Multi-line closures in Gremlin script & function definitions

[amergin]

Regular expression fetching the functions seems to be faulty:

bash-4.1$ cat short2.groovy 
def short2()
{
    return g.v(1234).outE.filter
    {
        return (it.pvalue > 0) ||
        (it.correlation < 0);
    };
}

>>> g.scripts.update('short2.groovy')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/lineo4j/.local/lib/python2.7/site-packages/bulbs/groovy.py", line 69, in update
    methods = self._get_methods(file_path)
  File "/home/lineo4j/.local/lib/python2.7/site-packages/bulbs/groovy.py", line 89, in _get_methods
    return Parser(file_path).get_methods()
  File "/home/lineo4j/.local/lib/python2.7/site-packages/bulbs/groovy.py", line 184, in __init__
    Scanner(handlers).scan(groovy_file)
  File "/home/lineo4j/.local/lib/python2.7/site-packages/bulbs/groovy.py", line 175, in scan
    self.get_item(fin,line)
  File "/home/lineo4j/.local/lib/python2.7/site-packages/bulbs/groovy.py", line 166, in get_item
    callback(self,content)
  File "/home/lineo4j/.local/lib/python2.7/site-packages/bulbs/groovy.py", line 192, in add_method
    method_signature = self._get_method_signature(method_definition)
  File "/home/lineo4j/.local/lib/python2.7/site-packages/bulbs/groovy.py", line 206, in _get_method_signature
    return re.search(pattern,method_definition).group(1).strip()
AttributeError: 'NoneType' object has no attribute 'group'

This seems to be due to \n between def [functionname] and '{' because removing it will remove the problem:

bash-4.1$ cat short.groovy 
def short() {
    return g.v(1234).outE.filter
    {
        return (it.pvalue > 0) ||
        (it.correlation < 0);
    };
}

>>> g.scripts.update('short.groovy')
>>> 

---

Seems there's also a problem with closures split to several lines:

>>> s = g.scripts.get('short')
>>> g.gremlin.query(s)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/lineo4j/.local/lib/python2.7/site-packages/bulbs/gremlin.py", line 62, in query
    resp = self.client.gremlin(script, params)
  File "/home/lineo4j/.local/lib/python2.7/site-packages/bulbs/neo4jserver/client.py", line 384, in gremlin
    return self.request.post(path, params)
  File "/home/lineo4j/.local/lib/python2.7/site-packages/bulbs/rest.py", line 126, in post
    return self.request(POST, path, params)
  File "/home/lineo4j/.local/lib/python2.7/site-packages/bulbs/rest.py", line 181, in request
    return self.response_class(http_resp, self.config)
  File "/home/lineo4j/.local/lib/python2.7/site-packages/bulbs/neo4jserver/client.py", line 217, in __init__
    self.handle_response(response)
  File "/home/lineo4j/.local/lib/python2.7/site-packages/bulbs/neo4jserver/client.py", line 249, in handle_response
    response_handler(response)
  File "/home/lineo4j/.local/lib/python2.7/site-packages/bulbs/rest.py", line 36, in bad_request
    raise ValueError(http_resp)
ValueError: ({'status': '400', 'content-length': '1122', 'content-encoding': 'UTF-8', 'server': 'Jetty(6.1.25)', 'access-control-allow-origin': '*', 'content-type': 'application/json'}, '{\n  "message" : "org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:\\nScript26.groovy: 90: Ambiguous expression could be a parameterless closure expression, an isolated open code block, or it may continue a previous statement;\\n   solution: Add an explicit parameter list, e.g. {it -> ...}, or force it to be treated as an open block by giving it a label, e.g. L:{...}, and also either remove the previous newline, or add an explicit semicolon \';\' @ line 90, column 2.\\n   \\t{\\n    ^\\n\\n1 error\\n",\n  "exception" : "BadInputException",\n  "stacktrace" : [ "org.neo4j.server.plugin.gremlin.GremlinPlugin.executeScript(GremlinPlugin.java:88)", "java.lang.reflect.Method.invoke(Method.java:616)", "org.neo4j.server.plugins.PluginMethod.invoke(PluginMethod.java:57)", "org.neo4j.server.plugins.PluginManager.invoke(PluginManager.java:168)", "org.neo4j.server.rest.web.ExtensionService.invokeGraphDatabaseExtension(ExtensionService.java:300)", "org.neo4j.server.rest.web.ExtensionService.invokeGraphDatabaseExtension(ExtensionService.java:122)", "java.lang.reflect.Method.invoke(Method.java:616)" ]\n}')

The query within the function works on neo4j console.

[espeed]

what happens when you format it like this...?

def short() {
    return g.v(1234).outE.filter{
        return (it.pvalue > 0) || (it.correlation < 0);
    };
}

[amergin]

with a one-liner like you said it works. Furthermore, it seems that

return g.v(1234).outE.filter{

works but

return g.v(1234).outE.filter
{

does not. is this a bulbs-related issue? The point was that I should be able to able to define multi-line closures as I can in the console. I often have filter clauses that grow very long and they need to be kept readable by using line splits.

[espeed]

I'm not exactly sure what the rule is on that. Marko wrote Gremlin-Groovy so he may have a better idea of why that's true. I would post it to the Gremlin-Users group for clarification.

[amergin]

According to Marko, there Gremlin shouldn't have a problem with multi-line closures: https://groups.google.com/forum/#!topic/gremlin-users/3m_3Zl0ek6c .

Maybe Bulbs is somehow pushing the wrong kind of syntax of the script to REST API?

Care to comment?

[espeed]

Bulbs is passing the body of the script to Rexster, so Rexster is seeing this:

    return g.v(1234).outE.filter
    {
        return (it.pvalue > 0) ||
        (it.correlation < 0);
    };

Do these two versions behave differently?

    return g.v(1234).outE.filter{
        return (it.pvalue > 0) ||
        (it.correlation < 0);
    };

...and...

    return g.v(1234).outE.filter
    {
        return (it.pvalue > 0) || (it.correlation < 0);
    };

[espeed]

Closing -- assuming this has been resolved.