Rework the type system

Author: vektah

README.md

@@ -10,19 +10,17 @@ get used.
 
 #### Getting started
 
-First grab it:
+From inside the package you want to have the dataloader in:
 ```bash
-go get -u github.com/vektah/dataloaden
+go run github.com/vektah/dataloaden UserLoader string *github.com/dataloaden/example.User
 ```
 
-then from inside the package you want to have the dataloader in:
-```bash
-dataloaden github.com/dataloaden/example.User
-```
+This will generate a dataloader called `UserLoader` that looks up `*github.com/dataloaden/example.User`'s objects 
+based on a `string` key. 
 
 In another file in the same package, create the constructor method:
 ```go
-func NewLoader() *UserLoader {
+func NewUserLoader() *UserLoader {
 	return &UserLoader{
 		wait:     2 * time.Millisecond,
 		maxBatch: 100,
@@ -41,7 +39,7 @@ func NewLoader() *UserLoader {
 
 Then wherever you want to call the dataloader
 ```go
-loader := NewLoader()
+loader := NewUserLoader()
 
 user, err := loader.Load("123")
 ```
@@ -51,13 +49,14 @@ function once. It also caches values and wont request duplicates in a batch.
 
 #### Returning Slices
 
-You may want to generate a dataloader that returns slices instead of single values. This can be done using the `-slice` flag:
+You may want to generate a dataloader that returns slices instead of single values. Both key and value types can be a 
+simple go type expression: 
 
 ```bash
-dataloaden -slice github.com/dataloaden/example.User
+go run github.com/vektah/dataloaden UserSliceLoader string []*github.com/dataloaden/example.User
 ```
 
-Now each key is expected to return a slice of values and the `fetch` function has the return type `[][]User`.
+Now each key is expected to return a slice of values and the `fetch` function has the return type `[][]*User`.
 
 #### Using with go modules
 

dataloaden.go

@@ -1,32 +1,27 @@
 package main
 
 import (
-	"flag"
 	"fmt"
 	"os"
 
 	"github.com/vektah/dataloaden/pkg/generator"
 )
 
 func main() {
-	keyType := flag.String("keys", "int", "what type should the keys be")
-	slice := flag.Bool("slice", false, "this dataloader will return slices")
-
-	flag.Parse()
-
-	if flag.NArg() != 1 {
-		flag.Usage()
+	if len(os.Args) != 4 {
+		fmt.Println("usage: name keyType valueType")
+		fmt.Println(" example:")
+		fmt.Println(" dataloaden 'UserLoader int []*github.com/my/package.User'")
 		os.Exit(1)
 	}
 
 	wd, err := os.Getwd()
-
 	if err != nil {
 		fmt.Fprintln(os.Stderr, err.Error())
 		os.Exit(2)
 	}
 
-	if err := generator.Generate(flag.Arg(0), *keyType, *slice, wd); err != nil {
+	if err := generator.Generate(os.Args[1], os.Args[2], os.Args[3], wd); err != nil {
 		fmt.Fprintln(os.Stderr, err.Error())
 		os.Exit(2)
 	}

example/pkgname/user.go

@@ -1,3 +1,3 @@
 package differentpkg
 
-//go:generate go run github.com/vektah/dataloaden -keys string github.com/vektah/dataloaden/example.User
+//go:generate go run github.com/vektah/dataloaden UserLoader string *github.com/vektah/dataloaden/example.User

example/pkgname/userloader_gen.go

@@ -1,4 +1,4 @@
-//go:generate go run github.com/vektah/dataloaden -keys int -slice github.com/vektah/dataloaden/example.User
+//go:generate go run github.com/vektah/dataloaden UserSliceLoader int []github.com/vektah/dataloaden/example.User
 
 package slice