add docs

README.md

@@ -1,14 +1,24 @@
 # Loading Cache Wrapper [![Build Status](https://travis-ci.org/go-pkgz/lcw.svg?branch=master)](https://travis-ci.org/go-pkgz/lcw) [![Coverage Status](https://coveralls.io/repos/github/go-pkgz/lcw/badge.svg?branch=master)](https://coveralls.io/github/go-pkgz/lcw?branch=master) [![godoc](https://godoc.org/github.com/go-pkgz/lcw?status.svg)](https://godoc.org/github.com/go-pkgz/lcw)
 
 
-The library adds a thin layer on top of [lru cache](https://github.com/hashicorp/golang-lru).
+The library adds a thin layer on top of [lru cache](https://github.com/hashicorp/golang-lru) and [patrickmn/go-cache](https://github.com/patrickmn/go-cache).
 
+It exposes 3 caches, implementing `LoadingCache` interface:
+
+1. `LruCache` - LRU cache with limits, created with `lcw.NewLruCache`
+1. `ExpirableCache` - TTL cache with limits, created with `lcw.NewExpirableCache`
+1. `Nop` - do-nothing cache
+
+Main features:
+
 - LoadingCache (guava style)
 - Limit maximum cache size (in bytes)
 - Limit maximum key size
 - Limit maximum size of a value 
+- TTL support (`ExpirableCache` only)
 - Functional style invalidation
-- Nop cache provided
+- Functional options
+- Sane defaults
 
 ## Install and update
 
@@ -17,7 +27,7 @@ The library adds a thin layer on top of [lru cache](https://github.com/hashicorp
 ## Usage
 
 ```
-cache := lcw.NewCache(lcw.MaxKeys(500), lcw.MaxCacheSize(65536), lcw.MaxValSize(200), lcw.MaxKeySize(32))
+cache := lcw.NewLruCache(lcw.MaxKeys(500), lcw.MaxCacheSize(65536), lcw.MaxValSize(200), lcw.MaxKeySize(32))
 
 val, err := cache.Get("key123", func() (lcw.Value, error) {
     res, err := getDataFromSomeSource(params) // returns string
@@ -37,4 +47,4 @@ s := val.(string) // cached value
 - All byte-size limits work for values implementing `lcw.Sizer` interface
 - Negative limits (max options) rejected
 - `lgr.Value` wraps `interface{}` and should be converted back to the concrete type.
-- The implementation started as a part of [remark42](https://github.com/umputun/remark) and later on moved to [go-pkgz/rest](https://github.com/go-pkgz/rest/tree/master/cache) library.
+- The implementation started as a part of [remark42](https://github.com/umputun/remark) and later on moved to [go-pkgz/rest](https://github.com/go-pkgz/rest/tree/master/cache) library and finaly generalized to become `lcw`.

interface.go

@@ -23,6 +23,11 @@ type LoadingCache interface {
 // Nop is do-nothing implementation of LoadingCache
 type Nop struct{}
 
+// NewNopCache makes new do-nothing cache
+func NewNopCache() *Nop {
+	return &Nop{}
+}
+
 // Get calls fn without any caching
 func (n *Nop) Get(key string, fn func() (Value, error)) (Value, error) { return fn() }
 

interface_test.go

@@ -9,7 +9,7 @@ import (
 
 func TestNop_Get(t *testing.T) {
 	var coldCalls int32
-	c := Nop{}
+	c := NewNopCache()
 	res, err := c.Get("key1", func() (Value, error) {
 		atomic.AddInt32(&coldCalls, 1)
 		return "result", nil
@@ -29,7 +29,7 @@ func TestNop_Get(t *testing.T) {
 
 func TestNop_Peek(t *testing.T) {
 	var coldCalls int32
-	c := Nop{}
+	c := NewNopCache()
 	res, err := c.Get("key1", func() (Value, error) {
 		atomic.AddInt32(&coldCalls, 1)
 		return "result", nil