YACC

Learning compile the principle and compile rules of the Lex and Yacc compiler tools, and to use the tool to generate the interpretation and compiler to compile the NC system PLC program.

学习并研究了Lex和Yacc这两个编译工具的编译原理和编译规则，并使用该工具生成的解释器和编译器编译出等离子切割机数控系统的PLC程序。

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You can just use an enum or a series of# define directives in a shared include file, or you can have yacc generate a list of predefined values for you.

您可以只是在一个共享的include文件中使用一个enum或者一系列define指令，或者您可以让yacc为您生成预定义值的一个列表。

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So, running two yacc actions is dangerous.

所以, 同时运行两个yacc动作是危险的.

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Old versions of yacc use files with fixed names. So, running two yacc actions is dangerous.

旧版本的yacc使用固定名字的文件. 所以, 同时运行两个yacc动作是危险的.

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Old versions of yacc use files with fixed names.

旧版本的yacc使用固定名字的文件.

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Programs using yacc, but not lex, are rarer.

使用yacc而不使用lex的程序比较罕见。

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yacc takes sets of tokens and assembles them into higher-level constructs, analogous to sentences.

yacc接受成组的记号，并将它们装配为高层次的结构，类似于句子。

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This means that if yacc would have to read two tokens before it knew which action to take, it would be unable to parse this grammar.

这就意味着，如果yacc在知道采取哪个动作之前，必须读取两个标记，那么它将无法解析该语法。

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