Initial contribution to define Node Expressions library (#432)

* Started some early work on adding node expressions

* Progress

* Progress

* Progress on lists and if

* Progress: distinct, intersection, union, minus

* Progress: Limit and offset

* Progress: aggregations

* Update shacl12-node-expr/index.html

Co-authored-by: Ted Thibodeau Jr <[email protected]>

* Apply suggestions from code review

Co-authored-by: David Habgood <[email protected]>

* Clarifications

* Better structure, partly inspired by Andy's comment

* Apply suggestions from code review

Co-authored-by: Ted Thibodeau Jr <[email protected]>

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Co-authored-by: Ted Thibodeau Jr <[email protected]>
Co-authored-by: David Habgood <[email protected]>

Author: 3 people