mochi - v2.0.0

mochi/args

Typed accessor for GraphQL field arguments.

Resolvers receive arguments as Args, an opaque wrapper around a Dict(String, Dynamic). Use the get_* family to read fields with type checking; to_dict is a back-compat escape hatch.

Types

ArgError

</>

Why an argument lookup failed. Resolvers normally translate this into a mochi/error.GraphQLError at the boundary — kept structural here so mochi/args doesn’t have to depend on the error module (which would cycle through types and schema).

pub type ArgError {
  Missing(key: String)
  WrongType(key: String, expected: String)
  InvalidInput(key: String)
}

Constructors 

  • Missing(key: String)
  • WrongType(key: String, expected: String)
  • InvalidInput(key: String)

Args

opaque </> 
pub opaque type Args

Values

decode_input

</> 
pub fn decode_input(
  a: Args,
  key: String,
  decoder: decode.Decoder(b),
) -> Result(b, ArgError)

error_message

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pub fn error_message(err: ArgError) -> String

Render an ArgError as the same kind of message the legacy query.get_* family produced, so downstream error reporting doesn’t change.

from_dict

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pub fn from_dict(d: dict.Dict(String, dynamic.Dynamic)) -> Args

Wrap a raw dict as Args. The executor calls this at the resolver boundary; user code rarely needs it directly.

get_bool

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pub fn get_bool(a: Args, key: String) -> Result(Bool, ArgError)

get_float

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pub fn get_float(a: Args, key: String) -> Result(Float, ArgError)

get_id

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pub fn get_id(a: Args, key: String) -> Result(String, ArgError)

get_int

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pub fn get_int(a: Args, key: String) -> Result(Int, ArgError)

get_int_list

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pub fn get_int_list(
  a: Args,
  key: String,
) -> Result(List(Int), ArgError)

get_optional_bool

</> 
pub fn get_optional_bool(
  a: Args,
  key: String,
) -> option.Option(Bool)

get_optional_float

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pub fn get_optional_float(
  a: Args,
  key: String,
) -> option.Option(Float)

get_optional_int

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pub fn get_optional_int(
  a: Args,
  key: String,
) -> option.Option(Int)

get_optional_string

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pub fn get_optional_string(
  a: Args,
  key: String,
) -> option.Option(String)

get_string

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pub fn get_string(
  a: Args,
  key: String,
) -> Result(String, ArgError)

get_string_list

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pub fn get_string_list(
  a: Args,
  key: String,
) -> Result(List(String), ArgError)

to_dict

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pub fn to_dict(a: Args) -> dict.Dict(String, dynamic.Dynamic)

Unwrap to the underlying dict — for code bridging to APIs that still take Dict(String, Dynamic). Avoid in new code.

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