Antlr 词法分析器规则标记浮点/双精度

Question

我正在尝试使用 这个正则表达式 来标记 Antlr 中的双精度值，但显然这个正则表达式没有被 Antlr 理解。

Number: (-?)(0|([1-9][0-9]*))(\\.[0-9]+)?;

错误：

syntax error: '-' came as a complete surprise to me 
syntax error: '?' came as a complete surprise to me
syntax error: '0' came as a complete surprise to me
syntax error: '\' came as a complete surprise to me 
syntax error: '\' came as a complete surprise to me 
syntax error: '-' came as a complete surprise to me 
syntax error: '?' came as a complete surprise to me
syntax error: '0' came as a complete surprise to me
syntax error: '\' came as a complete surprise to me 
syntax error: '\' came as a complete surprise to me

Answer 1

Antlr Lexer统治在某种程度上类似于Regex，但绝对不是正则。

尝试：

Number: '-'?('0'|[1-9][0-9]*)('.'[0-9]+)?;

字符需要包含在'标记中（除了集符号（[ and ]之间的字符，] ）