Refactor

Move all the business logic of parsing and generating code
into maker subpackage.

Instead of functions, the maker package exports a Maker struct,
which has two exported methods: ParseSource to add a file,
and MakeInterface to create the interface.

The struct now handles the data that was previously handled
by the main package between the invocation of the two functions.

Don't use token.Pos to access source file byte slice,
this doesn't work when there are multiple files in the fileset.
Use go/printer or directly get the parsed strings from the ast nodes.

Ignore dot imports, assume they will not be needed by the
generated struct.

Throw errors when aliases conflict or a package is imported
with different aliases (vburenin#9).

Add a "Code generated by" comment per
https://golang.org/s/generatedcode

Add tests + travis.

.travis.yml

@@ -0,0 +1,11 @@
+language: go
+go:
+  - 1.4
+  - 1.5
+  - 1.6
+  - 1.7
+  - 1.8
+  - tip
+sudo: false
+go_import_path: github.com/vburenin/ifacemaker # required for forks to build properly
+install: scripts/deps.sh

ifacemaker.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"io/ioutil"
 	"log"
+	"path/filepath"
 
 	"github.com/mkideal/cli"
 	"github.com/vburenin/ifacemaker/maker"
@@ -20,31 +21,22 @@ type cmdlineArgs struct {
 }
 
 func run(args *cmdlineArgs) {
-	allMethods := []string{}
-	allImports := []string{}
-	mset := make(map[string]struct{})
-	iset := make(map[string]struct{})
+	maker := &maker.Maker{
+		StructName: args.StructType,
+		CopyDocs:   args.CopyDocs,
+	}
 	for _, f := range args.Files {
 		src, err := ioutil.ReadFile(f)
 		if err != nil {
 			log.Fatal(err.Error())
 		}
-		methods, imports := maker.ParseStruct(src, args.StructType, args.CopyDocs)
-		for _, m := range methods {
-			if _, ok := mset[m.Code]; !ok {
-				allMethods = append(allMethods, m.Lines()...)
-				mset[m.Code] = struct{}{}
-			}
-		}
-		for _, i := range imports {
-			if _, ok := iset[i]; !ok {
-				allImports = append(allImports, i)
-				iset[i] = struct{}{}
-			}
+		err = maker.ParseSource(src, filepath.Base(f))
+		if err != nil {
+			log.Fatal(err.Error())
 		}
 	}
 
-	result, err := maker.MakeInterface(args.PkgName, args.IfaceName, allMethods, allImports)
+	result, err := maker.MakeInterface(args.PkgName, args.IfaceName)
 	if err != nil {
 		log.Fatal(err.Error())
 	}