Greek and English in lstlisting

Question

I'm trying to create an lstlisting that contains both english and greek letters.

I have set this style.

\lstset{
      basicstyle=\normalsize\selectlanguage{english}\ttfamily,  % COURIER NEW?
    frame=tb, % draw a frame at the top and bottom of the code block
    tabsize=4, % tab space width
    showstringspaces=false, % don't mark spaces in strings
    numbers=left, % display line numbers on the left
    commentstyle=\color{black}, % comment color
    keywordstyle=\color{black}, % keyword color
    stringstyle=\color{black} % string color
}

and I want to include this code inside the lstlisting. As you can see there is greek text: 'Σύνθετη Αναζήτηση'. However when i run the pdfLatex compiler, it is rendered in latin character.

\begin{lstlisting}
<?php

function custom_toolbar_link($wp_admin_bar) {
    $args = array(
        'id' => 'advanced_search',
        'title' => 'Σύνθετη Αναζήτηση',
        'href' => 'admin.php?page=advanced-search',

        'meta' => array(
            'class' => 'advanced_search',
            'title' => 'advanced search'
        )
    );
    $wp_admin_bar->add_node($args);
}
add_action('admin_bar_menu', 'custom_toolbar_link', 10);
\end{lstlisting}

Can you help me?

*** A full minimal example of the text:

\documentclass[11pt,a4paper,fleqn]{article}
\usepackage{listings}
\usepackage{dirtree}
\usepackage{indentfirst}
\usepackage[greek,english]{babel}
\usepackage[iso-8859-7]{inputenc}
\usepackage{chicago}
\usepackage[section]{placeins}

\lstset{
      basicstyle=\normalsize\selectlanguage{english}\ttfamily,  % COURIER NEW?
    frame=tb, % draw a frame at the top and bottom of the code block
    tabsize=4, % tab space width
    showstringspaces=false, % don't mark spaces in strings
    numbers=left, % display line numbers on the left
    commentstyle=\color{black}, % comment color
    keywordstyle=\color{black}, % keyword color
    stringstyle=\color{black} % string color
}

% This concludes the preamble
\begin{document}

\begin{lstlisting}[label=some-code,caption=Some Code]
<?php
function custom_toolbar_link($wp_admin_bar) {
    $args = array(
        'id' => 'advanced_search',
        'title' => 'Σύνθετη Αναζήτηση',
        'href' => 'admin.php?page=advanced-search',
        'meta' => array(
            'class' => 'advanced_search',
            'title' => 'advanced search'
        )
    );
    $wp_admin_bar->add_node($args);
}
add_action('admin_bar_menu', 'custom_toolbar_link', 10);
\end{lstlisting}

\end{document}

Answer 1

If you can use LuaLaTeX or XeLaTeX, you can load any monospaced Unicode font through fontspec that contains Greek, such as New Computer Modern Mono or Libertinus Mono.

\documentclass[11pt,a4paper,fleqn]{article}
\usepackage[english]{babel}
\usepackage{newcomputermodern}
\usepackage{listings}

\babelprovide[import]{greek}

\lstset{
    basicstyle=\normalsize\selectlanguage{english}\ttfamily,  % COURIER NEW?
    frame=tb, % draw a frame at the top and bottom of the code block
    tabsize=4, % tab space width
    showstringspaces=false, % don't mark spaces in strings
    numbers=left, % display line numbers on the left
    commentstyle=\color{black}, % comment color
    keywordstyle=\color{black}, % keyword color
    stringstyle=\color{black} % string color
}

% This concludes the preamble
\begin{document}

\begin{lstlisting}[label=some-code,caption=Some Code]
<?php
function custom_toolbar_link($wp_admin_bar) {
    $args = array(
        'id' => 'advanced_search',
        'title' => 'Σύνθετη Αναζήτηση',
        'href' => 'admin.php?page=advanced-search',
        'meta' => array(
            'class' => 'advanced_search',
            'title' => 'advanced search'
        )
    );
    $wp_admin_bar->add_node($args);
}
add_action('admin_bar_menu', 'custom_toolbar_link', 10);
\end{lstlisting}

\end{document}

You indicated in a comment that you wanted to use Courier New. That would not be my recommendation, but if you do, you can add the lines

\usepackage{fontspec}

\setmonofont{Courier New}[Scale=MatchLowercase]

If you are forced to use PDFLaTeX, the listing package does not support UTF-8, but might work with ISO-8859-7. You may wish to use selinput to automatically detect the input encoding, so that a document saved as UTF-8 has a chance to compile.

\documentclass[11pt,a4paper,fleqn]{article}
\usepackage[LGR,T1]{fontenc}
\usepackage{selinput} % Auto-detect input encoding.
\usepackage{textalpha} % Enable Greek text
\usepackage[greek,english]{babel}
\usepackage{listings}

\SelectInputEncodingList{utf8, iso-8859-7}
\SelectInputMappings{ alpha=α }

\lstset{
    basicstyle=\normalsize\ttfamily,
    frame=tb, % draw a frame at the top and bottom of the code block
    tabsize=4, % tab space width
    showstringspaces=false, % don't mark spaces in strings
    numbers=left, % display line numbers on the left
    commentstyle=\color{black}, % comment color
    keywordstyle=\color{black}, % keyword color
    stringstyle=\color{black}, % string color
    extendedchars=false % listings does not support UTF-8.
}

% This concludes the preamble
\begin{document}

\begin{lstlisting}[label=some-code,caption=Some Code]
<?php
function custom_toolbar_link($wp_admin_bar) {
    $args = array(
        'id' => 'advanced_search',
        'title' => 'Σύνθετη Αναζήτηση'
        'href' => 'admin.php?page=advanced-search',
        'meta' => array(
            'class' => 'advanced_search',
            'title' => 'advanced search'
        )
    );
    $wp_admin_bar->add_node($args);
}
add_action('admin_bar_menu', 'custom_toolbar_link', 10);
\end{lstlisting}

\end{document}

Another option is to use minted.

Answer 2

You can escape to Latex. for example:

\begin{lstlisting}[label=some-code,caption=Some Code,escapeinside=;;]
<?php
function custom_toolbar_link($wp_admin_bar) {
$args = array(
'id' => 'advanced_search',
'title' => ';\selectlanguage{greek}Σύνθετη Αναζήτηση\selectlanguage{english};',
'href' => 'admin.php?page=advanced-search',
'meta' => array(
'class' => 'advanced_search',
'title' => 'advanced search'
)
);
$wp_admin_bar->add_node($args);
}
add_action('admin_bar_menu', 'custom_toolbar_link', 10);
\end{lstlisting}