为具有一个字符的标识符定义antlr规则 [英] Defining antlr rule for identifiers with one character

问题描述

我喜欢定义一个非常简单的规则，该规则应代表标识符.这对于长度超过一个字符的标识符非常有效，但是对于仅具有一个字符的标识符，我得到一个MismatchedTokenException(64！= 45).这是规则:

ID:('a'..'z'|'A'..'Z')+ ;

这有什么问题?

谢谢！

解决方案

您是完全正确的，规则本身很好，但是我发现ANTLR中的很多内容都取决于规则的顺序.我之前有另一个规则，该规则已经与ID规则匹配.最终这是有道理的，因为Lexer无法决定采用哪个规则.

谢谢！

i like to define a very simple rule, which should represent identifiers. This works quite well for identifiers which are longer than one characters, but for identifiers with exactly one character I get a MismatchedTokenException(64!=45). This is the rule:

ID : ('a'..'z' | 'A'..'Z')+ ;

What is wrong with that?

Thanks!

解决方案

You're absolutely right, the rule on its own is fine, but I figured out that a lot in ANTLR depends on the order of rules. I had another rule before, which did already match the ID rule. Finally it makes sense, because the Lexer cannot decide which rule to take.

Thanks!

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