Hebrew date without day of month using polyglossia

Question

I'd like to typeset today's month and year, where "today" is determined automatically. However, I'd like to do so using polyglossia's Hebrew locale. I've tried to adapt this answer as follows:

\documentclass{article}
\usepackage{polyglossia}
\setdefaultlanguage{hebrew}
\usepackage{fontspec}
\setmainfont{Arial}
\setmonofont{Arial}
\setsansfont{Arial}
\usepackage[useregional]{datetime2}
\DTMlangsetup[he]{showdayofmonth=false}
\begin{document}
\today
\end{document}

However, this prints the day of the month (I used XeLaTeX):

Instead of the desired:

* The package datetime2-hebrew is installed in my TeX installation.

Answer 1

Multiple things are intertwining.

With the current code setup, datetime2 is ignoring the option:

Package datetime2 Warning: Region `he' has ignored 
(datetime2)                the following settings:
(datetime2)                showdayofmonth=false

and polyglossia is calculating the date via hebrewcal.sty where the output routine hard-codes the day number using a formatting command defined as:

\def\@FormatForHebrew#1#2#3{%
  \Hebrewnumeral{#1}~ב\HebrewMonthName{#2}{#3}~%
  \HebrewYearName{#3}}

To fix that, as a workaround, put the following code in the preamble, before \begin{document}:

\makeatletter
\def\@FormatForHebrew#1#2#3{%
  \HebrewMonthName{#2}{#3}~%
  \HebrewYearName{#3}}
\makeatother

so that \today produces this:

Alternatively, to restrict the redefinition to a particular instance only, use braces { } and put the code in the body of the document with the \today command, such that

\today

{
\makeatletter
\def\@FormatForHebrew#1#2#3{%
  \HebrewMonthName{#2}{#3}~%
  \HebrewYearName{#3}}
\makeatother
\today
}

\today

produces this:

MWE

\documentclass{article}
\usepackage{polyglossia}
\setdefaultlanguage{hebrew}

\setmainfont{Arial}
\setmonofont{Arial}
\setsansfont{Arial}
\usepackage[useregional]{datetime2}
\DTMlangsetup[he]{showdayofmonth=false}

%%for global change:
%\makeatletter
%\def\@FormatForHebrew#1#2#3{%
%  \HebrewMonthName{#2}{#3}~%
%  \HebrewYearName{#3}}
%\makeatother

\begin{document}
\today

{
\makeatletter
\def\@FormatForHebrew#1#2#3{%
  \HebrewMonthName{#2}{#3}~%
  \HebrewYearName{#3}}
\makeatother
\today
}

\today
\end{document}

A longer-term solution will require deeper investigation, particularly as multi-way package interactions are involved.

Answer 2

Perhaps a simpler solution.

(See also format the year)

\documentclass{article}
\usepackage{polyglossia}
\setdefaultlanguage{hebrew}
\setotherlanguage{english}

\usepackage{fontspec}
\setmainfont{Arial}
\setmonofont{Arial}
\setsansfont{Arial}
\usepackage[useregional]{datetime2}


\newcommand{\ToNoDay}{% just month and year
 \hebrewsetreg\HebrewMonthName{\hebrewmonth}{\hebrewday}~\HebrewYearName{\hebrewyear}}

\begin{document}
    
\begin{english} 
\bigskip \hfill TODAY 
\end{english}

\today
    
\begin{english} 
\bigskip    \hfill  MONTH
\end{english}   
    
\HebrewMonthName{\hebrewmonth}{\hebrewday} % It needs \today to be run earlier

\begin{english} 
    \bigskip    \hfill  YEAR
\end{english}   

\HebrewYearName{\hebrewyear} % It needs \today to be run earlier
    
\begin{english} 
\bigskip    \hfill  MONTH YEAR
\end{english}   

\ToNoDay % date without the day     

\end{document}