The behavior of $LISTBUILD on big-endian instances and little-endian instances is identical.  $LISTBUILD always builds a string of 8-bit bytes with the payload always in little-endian order.  This means $LIST data can be shared between big- and little-endian instances.  A $LIST string only uses characters between $C(0) and $C(255) since byte strings can be easily transferred over 8-bit byte network connections and can be efficiently stored in an InterSystems Globals database.  On an IRIS Unicode instance a $LIST string in memory wastes half the bytes since in-memory strings are always encoded using UTF-16 representation.  However, InterSystems IRIS will convert such data to 8-bit bytes when storing it in the database.

There are additional type codes than those described in the above article.

The %ToJSON() method of the %DynamicAbstractObject classes in the ObjectScript languageshould never generate NaN without quotation marks.  Although a %DynamicAbstractObject subclass can contain IEEE double-precision floating-point values including the special values Infinity and NaN, using %ToJSON on a %DynamicObject or a %DynamicArray that contains such special values will result in an <ILLEGAL VALUE> error signal since the JSON standard does not support such special IEEE floating-point values.  It is possible some applications have extended the JSON standard to include NaN and Infinity as numeric values without quotation marks, the ObjectScript %ToJSON method does not support such an extension.  However, @Julius Kavay did give an example how the ObjectScript ZWRITE command will display a %DynamicObject entry containing an IEEE NaN value.

I am going to assume that local variable 'identifiers' contains an oref referencing either the %DynamicArray or the %DynamicObject class.  If the 'identifiers' value is an oref that references some other class then ignore everything else in this reply.

Let us assume 'identifiers' refers to a %DynamicArray object (although a reference to a %DynamicObject would involve a similar discussion.)  Each entry in the %DynamicArray is a JSON value.  Those entries have one the following types:  "null", "boolean", "number", "oref", "object", "array" or "string".  One these type strings will be returned in variable 'type' specifying which JSON value was converted to an ObjectScript value that was returned in argument variable 'value'.  The 'type' "array" means the returned 'value' is a nested %DynamicArray reference; the 'type' 'object' means the returned 'value' is a nested %DynamicObject reference; and the 'type' "oref" means the returned 'value' is some other ObjectScript class object reference.  All other 'type' string values will mean that 'value' does not contain an oref.

The statement 'set type = value.%Get("type") is only legal in ObjectScript when 'type' contains the "array", "object" or "oref" type strings.  All other type strings will cause 'value.%Get("type") to signal an <INVALID OREF> error.  Most likely you want 'value' to be a reference to a nested %DynamicObject containing a JSON entry using the key name "type".

[[ If 'value' contains the "array" type reference then 'value.%Get(arg)' would expect 'arg' to be a number rather than a string.  If 'value' contains an "oref" type reference then 'value' would be a different ObjectScript oref which must reference a class object containing a method named '%Get'. And other types for the 'value' argument would signal <INVALID OREF> since the 'value.%Get("type")' syntax requires 'value' to an oref and the other 'type' possibilities are not oref values. ]]

The other statement 'set text = type.%Get("text")' will always signal <INVALID OREF> since %GetNext always returns a string value in the 'type' variable passed as the third argument.

So, let's assume 'identifiers' contains a JSON array where every entry in the array is a JSON object containing information about an identifier.  In this case you would know the type of each array element so you could iterate calling %GetNext(.key,.value), although if you did call %GetNext(.key,.value,.type) then immediately after the %GetNext call you could test for a data error with:
    if type'="object" { do $$$ERROR($$$GeneralError,"Invalid identifier object") }

You could then look at 'value."type"' and 'value."text"' to  get the 'type' and textual name from the JSON object describing an identifier.  [[ You do not need the %Get method when you are using a string literal as the key name of a %DynamicObject entry. Using 'value.%Get(key)' is only needed when 'key' is a run-time key name expression. ]]

I seriously doubt it is a %Regex issue.  The ? appears when some interface is converting characters to one of the many 8-bit character set codes and the source character code has a character that is not in the destination character code.  This can happen to about 2**20 characters of Unicode when they are converted to any 8-bit code.  It can also happen when converting 8-bit to a different 8-bit code.

Your terminal emulator and the IRIS terminal device can both do such conversions.  A IRIS file device can also do such conversions.  Different platforms can use different default conversions which explains why some different people cannot reproduce the results of other people.

You might be having problems with some of the unusual syntax of ObjectScript.

Like other languages created in the 1960s (E.g., FORTRAN IV and PL/I), ObjectScript does not have any reserved words.  The word 'if' can be a command if it appears where a command is specified; it can be local variable if it appears where an expression value is expected; it can sometimes be a global variable or program name if it appears after '^';  it can be a function name if it appears after '$$';  it can be a macro name if it appears after '$$$';  it be a routine or procedure name if it appears after the 'do' command; if can sometimes be a method or a property name if it appears after '.'; etc.

Your macros
    #define TestIf(%arr)    if %arr>0 QUIT 5          ;; legacy IF command
    #define TestIf(%arr)    if (%arr>0) {QUIT 5}     ;; more modern IF command
looks as if TestIf should be expanded where a command is expected so that it conditionally executes the command 'QUIT 5' which would exit the current function with a return value of 5.

However, your macro placement
    set a = $$$TestIf(3)
looks like $$$TestIf is going to be an expression containing a value for the right side of an assignment (a SET command).  It expands as
    set a = if 3 < 0 QUIT 5
which is a syntactically correct assignment of 'a' assigned the value of the variable 'if'  and that 'set' command is followed by a command named '3' which is bad syntax.

Your macro
#define logDebug(%arr) $SELECT(^GlFSL("Debug")>0:Entry^HS.Local.VA.Util.Log(%arr,,"D"),:QUIT)
looks like a macro  containing the built-in '$select' function and the macro should expand into conditional expression (as opposed to a macro containing the command 'if' which should expand in to a conditional statement.)  The first $select argument ^GlFSL("Debug")>0:Entry^HS.Local.VA.Util.Log(%arr,,"D") evaluates ^GlFSL("Debug")>0 and it that comparison is true, the $select evaluates Entry^HS.Local.VA.Util.Log(%arr,,"D") as the final value of the $select expression.  If the selector of the first argument is false then $select goes on the second argument ,:QUIT.  This has the syntax for the default value of a argument of the built-in $case function rather than be correct syntax for a $select argument.  For a $select you would write 1:QUIT which would return the value of the QUIT variable.  However,  I suspect you might have wanted a QUIT command which would terminated the current routine/procedure.  In that case you should write  the conditional commands
    if ^GlFSL("Debug")>0 then { set temp=Entry^HS.Local.VA.Util.Log(%arr,,"D")} else {QUIT}
if you do not execute the QUIT command then you can continue executing the next command line using the conditionally set 'temp' variable.

The zero date for the ObjectScript built-in $HOROLOG variable (aka $H) is 12/31/1840 so the date, 01/06,1841, you are seeing is date number 0 plus 7 days.  Now the $H day number in your Error Details, 67407,  is 07/21/2025 (i.e., today) and the $H time number (67118 seconds) is 06:38:38PM local time.

It looks like <INTERRUPT> was signaled while %ETN was generating the error log.  The <INTERRUPT> signal usually means someone typed control-C on the terminal.  The control-C may have interrupted %ETN before it had dumped all the date/time information of the original error.  The $H string in your Error Details, "67407,67118" is probably the date/time when the control-C was typed.

Your error message says the %DynamicArray class does not have a %GetAt method.  It has never had such a method although back in Caché 2016.1 there was an experimental array class that had a $getAt method.

You might try replacing all your .%GetAt(0) method calls with .%Get(0) method calls.

The default 'mindate' value for the $ZDATE(hdate,dformat,monthlist,yearopt,startwin,endwin,mindate,maxdate,erropt,localeopt)
system function call is 0, which represents 1840-12-31.  However, you can supply your own 'mindate' argument with negative values down -672045 which does date conversions more distantly into the past.

USER>zwrite $zdate(-672045,3,,,,,-672045)  
"0001-01-01"

which is Gregorian date January 1st in the year 0001 CE.  (That is the first day, in the first month in the first year of the first century.)  I should note that the Gregorian calendar was not in use back in the year 0001 CE but I don't think IRIS has support for Julius Caesar's calendar.  Passing a 'mindate' argument value more negative than -672045 will get you an <ILLEGAL VALUE> signal from $ZDATE() because there is some debate about whether the previous year is 0000 CE, -0001 CE or +0001 BCE.

$ZT is the abbreviation for the $ZTRAP system variable.  You learn more about it at https://docs.intersystems.com/iris20251/csp/docbook/Doc.View.cls?KEY=RC… 

Setting SET $ZTRAP="^%ETSDK" will call a routine name  ^%ETSDK but I have no idea what the routine is.  Maybe it is a special Error Trap routine used at your site.

Executing
    SET $ZTRAP="^%ETN"
in an ObjectScript routine will setup the ^%ETN utility routine as an error trap routine which will catch an error signal and then dump the process state into the namespace before terminating the process.  Later, executing the DO ^%ERN utility will allow you to examine the various error trap dumps in a namespace.

If you are doing a moderate amount of computing between database access then there is no question that Python is faster then ObjectScript.  If you are doing heavy computing then a call out to C++ or C would be faster than both ObjectScript and Python.

But if you doing lots of database accesses with only simple string compares and string computations between each access then ObjectScript will usually be fastest because it is so close to the Globals engine that is doing all the accesses.

Generally, manipulation of strings in ObjectScript is reasonably good.  Parsing of JSON and XML is OK if you are using functions built into ObjectScript to do the parsing.  But if you are doing character-by-character parsing of complex data structures that are not supported by ObjectScript built-ins then it might be best to call out of ObjectScript to do that parsing.

Interestingly, for small examples, L<30, the first example is slower because it does both a $LISTBUILD plus a concatenation while the others just call a $LIST/$LISTUPDATE built-in.  But for large examples, L>1000, the first example can win by at least one order of magnitude because the other examples include execution steps that take O(L**2) time.

Is the file you are editing in IRISLIB or some other Read-Only database?  If so, use the System Management Portal (SMP) to turn off the database Read-Only option.

I am not sure exactly what you want to do.  Is check1 just an ordinary string, or might it sometimes be a string that starts with a number (like a %Status variable)?

The unary plus operator (+) turns a string operand into a number.  If the string starts with the syntax of a number then +string returns that number and ignores characters in the string following the numeric syntax.  If the string does not start with a number (this includes the empty string) then +string returns 0.  It is possible for +string to signal <MAXNUMBER> if the characters at the beginning of string are too large for conversion to the computational numbers supported by ObjectScript.

You could try
  ret:+check1 check1
which would return check1 only if it were a non-empty string that starts with a non-zero number.

If you want to return a string value that could be tested as a boolean that you have to append "1" to the front of the string if +string=0 is true.

The Class Reference pages for IRIS, available in any IRIS installation, describe all the classes installed in the installation.  The Class Reference for the %Regex.Matcher class documents that the %Regex.Matcher class comes from the International Components for Unicode (ICU). The ICU maintains web pages at https://icu.unicode.org .  The class reference documentation also contains the following statement for ICU documentation specific to the IRIS %Regex:

{quote}The definition and features of the ICU regular expression package can be found in https://unicode-org.github.io/icu/userguide/strings/regexp.html .{quote}

Additional documentation on the Unicode Regex package specific to how it interacts with the Unicode character set can be found at https://www.unicode.org/reports/tr18/ .

A quick comment on performance.  A TRY ... CATCH is very efficient at run time if no exception occurs.  The only extra code that is executed is a jump at the at end of the TRY block to go around the CATCH block.  However, TRY ... CATCH is slower than using the %ZTRAP when an execption does occur.  At compile time TRY ... CATCH blocks build tables that include program counters that describe which object code locations are in each TRY block and where the corresponding CATCH block begins.  When an error is signaled (or THROWn) at run time, it is necessary to scan the frame stack searching the compile-time generated TRY ... CATCH tables to find the CATCH location to go to after popping the intermediate stack frames.  If there are no TRY ... CATCH blocks involved then it is usually faster to just jump to the most recent setting of the $ZTRAP variable.

When exceptions are "exceptional"  then TRY ... CATCH is most efficient since it avoids pushing $ZTRAP value in preparation for handling an exception and it also avoids popping the $ZTRAP value when the exception does not occur.  If exceptions are part of a usual, successful, and often executed code path then it might be better to use $ZTRAP to catch those frequently executed signals.

The %DynamicAbstractObject (%DAO) subclasses, including the %DynamicArray and %DynamicObject classes, provide the best way to read/send JSON representation into/out-of IRIS databases.

The %FromJSON method can create a tree of %DAO objects from external JSON representation.  Then elements of %DAO data can be read or accessed using ObjectScript property syntax and using methods like %Get and %GetIterator.

Data inside an IRIS database can be used to build a tree of %DAO objects by using the ObjectScript JSON constructor syntax, property assignment statements and using methods like %Set and %Push.  If all you do is store values into previously undefined elements of a %DAO object then the performance is usually quite good.  Then that %DAO tree can be turned into JSON representation using the %ToJSON method.

It is not recommended that data in a tree of %DAO objects be extensively and repetitively modified/updated by the %Set method or by other ways that can modify data in a %DAO.  This is especially true if you are repetitively changing the size of data elements.  In such cases, the data in %DAO objects should be extracted and converted to some other optimized database structure.  Often this can be Relational DataBase access if a mix of rectangular arrays provides the desirable access.  It can be a %Stream if sequential access is needed.  If a number of data elements are to be searched then columnar vectors can be used.  IRIS can supply all these other access methods by layering them on top of ObjectScript multi-dimensional arrays.  The IRIS multi-dimensional arrays (both global and local) provide the best tradeoffs across a large variety of differently ordered read/write/update/modification operations.

If you have data in a %DAO tree and you need to make small or infrequent modifications of the data then it is acceptable to leave it in %DAO representation.  You can also make repetitive reads of %DAO data without needing to convert to some other representation.  But otherwise, %DAO objects are best limited to moving data into and out-of JSON representation.