doc: document import of source and binary packages (#477)

interp/doc.go

@@ -4,6 +4,18 @@ Package interp provides a complete Go interpreter.
 For the Go language itself, refer to the official Go specification
 https://golang.org/ref/spec.
 
+Importing packages
+
+Packages can be imported in source or binary form, using the standard
+Go import statement. In source form, packages are searched first in the
+vendor directory, the preferred way to store source dependencies. If not
+found in vendor, sources modules will be searched in GOPATH. Go modules
+are not supported yet by yaegi.
+
+Binary form packages are compiled and linked with the interpreter
+executable, and exposed to scripts with the Use method. The goexports
+command can be used to generate package wrappers.
+
 Custom build tags
 
 Custom build tags allow to control which files in imported source

stdlib/stdlib.go

@@ -1,5 +1,6 @@
 // +build go1.12,!go1.14
 
+// Package stdlib provides wrappers of standard library packages to be imported natively in Yaegi.
 package stdlib
 
 import "reflect"

stdlib/syscall/syscall.go

@@ -1,5 +1,6 @@
 // +build go1.12,!go1.14
 
+// Package syscall provide wrapper of standard library syscall package for native import in Yaegi.
 package syscall
 
 import "reflect"

stdlib/unsafe/unsafe.go

@@ -1,5 +1,6 @@
 // +build go1.12,!go1.14
 
+// Package unsafe provides wrapper of standard library unsafe package to be imported natively in Yaegi.
 package unsafe
 
 import "reflect"