kuvia2/vendor/github.com/alecthomas/participle/v2/CHANGES.md
2022-01-15 00:09:03 +01:00

1.4 KiB

v2

v2 was released in November 2020. It contains the following changes, some of which are backwards-incompatible:

  • Added optional LexString() and LexBytes() methods that lexer definitions can implement to fast-path lexing of bytes and strings.

  • A new stateful lexer has been added.

  • A filename must now be passed to all Parse*() and Lex*() methods.

  • The text/scanner lexer no longer automatically unquotes strings or supports arbitary length single quoted strings. The tokens it produces are identical to that of the text/scanner package. Use Unquote() to remove quotes.

  • Tok and EndTok will no longer be populated.

  • If a field named Token []lexer.Token exists it will be populated with the raw tokens that the node parsed from the lexer.

  • Support capturing directly into lexer.Token fields. eg.

    type ast struct {
        Head lexer.Token   `@Ident`
        Tail []lexer.Token `@(Ident*)`
    }
    
  • Add an experimental/codegen for stateful lexers. This provides ~10x performance improvement with zero garbage when lexing strings.

  • The regex lexer has been removed.

  • The ebnf lexer has been removed.

  • All future work on lexing will be put into the stateful lexer.

  • The need for DropToken has been removed.