Source code for gam.ast.event

from typing import Literal, Union, List, Optional

from pydantic import Field

from gam.ast.base_ast import ASTNode
from gam.ast.stmt import FunctionDeclaration
from gam.ast.expr import Identifier, Expression




class EventHandler(ASTNode):
    """
    Represents an event handler that responds to specific events.

    For example:
    ```
    Button(
        events=[
            EventHandler(
                event=Event(event_type='click'),
                handler_function=Identifier(name='handleClick')
            ),
            EventHandler(
                event=Event(event_type='change'),
                handler_function=Identifier(name='handleChange')
            ),
        ]
    )
    ```
    """
    name: Literal['EventHandler'] = Field(default='EventHandler')

    event_type: Literal['click', 'input', 'change', 'submit'] = Field(
        description="The type of event this handler responds to"
    )
    
    handler_function: Union[Identifier, FunctionDeclaration] = Field(
        description="The function that handles the event"
    )
    args: Optional[List[Expression]] = Field(
        default=None,
        description="The arguments to pass to the handler function. Used for rendering the event handler." \
            "Usually used in the component that support for loop. e.g. Card, DataTable, etc."
    )