Method exec

src/main/java/net/starlark/java/eval/Eval.java:286–327

(StarlarkThread.Frame fr, Statement st)

  }

  private static TokenKind exec(StarlarkThread.Frame fr, Statement st)
      throws EvalException, InterruptedException {
    if (fr.dbg != null) {
      Location loc = st.getStartLocation(); // not very precise
      fr.setLocation(loc);
      fr.dbg.before(fr.thread, loc); // location is now redundant since it's in the thread
    }

    if (++fr.thread.steps >= fr.thread.stepLimit) {
      throw new EvalException("Starlark computation cancelled: too many steps");
    }

    switch (st.kind()) {
      case ASSIGNMENT:
        execAssignment(fr, (AssignmentStatement) st);
        return TokenKind.PASS;
      case EXPRESSION:
        eval(fr, ((ExpressionStatement) st).getExpression());
        return TokenKind.PASS;
      case FLOW:
        return ((FlowStatement) st).getFlowKind();
      case FOR:
        return execFor(fr, (ForStatement) st);
      case DEF:
        DefStatement def = (DefStatement) st;
        StarlarkFunction fn = newFunction(fr, def.getResolvedFunction());
        assignIdentifier(fr, def.getIdentifier(), fn);
        return TokenKind.PASS;
      case IF:
        return execIf(fr, (IfStatement) st);
      case LOAD:
        execLoad(fr, (LoadStatement) st);
        return TokenKind.PASS;
      case RETURN:
        return execReturn(fr, (ReturnStatement) st);
      case TYPE_ALIAS:
        return TokenKind.PASS;
      case VAR:
        return TokenKind.PASS;
    }
    throw new IllegalArgumentException("unexpected statement: " + st.kind());
  }

  /**
   * Updates the environment bindings, and possibly mutates objects, so as to assign the given value