从单独的程序调用 lex/yacc
我一直在阅读 lex/yacc 。这些书籍和示例并不难理解。事实上，整个概念一清二楚。但有一个例外。 Lex/yacc 似乎生成独立的程序。如果我想将它们作为解析器函数调用怎么办？ Yacc 似乎生成了一个 main 函数，那么我如何从自己的函数中调用而不发生冲突。
目前我还不清楚它们如何处理文件输入。我可以从文件中抓取一行并将其发送到解析器，但是如果您的解析器正在寻找多行结构（例如用大括号括起来的块）怎么办？
我意识到我对这两件事都很愚蠢，但我们将不胜感激。谢谢。
I've been reading up on lex/yacc. The books and examples are not hard to follow. In fact, the whole concept is clear as a bell. With one exception. Lex/yacc seem to generate standalone programs. What if I wanted to call them as a parser function? Yacc seems to generate a main function, so how would I call from my own without conflicts.
I'm also unclear at this point how they operate on file input. I'm okay with grabbing a line from a file and sending it to the parser, but what if your parser is looking for a multi-line structure like a block enclosed in braces?
I realize I'm being stupid about both of these, but any help is appreciated. Thanks.
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lexx / yacc 组合的输入是通过名为 yyin 的 FILE * 进行的。
默认为 stdin - 围绕 lex.yy.c 进行搜索以找到它，
如果您将 FILE * 分配给 yyin，词法分析器将从该文件中读取，您可以执行类似
yyin = fopen ("parseme", "rt"); 的操作；
在调用 yyparse() 之前，通常在 main() 中。
input to the lexx / yacc combo is via a FILE * called yyin.
this defaults to stdin - trawl around lex.yy.c to find it
if you assign a FILE * to yyin, the lexer will read from that file, you do something like
yyin = fopen ("parseme", "rt");
before the call to yyparse(), typically in your main().
这两个程序都会生成
yylex()和yyparse()函数，但都不会生成 main 函数。您必须在某处添加您自己的main()函数。许多教程将它们放入 .l 或 .y 文件中，但您可以随意将它们放在您想要的位置。Both programs generate the
yylex()andyyparse()functions, but none of them generates a main function. You have to add your ownmain()function somewhere. Many tutorials place them into the .l or .y file, but you are free to place them where ever you want.