Add documentation for using as library #3130

Signed-off-by: Chin Yeung Li <tli@nexb.com>

Author: chinyeungli

docs/source/getting-started/install.rst

@@ -423,6 +423,10 @@ For more information on Python virtualenv, visit this
     no default dependencies on pre-built binaries. This may come handy for some
     special use cases such as packaging for a Linux or FreeBSD distro.
 
+.. NOTE::
+
+  Refer :ref:`run_as_library` for usage samples.
+
 
 To uninstall, run::
 

docs/source/how-to-guides/index.rst

@@ -14,5 +14,6 @@
    add_new_license
    add_new_license_detection_rule
    install_new_license_plugin
+   run_as_library
    generate_attribution
    how_to_add_a_post_scan_plugin

docs/source/how-to-guides/run_as_library.rst

@@ -0,0 +1,39 @@
+.. _run_as_library:
+
+Run as Library
+==============
+
+If you’ve installed ScanCode-Toolkit as a library (:ref:`pip_install`), you
+can directly import it into your Python scripts.
+
+ScanCode-Toolkit offers a wide range of callable functions. Each function
+includes in-code documentation. Users can refer to it to understand the
+purpose of each function, then import and use the ones they need.
+
+While listing them all isn't feasible, here are a few sample use cases.
+
+To Run a Scan
+-------------
+
+::
+
+    from scancode.cli import run_scan
+
+
+See https://github.com/aboutcode-org/scancode-toolkit/blob/develop/src/scancode/cli.py#L535
+
+
+Get YAML Safe Text
+------------------
+
+::
+
+    from licensedcode.models import get_yaml_safe_text
+
+
+See https://github.com/aboutcode-org/scancode-toolkit/blob/develop/src/licensedcode/models.py#L777
+
+
+.. NOTE::
+
+    For more sample usages, refer https://github.com/nexB/scancode.io/blob/main/scanpipe/pipes/scancode.py