CustomGremlinGroovyPipeline#getString throws an IllegalStateException when the pipeline contains more than one element

[gdaniel]

I am not sure this restriction is actually needed. A getString method on a pipeline containing multiple elements could return a generic String built by appending the elements one after the other.

We need to be clear on this method: is it only a debugging method that helps to understand what is in the pipeline, or is it also used in the translations (for example of toString() calls in ATL)? In the later we have to be careful, because String comparisons can have unexpected behaviors if we use a generic pattern for multiple elements.

[gdaniel]

This method could be removed and translated like the following traversal:

[...]_().next().toString()

However, this translation may have some impact on the performances (need some benchmarks).