move json schema to directory/package (#407)

* move json schema to directory/package

* added jsonschema to README

jsonschema/json.go

@@ -0,0 +1,35 @@
+// Package jsonschema provides very simple functionality for representing a JSON schema as a
+// (nested) struct. This struct can be used with the chat completion "function call" feature.
+// For more complicated schemas, it is recommended to use a dedicated JSON schema library
+// and/or pass in the schema in []byte format.
+package jsonschema
+
+type DataType string
+
+const (
+	Object  DataType = "object"
+	Number  DataType = "number"
+	Integer DataType = "integer"
+	String  DataType = "string"
+	Array   DataType = "array"
+	Null    DataType = "null"
+	Boolean DataType = "boolean"
+)
+
+// Definition is a struct for describing a JSON Schema.
+// It is fairly limited and you may have better luck using a third-party library.
+type Definition struct {
+	// Type specifies the data type of the schema.
+	Type DataType `json:"type,omitempty"`
+	// Description is the description of the schema.
+	Description string `json:"description,omitempty"`
+	// Enum is used to restrict a value to a fixed set of values. It must be an array with at least
+	// one element, where each element is unique. You will probably only use this with strings.
+	Enum []string `json:"enum,omitempty"`
+	// Properties describes the properties of an object, if the schema type is Object.
+	Properties map[string]Definition `json:"properties,omitempty"`
+	// Required specifies which properties are required, if the schema type is Object.
+	Required []string `json:"required,omitempty"`
+	// Items specifies which data type an array contains, if the schema type is Array.
+	Items *Definition `json:"items,omitempty"`
+}