Infrastructure Software

PlSqlCustom3:

( [node^) function_call

| [node^) datetime_literal

| [node^) function_expression

) & ?node = 'TO_DATE'

& ([arg) expr

| [arg) string_literal

| [arg) pls_expr )

& node^ < arg

& [arg+1) ')'

& [arg-1) '('

;

To work out a problem like this it is better to start with expanded parse tree in the structure panel

Witness the parse tree branches of interest highlighted in orange. Apparently, the parser hasn't been consistent, and in all three TO_DATE calls has been recognized differently. This is why we have to use disjunction. Our first query attempt then is:

AllFunctionCalls:

( [node) function_call

| [node) datetime_literal

| [node) function_expression

) ;

Next, we want only TO_DATE calls which, and the function call name is the child of the node that we just have identified. At this point we could have introduced another attribute, but I have chosen to reidentify the node with TO_DATE, and make the parent to be a function call:

AllToDateCalls:

( [node^) function_call

| [node^) datetime_literal

| [node^) function_expression

) & ?node = 'TO_DATE'

;

Next, we have to introduce the second attribute -- arg, and, again, the grammar payload is different in 3 cases. More important, how to connect these two attributes, the node and the arg? It is ancestor-descendant relation, more specifically the closest ancestor-descendant. It is described at page 12 of

https://vadimtropashko.files.wordpress.com/2019/05/arbori-1.pdf

Actually, since we renamed the node to be the function call name only, it is the parent -- node^ -- which is the ancestor of the arg.

The final condition is that a single argument of the TO_DATE function call would have the open and closed parenthesis as sibling parse tree nodes. The result: