MathHead_E mathematical expression parser for the preparation of their own use of calculators!
数学表达式解析器，适合编写自己使用的计算器！
Here's a sample application that instantiates your parser and feeds it an expression that you hardwired in at the top of the app.
下面是一个样本应用程序，它实例化您的解析器，并且为它提供了一个硬连接在应用程序顶部的表达式。
Finally, for the case of recursive expressions, the parser should simply echo parentheses when it sees them within the expression recursion, as illustrated in Listing 21.
最后对于递归表达式的情况，当解析器在表达式递归中看到括号时，就应该简单地进行回送，如清单21中所示。
If it returns an, the entire expression consists of a single integer, is valid, and the parser returns control to the calling application.
如果返回，则由单个整数构成的整个表达式都是有效的，解析器将控制返还给调用应用程序。
If all you need to do with an XML file is grab some text from within a single node, it might be possible to use a simple regular expression that will probably operate faster than any XML parser.
如果对XML文件所做的全部操作只是从单个节点获取一些文本，可以使用一个简单的正则表达式，其处理速度可能会比任何xml解析器都快。
The additional text analysis performed by the regular expression annotator does have a performance impact and will reduce the maximum parser throughput.
由正则表达式注释器执行的额外文本分析会影响性能，会降低解析器的最大吞吐量。
The schema parser must have support for regular expression facets.
模式解析器必须支持正则表达式。
When it comes to parser generators, Parsing Expression Grammars (PEG) have become quite popular recently after a thesis by Bryan Ford introduced an optimization called "Packrat Parsing".
当谈到解析器生成器的时候，解析表达式语法（PEG）最近因为一篇BryanFord介绍的一种叫做“Packrat解析”优化的论文而变得很流行。
You can then call the new parser from your application code, passing it an expression to evaluate.
然后可以从您的应用程序代码调用新的解析器，从而将表达式传递给它进行求值。
If it encounters one, the expression is valid and the parser is done.
如果遇到一个整数，则表达式是有效的，解析器将完成工作。
If the parser finds anything other than these three tokens during its scan, the expression it's scanning is considered invalid.
如果解析器在其扫描期间发现了除这三个记号外的任何其它记号，则认为它正在扫描的表达式是无效的。
Every regular expression is logically equivalent to a state machine, and the parser of every regular expression implements a state machine.
逻辑上，每个规则表达式都等价于一个状态机，而每个规则表达式的语法分析器都实现这个状态机。
When an expression is being parsed, the parser should emit the word "INTERSECT" whenever it parses "and" and "UNION" whenever it parses "or".
在解析一个表达式的时候，解析器每当解析“AND”时就发出字“INTERSECT”，而解析“OR”时就发出“UNION”。
You could use an XML parser to read out the tags, but it's easier in this case to use a regular expression.
可以使用XML解析器读出标记，但在本例中使用一个正则表达式会更为容易。
It can also take actions; blocks of code enclosed in pairs will be executed when the parser reaches that point in an expression. For instance, one might write.
它还可以采取动作；当解析器达到表达式中的那个条件点时，封装在中的代码块将会被执行。
If the expression you're passing in to the parser code can't be legally constructed according to the grammar, either a ParseException or a LexicalError is thrown.
如果正在传递给解析器代码的表达式不能根据语法合法地构造，则将抛出ParseException或LexicalError。
The OCL parser at the bottom of the OCL expression editor confirms that the syntax is okay and that you’re returning a collection.
在OCLexpressioneditor底部的 OCL解析器能确认语法是否正确以及是否返回了一个集合。
Finally, for the case of recursive expressions, the parser should simply echo parentheses when it sees them within the expression recursion , as illustrated in Listing 21.
最后对于递归表达式的情况，当解析器在表达式递归中看到括号时，就应该简单地进行回送，如清单21中所示。
Finally, for the case of recursive expressions, the parser should simply echo parentheses when it sees them within the expression recursion , as illustrated in Listing 21.
最后对于递归表达式的情况，当解析器在表达式递归中看到括号时，就应该简单地进行回送，如清单21中所示。
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