是我到目前为止的DCG:
:- consult(library(pure_input)).
load_trace(Filename, Traces) :-
phrase_from_file(trace_file_phrase(Traces), Filename).
trace_file_phrase([]) --> [].
trace_file_phrase([T|Ts]) --> trace_phrase(T), trace_file_phrase(Ts).
trace_phrase(access(Type, Address, SinceLast)) -->
access_type(Type), space,
address(Address), space,
nat(SinceLast), newline.
access_type(load) --> "l".
access_type(store) --> "s".
address(Number) --> "0x", hexnum(Number).
hexdigit(N) --> digit(N).
hexdigit(10) --> "a". hexdigit(11) --> "b". hexdigit(12) --> "c".
hexdigit(13) --> "d". hexdigit(14) --> "e". hexdigit(15) --> "f".
hexnum(N) --> hexdigit(D), hexnum(D, N).
hexnum(N, N) --> [].
hexnum(A, N) --> hexdigit(D), …