Add support for version flag in Param class

Author: ncoop57

fastcore/script.py

@@ -39,16 +39,20 @@ def clean_type_str(x:str):
 class Param:
     "A parameter in a function used in `anno_parser` or `call_parse`"
     def __init__(self, help="", type=None, opt=True, action=None, nargs=None, const=None,
-                 choices=None, required=None, default=None):
-        if type in (store_true,bool):  type,action,default=None,'store_true' ,False
+                 choices=None, required=None, default=None, version=None):
+        if type in (store_true,bool):  type,action,default=None,'store_true',False
         if type==store_false: type,action,default=None,'store_false',True
         if type and isinstance(type,typing.Type) and issubclass(type,enum.Enum) and not choices: choices=list(type)
         help = help or ""
         store_attr()
 
     def set_default(self, d):
+        if self.action == "version":
+            if d != inspect.Parameter.empty: self.version = d
+            self.opt = True
+            return
         if self.default is None:
-            if d==inspect.Parameter.empty: self.opt = False
+            if d == inspect.Parameter.empty: self.opt = False
             else: self.default = d
         if self.default is not None:
             self.help += f" (default: {self.default})"

nbs/08_script.ipynb

@@ -246,16 +246,20 @@
     "class Param:\n",
     "    \"A parameter in a function used in `anno_parser` or `call_parse`\"\n",
     "    def __init__(self, help=\"\", type=None, opt=True, action=None, nargs=None, const=None,\n",
-    "                 choices=None, required=None, default=None):\n",
-    "        if type in (store_true,bool):  type,action,default=None,'store_true' ,False\n",
+    "                 choices=None, required=None, default=None, version=None):\n",
+    "        if type in (store_true,bool):  type,action,default=None,'store_true',False\n",
     "        if type==store_false: type,action,default=None,'store_false',True\n",
     "        if type and isinstance(type,typing.Type) and issubclass(type,enum.Enum) and not choices: choices=list(type)\n",
     "        help = help or \"\"\n",
     "        store_attr()\n",
     "\n",
     "    def set_default(self, d):\n",
+    "        if self.action == \"version\":\n",
+    "            if d != inspect.Parameter.empty: self.version = d\n",
+    "            self.opt = True\n",
+    "            return\n",
     "        if self.default is None:\n",
-    "            if d==inspect.Parameter.empty: self.opt = False\n",
+    "            if d == inspect.Parameter.empty: self.opt = False\n",
     "            else: self.default = d\n",
     "        if self.default is not None:\n",
     "            self.help += f\" (default: {self.default})\"\n",
@@ -288,7 +292,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "Each parameter in your function should have an annotation `Param(...)`. You can pass the following when calling `Param`: `help`,`type`,`opt`,`action`,`nargs`,`const`,`choices`,`required` (i.e. it takes the same parameters as `argparse.ArgumentParser.add_argument`, plus `opt`). Except for `opt`, all of these are just passed directly to `argparse`, so you have all the power of that module at your disposal. Generally you'll want to pass at least `help` (since this is provided as the help string for that parameter) and `type` (to ensure that you get the type of data you expect).\n",
+    "Each parameter in your function should have an annotation `Param(...)`. You can pass the following when calling `Param`: `help`,`type`,`opt`,`action`,`nargs`,`const`,`choices`,`required`, `version` (i.e. it takes the same parameters as `argparse.ArgumentParser.add_argument`, plus `opt`). Except for `opt`, all of these are just passed directly to `argparse`, so you have all the power of that module at your disposal. Generally you'll want to pass at least `help` (since this is provided as the help string for that parameter) and `type` (to ensure that you get the type of data you expect).\n",
     "\n",
     "`opt` is a bool that defines whether a param is optional or required (positional) - but you'll generally not need to set this manually, because fastcore.script will set it for you automatically based on *default* values. You should provide a default (after the `=`) for any *optional* parameters. If you don't provide a default for a parameter, then it will be a *positional* parameter.\n",
     "\n",
@@ -398,16 +402,17 @@
      "name": "stdout",
      "output_type": "stream",
      "text": [
-      "usage: progname [-h] [--b B] [--c {aa,bb,cc}] required a\n",
+      "usage: progname [-h] [--v] [--b B] [--c {aa,bb,cc}] required a\n",
       "\n",
       "my docs\n",
       "\n",
       "positional arguments:\n",
       "  required        Required param\n",
       "  a               param 1\n",
       "\n",
-      "optional arguments:\n",
+      "options:\n",
       "  -h, --help      show this help message and exit\n",
+      "  --v             Print version\n",
       "  --b B           param 2 (default: test)\n",
       "  --c {aa,bb,cc}  param 3 (default: aa)\n"
      ]
@@ -417,6 +422,7 @@
     "_en = str_enum('_en', 'aa','bb','cc')\n",
     "def f(required:Param(\"Required param\", int),\n",
     "      a:Param(\"param 1\", bool_arg),\n",
+    "      v:Param(\"Print version\", action='version', version='%(prog)s 2.0.0'),\n",
     "      b:Param(\"param 2\", str)=\"test\",\n",
     "      c:Param(\"param 3\", _en)=_en.aa):\n",
     "    \"my docs\"\n",
@@ -426,6 +432,77 @@
     "p.print_help()"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "We can also check the version and help flaggs are working (you can ignore the error message below, this is expected behavior)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "progname 2.0.0\n"
+     ]
+    },
+    {
+     "ename": "SystemExit",
+     "evalue": "0",
+     "output_type": "error",
+     "traceback": [
+      "An exception has occurred, use %tb to see the full traceback.\n",
+      "\u001b[0;31mSystemExit\u001b[0m\u001b[0;31m:\u001b[0m 0\n"
+     ]
+    }
+   ],
+   "source": [
+    "p.parse_args(['--v'])"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "usage: progname [-h] [--v] [--b B] [--c {aa,bb,cc}] required a\n",
+      "\n",
+      "my docs\n",
+      "\n",
+      "positional arguments:\n",
+      "  required        Required param\n",
+      "  a               param 1\n",
+      "\n",
+      "options:\n",
+      "  -h, --help      show this help message and exit\n",
+      "  --v             Print version\n",
+      "  --b B           param 2 (default: test)\n",
+      "  --c {aa,bb,cc}  param 3 (default: aa)\n"
+     ]
+    },
+    {
+     "ename": "SystemExit",
+     "evalue": "0",
+     "output_type": "error",
+     "traceback": [
+      "An exception has occurred, use %tb to see the full traceback.\n",
+      "\u001b[0;31mSystemExit\u001b[0m\u001b[0;31m:\u001b[0m 0\n"
+     ]
+    }
+   ],
+   "source": [
+    "p.parse_args(['-h'])"
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},
@@ -450,7 +527,7 @@
       "  required        Required param\n",
       "  a               param 1\n",
       "\n",
-      "optional arguments:\n",
+      "options:\n",
       "  -h, --help      show this help message and exit\n",
       "  --b B           param 2 (default: test)\n",
       "  --c {aa,bb,cc}  param 3 (default: aa)\n"