feat(python): add utilities to manage simple virtual environments (#9776)

Closes #9776

plugins/python/python.plugin.zsh

@@ -51,3 +51,36 @@ alias ipython="python -c 'import IPython; IPython.terminal.ipapp.launch_new_inst
 
 # Share local directory as a HTTP server
 alias pyserver="python -m http.server"
+
+
+## venv utilities
+
+# Activate a the python virtual environment specified.
+# If none specified, use 'venv'.
+function vrun() {
+  local name="${1:-venv}"
+  local venvpath="${name:P}"
+
+  if [[ ! -d "$venvpath" ]]; then
+    echo >&2 "Error: no such venv in current directory: $name"
+    return 1
+  fi
+
+  if [[ ! -f "${venvpath}/bin/activate" ]]; then
+    echo >&2 "Error: '${name}' is not a proper virtual environment"
+    return 1
+  fi
+
+  . "${venvpath}/bin/activate" || return $?
+  echo "Activated virtual environment ${name}"
+}
+
+# Create a new virtual environment, with default name 'venv'.
+function mkv() {
+  local name="${1:-venv}"
+  local venvpath="${name:P}"
+
+  python3 -m venv "${name}" || return
+  echo >&2 "Created venv in '${venvpath}'"
+  vrun "${name}"
+}