update readme

README.md

@@ -16,6 +16,108 @@
 pip install {{ package_name }}
 ```
 
+## Usage
+
+Setup your models.
+
+```python
+from typing import Optional
+
+from pydantic import BaseModel, Field
+
+
+class Alpha(BaseModel):
+    a: int
+
+
+class Color(BaseModel):
+    r: int
+    g: int
+    b: int
+    alpha: Alpha
+
+
+class Hair(BaseModel):
+    color: Color
+    length: int
+
+
+class Person(BaseModel):
+    name: str
+    other_name: Optional[str] = None
+    age: int
+    email: Optional[str]
+    pet: str = "dog"
+    address: str = Field("123 Main St", description="Where the person calls home.")
+    hair: Hair
+```
+
+Now create a typer command using your models.
+`expand_pydantic_args` will expand all of the typer fields
+for you.
+
+```python
+import typer
+from pydantic_typer import expand_pydantic_args
+app = typer.Typer(
+    name="pydantic_typer",
+    help="a demo app",
+)
+
+@app.command()
+@expand_pydantic_args
+def get_person(person: Person) -> Person:
+    """Get a person's information."""
+    from rich import print
+
+    print(person)
+```
+
+Get the help message.
+
+```console
+pydantic-typer get-person --help
+
+ Usage: pydantic-typer get-person [OPTIONS]
+
+ Get a person's information.
+
+╭─ Options ──────────────────────────────────────────────────────────────────────────────╮
+│ --help          Show this message and exit.                                            │
+╰────────────────────────────────────────────────────────────────────────────────────────╯
+╭─ Person ───────────────────────────────────────────────────────────────────────────────╮
+│ *  --name              TEXT     [default: None] [required]                             │
+│    --other-name        TEXT     [default: None]                                        │
+│ *  --age               INTEGER  [default: None] [required]                             │
+│    --email             TEXT     [default: None]                                        │
+│    --pet               TEXT     [default: dog]                                         │
+│    --address           TEXT     Where the person calls home. [default: 123 Main St]    │
+╰────────────────────────────────────────────────────────────────────────────────────────╯
+╭─ Person.Hair ──────────────────────────────────────────────────────────────────────────╮
+│ *  --length        INTEGER  [default: None] [required]                                 │
+╰────────────────────────────────────────────────────────────────────────────────────────╯
+╭─ Person.Hair.Color ────────────────────────────────────────────────────────────────────╮
+│ *  --r        INTEGER  [default: None] [required]                                      │
+│ *  --g        INTEGER  [default: None] [required]                                      │
+│ *  --b        INTEGER  [default: None] [required]                                      │
+╰────────────────────────────────────────────────────────────────────────────────────────╯
+╭─ Person.Hair.Color.Alpha ──────────────────────────────────────────────────────────────╮
+│ *  --a        INTEGER  [default: None] [required]                                      │
+╰────────────────────────────────────────────────────────────────────────────────────────╯
+```
+
+Calling the cli will print out a Person object.
+
+```console
+pydantic-typer get-person --name me --age 1 --r 1 --g 1 --b 1 --a 1 --length 1
+```
+
+Calling the cli while not specifying required arguments will automatically prompt for them.
+
+```console
+pydantic-typer get-person
+```
+
 ## License
 
 `{{ package_name }}` is distributed under the terms of the [MIT](https://spdx.org/licenses/MIT.html) license.