DECLARE (*ambassert)() TYPE NUMBER

FUNCTION amb_recurse$(text$[], nr, total, result$)

    LOCAL ctr
    LOCAL str$, test$

    FOR ctr = 1 TO AMOUNT(text$[nr])
        str$ = APPEND$(result$, 0, TOKEN$(text$[nr], ctr))
        IF nr = total-1 THEN
            IF ambassert(str$) THEN RETURN str$
        ELSE
            test$ = amb_recurse$(text$, nr+1, total, str$)
            IF AMOUNT(test$) = total THEN RETURN test$
        ENDIF
    NEXT

    RETURN ""

ENDFUNC

FUNCTION ambsel$(VAR data$ SIZE dim)

    RETURN IIF$(dim < 2, "ambsel$ needs more than 1 argument", amb_recurse$(data$, 0, dim, ""))

ENDFUNC

FUNCTION this_is_some_constraint(var$)

    DOTIMES AMOUNT(var$)-1
        IF RIGHT$(TOKEN$(var$, _), 1) != LEFT$(TOKEN$(var$, _+1), 1) THEN RETURN FALSE
    DONE

    RETURN TRUE

ENDFUNC

' AMBASSERT: pointing to a constraint function
ambassert = this_is_some_constraint

' AMBSEL$: generate result from arguments in delimited string format
PRINT ambsel$("the that a", "frog elephant thing", "walked treaded grows", "slowly quickly")