main.py

from fasthtml.common import *
from dataclasses import make_dataclass, fields
import datetime
from pathlib import Path

import yaml

def create_dataclass_from_schema(schema_dict, cls_name="DynamicClass"):
    str2type = {
        "str": str,
        "int": int,
        "bool": bool,
        "float": float,
        "list": list,
        "tuple": tuple,
        "dict": dict,
        "set": set,
        "path": Path,
        "date": datetime.date,
    }
    fields = [(name, str2type[type_str]) for name, type_str in schema_dict.items()]
    cls = make_dataclass(cls_name, fields)
    return cls


def field2inp(f, value=None):
    t2t = {str: "text", int: "number", datetime.date: "date", bool: "checkbox"}

    inp = Input(
        type=t2t.get(f.type, "text"),
        value=value if f.type is not bool else None,
        id=f.name,
        required=f.type is not bool,
        checked=f.type is bool and value,
    )

    return Label(f.name.capitalize(), fr=f.name), inp

config = yaml.safe_load(Path("schema.yaml").read_text(encoding="utf-8"))

user_schema = config["user"]

User = create_dataclass_from_schema(user_schema, "User")

app, rt = fast_app()

@rt('/')
def index():
    u = User("John", 30, "1992-10-19")
    return Main(cls="container")(
        Form(action="#")(
            *[
                field2inp(f, getattr(u, f.name)) # or if you need an empty form, just field2inp(f)
                for f in fields(User)
            ],
            Button("Submit", type="submit")
        )
    )

serve()

schema.yaml

user:
  name: str
  age: int
  birthday: date