stanfordnlp/CoreNLP · error · java.lang.RuntimeException

Error parsing to sequence pattern

Error message

Error parsing  to sequence pattern

What it means

Env.getSequencePatternExpr resolves a variable to a sequence pattern expression; when the bound object is a String it parses it via TokenSequenceParser.parseSequence, and any parse failure is wrapped in a RuntimeException 'Error parsing <obj> to sequence pattern'.

Solutions

1. Inspect the wrapped cause for the parser's error location and fix the sequence syntax
2. Bind a SequencePattern/PatternExpr object directly instead of a string
3. Validate the expression in a standalone rule file before binding programmatically

Example fix

// before
env.bind("$pat", "{ word:/foo/ } { ");
// after
env.bind("$pat", "{ word:/foo/ }");

try { new TokenSequenceParser().parseSequence(env, seqString); } catch (Exception e) { throw new IllegalArgumentException("Not valid sequence syntax: " + seqString, e); }
env.bind(name, seqString);

try { PatternExpr pe = env.getSequencePatternExpr(name, true); } catch (RuntimeException e) { log.error("Bad sequence string for {}: {}", name, e.getMessage()); throw new IllegalArgumentException("Fix bound sequence: " + name, e.getCause()); }

When it happens

Trigger: env.bind(name, "...") with a string that is not valid TokensRegex sequence syntax, then using the variable in sequence position (getSequencePatternExpr / SeqVar evaluation).

Common situations: Rule strings with grammar errors (bad nesting, unbalanced brackets, invalid operators) bound programmatically; strings intended as literals not quoted/regex-escaped.

Related errors

• Invalid value for key:
• Unknown annotation key:
• Error parsing file:
• Error parsing to node pattern
• Invalid value for type

AI-assisted analysis of stanfordnlp/CoreNLP@1b7edd19c4 (2026-09-10). Data as JSON: /api/errors/65836bf2d74c7cc3. Report an issue: GitHub.

Appendix: source

Thrown at src/edu/stanford/nlp/ling/tokensregex/Env.java:371

    return null;
  }

  public SequencePattern.PatternExpr getSequencePatternExpr(String name, boolean copy) {
    Object obj = variables.get(name);
    if (obj != null) {
      if (obj instanceof SequencePattern) {
        SequencePattern seqPattern = (SequencePattern) obj;
        return seqPattern.getPatternExpr();
      } else if (obj instanceof SequencePattern.PatternExpr) {
        SequencePattern.PatternExpr pe = (SequencePattern.PatternExpr) obj;
        return (copy)? pe.copy():pe;
      } else if (obj instanceof NodePattern) {
        return new SequencePattern.NodePatternExpr( (NodePattern) obj);
      } else if (obj instanceof String) {
        try {
          return parser.parseSequence(this, (String) obj);
        } catch (Exception pex) {
          throw new RuntimeException("Error parsing " + obj + " to sequence pattern", pex);
        }
      } else {
        throw new Error("Invalid sequence pattern variable class: " + obj.getClass());
      }
    }
    return null;
  }

  public Object get(String name)
  {
      return variables.get(name);
  }

  // Functions for storing temporary thread specific variables
  //  that are used when running tokensregex

  public void push(String name, Object value) {
    Map<String,Object> vars = threadLocalVariables.get();

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