Yield the origin text as column name

[Shylock-Hg]

Is your feature request related to a problem? Please describe.

Now our column name is generated by expression toString, this maybe is different from origin expression literal.

Describe the solution you'd like

Get the origin expression literal by bison location.

Describe alternatives you've considered

Additional context

[Shylock-Hg]

In lex rule {DEC}+\.\., the yyless call will lead to duplicate counting of column index. YY_USER_ACTION call before user action, so extra columns counted.