added example generation

parser/example.go

@@ -0,0 +1,48 @@
+package parser
+
+import "encoding/json"
+
+// Example generates an object that is a realistic example
+// of this object.
+// Examples are read from the docs.
+// This is experimental.
+func (d *Definition) Example(o Object) (map[string]interface{}, error) {
+	obj := make(map[string]interface{})
+	for _, field := range o.Fields {
+		if field.Type.IsObject {
+			subobj, err := d.Object(field.Type.TypeName)
+			if err != nil {
+				return nil, err
+			}
+			example, err := d.Example(*subobj)
+			if err != nil {
+				return nil, err
+			}
+			obj[field.Name] = example
+			if field.Type.Multiple {
+				// turn it into an array
+				obj[field.Name] = []interface{}{obj[field.Name]}
+			}
+			continue
+		}
+		obj[field.Name] = field.Example
+		if field.Type.Multiple {
+			// turn it into an array
+			obj[field.Name] = []interface{}{obj[field.Name], obj[field.Name], obj[field.Name]}
+		}
+	}
+	return obj, nil
+}
+
+// ExampleJSON is like Example, but returns a JSON string.
+func (d *Definition) ExampleJSON(o Object) (string, error) {
+	example, err := d.Example(o)
+	if err != nil {
+		return "", err
+	}
+	exampleBytes, err := json.MarshalIndent(example, "", "\t")
+	if err != nil {
+		return "", err
+	}
+	return string(exampleBytes), nil
+}

parser/example_test.go

@@ -0,0 +1,69 @@
+package parser
+
+import (
+	"encoding/json"
+	"fmt"
+	"testing"
+
+	"github.com/matryer/is"
+)
+
+func TestObjectExample(t *testing.T) {
+	is := is.New(t)
+
+	obj1 := Object{
+		Name: "obj1",
+		Fields: []Field{
+			{
+				Name:    "Name",
+				Example: "Mat",
+			},
+			{
+				Name:    "Project",
+				Example: "Respond",
+			},
+			{
+				Name:    "SinceYear",
+				Example: 2021,
+			},
+			{
+				Name: "Favourites",
+				Type: FieldType{
+					TypeName: "obj2",
+					IsObject: true,
+				},
+			},
+		},
+	}
+	obj2 := Object{
+		Name: "obj2",
+		Fields: []Field{
+			{
+				Type:    FieldType{TypeName: "string", Multiple: true},
+				Name:    "Languages",
+				Example: "Go",
+			},
+		},
+	}
+	def := &Definition{
+		Objects: []Object{obj1, obj2},
+	}
+	example, err := def.Example(obj1)
+	is.NoErr(err)
+	is.True(example != nil)
+
+	b, err := json.MarshalIndent(example, "", "\t")
+	is.NoErr(err)
+	fmt.Println(string(b))
+
+	is.Equal(example["Name"], "Mat")
+	is.Equal(example["Project"], "Respond")
+	is.Equal(example["SinceYear"], 2021)
+	is.True(example["Favourites"] != nil)
+	favourites, ok := example["Favourites"].(map[string]interface{})
+	is.True(ok) // Favourites map[string]interface{}
+	languages, ok := favourites["Languages"].([]interface{})
+	is.True(ok) // Languages []interface{}
+	is.Equal(len(languages), 3)
+
+}