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[英]Parsing an equation erlang

原文 2015-02-27 06:57:29 4 1 erlang

I am learning erlang recently and I have a question. 我最近正在学习erlang，并且有一个问题。

I have an equation like this (~(2+1)). 我有一个像这样的方程（〜（2 + 1））。 I want to parse to polish notation? 我想解析波兰语符号吗？ For eg.{unaryMin{add,2,1}} 例如{unaryMin {add，2,1}}

How do I start? 我该如何开始？

1 个解决方案

If you want to parse something, from a simple formula to a programming language, you should start by learning about grammar , language and Compiler-compiler . 如果要解析从简单公式到编程语言的内容，则应先学习语法，语言和Compiler-compiler 。 Learning how to parse and translate/interpret something to another format is a very common task for any programmer (pretty much everything has a compiler/interpreter, even you image viewer, web browser, etc ...) so it's very important to learn about those things. 对于任何程序员来说，学习如何解析和翻译/解释为另一种格式都是非常常见的任务（几乎所有东西都有编译器/解释器，甚至您有图像查看器，Web浏览器等），因此了解这一点非常重要。那些事。

For Erlang, LYSE got a chapter about making a reverse-polish notation calculator here , and for converting from an infix equation to a prefix/postfix one, you should read about Shunt-Yard algorithm . 对于二郎，细胞溶解得到了有关使逆波兰式计算器章这里，并从缀公式转换为前缀/后缀一个，你应该阅读有关分流码算法。 Erlang also have is own version of yacc & lex : yecc , leex . Erlang也有自己的yacc和lex版本： yecc ， leex 。