stanfordnlp/CoreNLP · error · IllegalArgumentException

Not a valid dashes style:

Error message

Not a valid dashes style: 

What it means

SpanishLexer throws this IllegalArgumentException when the 'dashes' option value does not match any constant of LexerUtils.DashesEnum. The value is trimmed, uppercased, and passed to Enum.valueOf; unrecognized names are rethrown with this message at lexer construction time.

Solutions

1. Set dashes to a valid LexerUtils.DashesEnum constant name (e.g. "none", "unicode", "ptb").
2. Verify the accepted values in LexerUtils.DashesEnum for your CoreNLP version.
3. Validate the value with LexerUtils.DashesEnum.valueOf(value.trim().toUpperCase(Locale.ROOT)) in a try-catch before construction.
4. Avoid hyphenated or descriptive values — only exact enum names are accepted.

Example fix

// before
props.put("dashes", "hyphens");
// after
props.put("dashes", "unicode");

// before constructing SpanishLexer
String v = options.get("dashes");
if (v != null) {
  try { LexerUtils.DashesEnum.valueOf(v.trim().toUpperCase(Locale.ROOT)); }
  catch (IllegalArgumentException e) { throw new IllegalArgumentException("bad dashes value: " + v); }
}

try {
  lex = new SpanishLexer(reader, tf, options);
} catch (IllegalArgumentException e) {
  if (e.getMessage().contains("Not a valid dashes style")) {
    options.put("dashes", "ptb");
    lex = new SpanishLexer(reader, tf, options);
  } else throw e;
}

When it happens

Trigger: Constructing SpanishLexer with an options map entry key="dashes" and a value such as "hyphen", "emdash", or "dashes" instead of a valid DashesEnum constant (typically NONE, UNICODE, PTB).

Common situations: Hand-edited CoreNLP tokenizer properties; translating PTBTokenizer dash options into SpanishLexer without checking its enum vocabulary; typos or renamed constants across versions.

Understand the failure class

Background: Invalid enum value errors: "Unknown type", "Invalid scope", "must be one of" — when a string is not on the library's allowed list — this error's family across 23 libraries.

Related errors

• Not a valid ellipses style:
• Not a valid dashes style:
• Not a valid ellipses style:
• Unknown LogPriorType:
• Not a valid ellipses style:

AI-assisted analysis of stanfordnlp/CoreNLP@1b7edd19c4 (2026-09-10). Data as JSON: /api/errors/c2f99ff39d2398d1. Report an issue: GitHub.

Appendix: source

Thrown at src/edu/stanford/nlp/international/spanish/process/SpanishLexer.flex:150

          } else if ("normalizeAmpersandEntity".equals(key)) {
            normalizeAmpersandEntity = val;
          } else if ("normalizeFractions".equals(key)) {
            normalizeFractions = val;
          } else if ("normalizeParentheses".equals(key)) {
            normalizeParentheses = val;
          } else if ("normalizeOtherBrackets".equals(key)) {
            normalizeOtherBrackets = val;
          } else if ("ellipses".equals(key)) {
            try {
              ellipsisStyle = LexerUtils.EllipsesEnum.valueOf(value.trim().toUpperCase(Locale.ROOT));
            } catch (IllegalArgumentException iae) {
              throw new IllegalArgumentException ("Not a valid ellipses style: " + value);
            }
          } else if ("dashes".equals(key)) {
            try {
              dashesStyle = LexerUtils.DashesEnum.valueOf(value.trim().toUpperCase(Locale.ROOT));
            } catch (IllegalArgumentException iae) {
              throw new IllegalArgumentException ("Not a valid dashes style: " + value);
            }
          } else if ("escapeForwardSlashAsterisk".equals(key)) {
            escapeForwardSlashAsterisk = val;
          } else if ("untokenizable".equals(key)) {
            switch (value) {
              case "noneDelete":
                untokenizable = UntokenizableOptions.NONE_DELETE;
                break;
              case "firstDelete":
                untokenizable = UntokenizableOptions.FIRST_DELETE;
                break;
              case "allDelete":
                untokenizable = UntokenizableOptions.ALL_DELETE;
                break;
              case "noneKeep":
                untokenizable = UntokenizableOptions.NONE_KEEP;
                break;
              case "firstKeep":

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