Check for missing dependencies before building the website (#1678)

- Add an executable permission to the file.
 - Check for dependencies before the build starts.
 - Output a list of missing dependencies.

website/build_website.sh

@@ -1,8 +1,29 @@
+#!/bin/bash
 #
 # This script generates documentation using pydoc-markdown and renders the website using Quarto.
 #
-# Usage: bash build_website.sh
+
+missing_deps=false
+
 #
+# Check for missing dependencies, report them, and exit when building the
+# website is likely to fail.
+#
+for dependency in node pydoc-markdown quarto python yarn npm
+do
+    if ! command -v "$dependency" &> /dev/null
+    then
+        echo "Command '$dependency' not found."
+        missing_deps=true
+    fi
+done
+
+if [ "$missing_deps" = true ]
+then
+    echo -e "\nSome of the dependencies are missing."
+    echo "Please install them to build the website."
+    exit 1
+fi
 
 # Generate documentation using pydoc-markdown
 pydoc-markdown