在 prolog 中读取文件 [英] Reading a file in prolog

问题描述

可能重复:
在Prolog中逐行读取文件

我发现以下序言代码一次读取一个字符并打印出来.

I found the following prolog code which reads one character at a time and prints out.

process(File) :-
        open('C:/Users/BHARAT/Desktop/a.txt', read, In),
        get_char(In, Char1),
        process_stream(Char1, In),
        close(In).

process_stream(end_of_file, _) :- !.
process_stream(Char, In) :-
        print(Char),
        get_char(In, Char2),
        process_stream(Char2, In).

但是如果文件有多行，有没有办法一次读取一整行，以便标记化.

But if the file has multiple lines is there a way to read 1 whole line at a time so that it will be easy for tokenizing.

推荐答案

你说你想对输入进行标记 - 最好的方法是明确的子句语法 (DCG).使用 SWI 中的 library(pio) 您可以直接使用语法读取文件，如下所示:

You say you want to tokenize the input - the best way to do this are definite clause grammars (DCGs). With library(pio) in SWI you can use the grammar directly to read in a file like so:

?- use_module(library(pio)).
?- phrase_from_file(seq(Xs),f).

seq([]) --> [].
seq([E|Es]) --> [E], seq(Es).

现在用更精细的分词器替换 seq//1.

Replace now seq//1 by some more elaborate tokenizer.

这篇关于在 prolog 中读取文件的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！