The purpose of this change is to share this trait with other crates, such as the forth-coming "semiring" crate that will be responsible for handling some simple semiring operations as well as the querying, in my plans.
Previously some incorrect forest nodes will be used for planting new nodes. I cannot fix the root cause of their presence in the chain-rule machine. But I can ignore them when they are encountered. Of course I would like to really prevent them from existing, but still cannot figure out how.
Not bug deals but adjustments of details.
* chain/src/item/default/splone.rs: A function for finding the node to plant used to ignore the condition that the children should match. Now this is fixed.
* chain/src/item/mod.rs: Some function and enum are needed across crates.
Some bugs are fixed: 1. If a non-terminal expansion can be reduced immediately, previously an extra node would be created that had no parents. Now this strange behaviour is corrected. 2. When performing reductions, a leaf non-terminal node would previously be regarded as completed. Now we will first try to complete that node, and then determine if the completion is successful, and finally determine the completedness according to the result. Of course some more tests are still pending, before I can confirm that no more bugs lurk around.
* chain/src/item/default/printer.lldb: * chain/src/item/default/printer.py: These are for experimenting with debugger supports.
* chain/src/item/default/mod.rs: * graph/src/labelled/binary.rs: * graph/src/labelled/double.rs: * graph/src/lib.rs: If we set the option "ordering" to be "out" in the declaration of nodes at the beginning, then GraphViz will not change the order of children out of nodes. This is much better looking in my opinion. * INSTALL: make insists in changing this file, so let it be.
This bumping of version is insignificant. I just find it notable that I seem to finally obtain a version without trivial bugs. Hooray!
* chain/src/item/genins.rs: The absolute path is too long and unnecessary.