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RESO RCP-019

ANTLR 4 implementation of the RESO RCP-019 grammar, with backwards-compatibility support for RETS 1.9 Validation Expressions.

20180506 - using the included rcp019.g4 file, the following expressions should parse:

  • Basic arithmetic
    3 + 5

  • Bracketed RETSNAMEs
    [ListPrice] > 0

  • RCP61 added support for unbracketed RETSNAMEs
    ListPrice > 0

  • To get current value of any field, just use the DICTNAME of that field
    ListPrice

  • RETS had support for the LAST keyword, which now works on all fields
    to get the old value
    LAST Status != "Sold"

  • Which is useful for field change detection
    ListPrice != LAST ListPrice

  • Function calls are also supported, as long as they don't use
    any of the RETSNAME keywords
    foo()
    foo ('bar', 'baz', 42)

  • Lists of expressions are also supported
    (ListPrice, Status, 3+5, LAST Status, (1, 2, 3))

  • Supports complex expressions with grouping
    ListPrice > 5.01 .AND. (1, 2, 3) .CONTAINS. 3 .OR. (Status .IN. ('Active', 'Pending') .AND. .USERLEVEL. != "Admin")

  • Which parses differently than
    ListPrice > 5.01 .AND. (1, 2, 3) .CONTAINS. 3 .OR. Status .IN. ('Active', 'Pending') .AND. .USERLEVEL. != "Admin"

20190304 - added collection support

  • RCP-019.1 added support for collections which include LIST() and SET(). These functions take 0 or more items. Backwards compatibility with the previous list syntax of () has been preserved.
Expression Result Comments
LIST(1, 2, 2, 3) LIST(1, 2, 2, 3 Duplicate items are preserved.
SET(1, 2, 2, 3) SET(1, 2, 3) Duplicate items are removed.
  • RCP-019.1 also added support for DIFFERENCE(), INTERSECTION(), and UNION(), which are intended to produce types in the following manner:
    • Operations on homogeneous collections of LIST() or SET() should return LIST() or SET(), respectively. For example, UNION(LIST('a', 'b', 3+5), LIST(6)) should return LIST('a', 'b', 6, 8).
    • Operations on heterogenous collections of LIST() or SET(), for instance DIFFERENCE(LIST(1, 2, 3), SET(3)) should return LIST().

These special functions require at least two arguments of type LIST() or SET()

Expression Result Comments
DIFFERENCE(LIST(1, 2, 3), LIST(1, 2)) LIST(3) Collection operators require two or more LIST() or SET() arguments.
UNION(LIST(1, 2), SET(3)) LIST(1, 2, 3) Arguments of type LIST() are converted to SET().
INTERSECTION(SET(DIFFERENCE(LIST(1, 2, 3), SET(1))), SET(2)) SET(2) Since the return type of collection operators is SET() or LIST(), they can be composed.