language.md

title
Language

Abstract Syntax Tree (AST)

Hot Chocolate seems to focus solely around ObjectType, InputType et al. These types work as an interface to configure the GraphQL schema. This schema is used to parse and validate incoming requests. Under the hood, every query, mutation or subscription request is parsed into a so-called abstract syntax tree. Each node of this tree denotes a part of the incoming GraphQL query.

query Users {
  userName
  address {
    street
    nr
  }
}

graph TD;
    OperationDefinitionNode   -->  s1["SelectionSetNode"]
    s1["SelectionSetNode"]  --> id5["FieldNode (userName)"]
    s1["SelectionSetNode"]  --> id1["FieldNode (address)"]
    id1["FieldNode (address)"] -->  s2["SelectionSetNode"]
    s2["SelectionSetNode"]  -->   id3["FieldNode (street)"]
    s2["SelectionSetNode"]  -->   id4["FieldNode (nr)"]

---

Syntax Node

Every node in a syntax tree implements ISyntaxNode.

💡 The ToString method of a syntax node prints the corresponding GraphQL syntax.

This interface defines the NodeKind of the node.

Node Kinds:

Name	Description (Spec Link)	Context	Example
Name	All names. e.g. Field, Argument ...	Both	foo
NamedType	Denotes a reference to a type	Both	Foo
ListType	Definition of a list	Both	[Foo]
NonNullType	Definition of type that cannot be null	Both	Foo!
Argument	Representation of an argument. Has a Name and a Value	Both	foo: "bar"
Directive	Denotes a directive	Query	@foo
Document	Describes a complete file or request a GraphQL service operates on.	Query (out)
OperationDefinition	Describes a graphql operation like query mutation or subscription	Query (out)	query Foo {}
VariableDefinition	The variables defined by an operation	Query (out)	($foo: String)
Variable	A variable	Query (out)	$foo
SelectionSet	specifies a selection of Field, FragmentSpread or InlineFragment	Query (out)	{foo bar}
Field	Describes a field as a part of a selection set	Query (out)	foo
FragmentSpread	Denotes a spread of a FragmentDefinition	Query (out)	...f1
InlineFragment	Denotes an inline fragment	Query (out)	... on Foo { bar}
FragmentDefinition	Defines the definition of a fragment	Query (out)	fragment f1 on Foo {}
IntValue	Denotes a int value	Query (in)	1
StringValue	Denotes a string value	Query (in)	"bar"
BooleanValue	Denotes a boolean value	Query (in)	true
NullValue	Denotes a null value	Query (in)	null
EnumValue	Denotes a enum value	Query (in)	FOO
FloatValue	Denotes a Float value	Query (in)	0.2
ListValue	Denotes a List value	Query (in)	["string"]
ObjectValue	Denotes a ObjectValue value	Query (in)	{foo: "bar" }
ObjectField	Denotes a field of am input object type	Query (in)	foo: "bar"
SchemaDefinition	Definition of a schema	Schema	schema {}
OperationTypeDefinition	This defines one of the root operations Query, Mutation or Subscription on the schema-definition	Schema	query:FooQuery
ScalarTypeDefinition	Definition of a scalar	Schema	scalar JSON
ObjectTypeDefinition	Definition of an object type	Schema	type Foo{}
FieldDefinition	Definition of a field	Schema	bar:String
InputValueDefinition	Definition of a input value of an argument	Schema	x: Float
InterfaceTypeDefinition	Definition of an interface	Schema	interface NamedEntity {}
UnionTypeDefinition	Definition of an union	Schema	union Ex = Foo | Bar
EnumTypeDefinition	Definition of an enum	Schema	enum Foo {BAR}
EnumValueDefinition	Definition of an enum value	Schema	BAR
InputObjectTypeDefinition	Definition of an input type definition	Schema	input FooInput {}
SchemaExtension	Definition of a schema extension	Schema	extend schema {}
ScalarTypeExtension	Definition of a scalar extension	Schema	extend scalar Foo @bar
ObjectTypeExtension	Definition of an object type extension	Schema	extend type Foo { name}
InterfaceTypeExtension	Definition of an interface type extension	Schema	extend interface NamedEntity {}
UnionTypeExtension	Definition of an union type extension	Schema	extend union Ex = Foo{}
EnumTypeExtension	Definition of an enum type extension	Schema	extend enum foo{}
InputObjectTypeExtension	Definition of an input types	Schema	input foo {}
DirectiveDefinition	Definition of a directive	Schema	directive @foo on