Move to yaml-based configuration

This commit updates the configuration to be yaml-based and updates the
configuration to read in a yaml file.

pkg/validator/validator_test.go

@@ -0,0 +1,123 @@
+package validator
+
+import (
+	"errors"
+	"fmt"
+	"strconv"
+)
+
+func ExampleValidate() {
+	var value struct {
+		Number    int    `validate:"positive" default:"234"`
+		String    string `validate:"nonempty" default:"stuff"`
+		Recursive struct {
+			Number int    `validate:"positive" default:"45"`
+			String string `validate:"nonempty" default:"more"`
+		} `recurse:"true"`
+	}
+
+	collection := make(Collection, 2)
+	Add(collection, "positive", func(value *int, dflt string) error {
+		if *value == 0 {
+			i, err := strconv.ParseInt(dflt, 10, 64)
+			if err != nil {
+				return err
+			}
+			*value = int(i)
+			return nil
+		}
+		if *value < 0 {
+			return errors.New("not positive")
+		}
+		return nil
+	})
+	Add(collection, "nonempty", func(value *string, dflt string) error {
+		if *value == "" {
+			*value = dflt
+		}
+		if *value == "" {
+			return errors.New("empty string")
+		}
+		return nil
+	})
+
+	err := Validate(&value, collection)
+	fmt.Printf("%v\n", value)
+	fmt.Println(err)
+	// Output: {234 stuff {45 more}}
+	// <nil>
+}
+
+func ExampleValidate_fail() {
+	var value struct {
+		Number    int    `validate:"positive" default:"12"`
+		String    string `validate:"nonempty" default:"stuff"`
+		Recursive struct {
+			Number int    `validate:"positive" default:"12"`
+			String string `validate:"nonempty"`
+		} `recurse:"true"`
+	}
+
+	collection := make(Collection, 2)
+	Add(collection, "positive", func(value *int, dflt string) error {
+		if *value == 0 {
+			i, err := strconv.ParseInt(dflt, 10, 64)
+			if err != nil {
+				return err
+			}
+			*value = int(i)
+			return nil
+		}
+		if *value < 0 {
+			return errors.New("not positive")
+		}
+		return nil
+	})
+	Add(collection, "nonempty", func(value *string, dflt string) error {
+		if *value == "" {
+			*value = dflt
+		}
+		if *value == "" {
+			return errors.New("empty string")
+		}
+		return nil
+	})
+
+	err := Validate(&value, collection)
+	fmt.Printf("%v\n", value)
+	fmt.Println(err)
+	// Output: {12 stuff {12 }}
+	// field "Recursive": field "String": empty string
+}
+
+func ExampleValidate_notastruct() {
+	var value int
+	err := Validate(&value, nil)
+	fmt.Println(err)
+}
+
+func ExampleValidate_notavalidator() {
+	var value struct {
+		Field int `validate:"generic"`
+	}
+	collection := make(Collection, 2)
+	collection["generic"] = func(x, y int) error {
+		panic("never reached")
+	}
+	err := Validate(&value, collection)
+	fmt.Println(err)
+	// Output: field "Field": entry "generic" in validators is not a valiator
+}
+
+func ExampleValidate_invalid() {
+	var value struct {
+		Field int `validate:"string"`
+	}
+	collection := make(Collection, 2)
+	collection["string"] = func(value *string, dflt string) error {
+		panic("never reached")
+	}
+	err := Validate(&value, collection)
+	fmt.Println(err)
+	// Output: field "Field": validator "string": got type string, expected type int
+}