Implement syntax for specifying a specific occurrence of a node in a transformation rule

[bugdea1er]

For more accurate mutations, it will be more convenient to replace not all occurrences of a node that fits the transformation rule, but to indicate the number of a specific occurrence of the node.
For example, if I give the tree transformer the rule

Binop(#1, #2)<\"+\"> -> Binop(#1, #2)<\"-\">

and the occurence number 1, I expect for the example 5 + 4 + 5 + 4 get form the tree trasnformer 5 - 4 + 5 + 4 up to the way the nodes in the tree are numbered.

[kniazkov]

Let's clarify. Let's say our code contains two such expressions:

a = 1 + 2 + 3 + 4
b = 5 + 6 + 7 + 8

Accordingly, the syntax tree will contain branches for two such expressions. You want the rule to be applied only once for each such expression, that is, like this:

a = 1 - 2 + 3 + 4
b = 5 - 6 + 7 + 8

?

[bugdea1er]

With the proposed syntax, I would expect the tree transformer to change only one node for the entire given tree in the TreeProcessor::transform method, i.e. the rule is only applied once.

Also, I believe it would be convenient to have a method that returns the number of nodes that can be transformed by a given rule. So if I have this number in the possibleTransformations variable I could run

for (int i = 0; i < possibleTransformations; i++) {
  treeTransformer.transform(tree, i);
}

to get a list of all possible variants with the mutation applied only once to different nodes.

[pollyvolk]

Working on the implementation of this feature in API.

[kniazkov]

@rultor release, tag is 0.2.3

[rultor]

@rultor release, tag is 0.2.3

@kniazkov OK, I will release it now. Please check the progress here

[rultor]

@rultor release, tag is 0.2.3

@kniazkov Done! FYI, the full log is here (took me 8min)

[kniazkov]

@rultor release, tag is 0.2.4

[rultor]

@rultor release, tag is 0.2.4

@kniazkov OK, I will release it now. Please check the progress here

[rultor]

@rultor release, tag is 0.2.4

@kniazkov Done! FYI, the full log is here (took me 8min)