diff --git a/README.md b/README.md
index 408cd10..fda8cac 100644
--- a/README.md
+++ b/README.md
@@ -6,4 +6,133 @@ Evalexpr is a powerful arithmetic and boolean expression evaluator.
 
 ## [Documentation](https://docs.rs/evalexpr)
 
-<!-- cargo-sync-readme -->
\ No newline at end of file
+<!-- cargo-sync-readme start -->
+
+
+ ## Features
+
+ Supported binary operators:
+
+ | Operator | Description |
+ |----------|-------------|
+ | + | Sum |
+ | - | Difference |
+ | * | Product |
+ | / | Division |
+ | % | Modulo |
+ | < | Lower than |
+ | \> | Greater than |
+ | <= | Lower than or equal |
+ | \>= | Greater than or equal |
+ | == | Equal |
+ | != | Not equal |
+ | `&&` | Logical and |
+ | `||` | Logical or |
+ 
+Supported binary operators: `!` `!=` `""` `''` `()` `[]` `,` `>` `<` `>=` `<=` `==`
+`+` unary/binary `-` `*` `/` `%` `&&` `||` `n..m`.
+
+Supported unary operators: ``
+
+Built-in functions: `min()` `max()` `len()` `is_empty()` `array()` `converge()`.
+See the `builtin` module for a detailed description of each.
+
+Where can eval be used?
+-----------------------
+
+* Template engine
+* Scripting language
+* ...
+
+Usage
+-----
+
+Add dependency to Cargo.toml
+
+```toml
+[dependencies]
+evalexpr = "0.4"
+```
+
+In your `main.rs` or `lib.rs`:
+
+```rust
+extern crate evalexpr as eval;
+```
+
+Examples
+--------
+
+You can do mathematical calculations with supported operators:
+
+```rust
+use eval::{eval, to_value};
+
+assert_eq!(eval("1 + 2 + 3"), Ok(to_value(6)));
+assert_eq!(eval("2 * 2 + 3"), Ok(to_value(7)));
+assert_eq!(eval("2 / 2 + 3"), Ok(to_value(4.0)));
+assert_eq!(eval("2 / 2 + 3 / 3"), Ok(to_value(2.0)));
+```
+
+You can eval with context:
+
+```rust
+use eval::{Expr, to_value};
+
+assert_eq!(Expr::new("foo == bar")
+               .value("foo", true)
+               .value("bar", true)
+               .exec(),
+           Ok(to_value(true)));
+```
+
+You can access data like javascript by using `.` and `[]`. `[]` supports expression.
+
+```rust
+use eval::{Expr, to_value};
+use std::collections::HashMap;
+
+let mut object = HashMap::new();
+object.insert("foos", vec!["Hello", "world", "!"]);
+
+assert_eq!(Expr::new("object.foos[1-1] == 'Hello'")
+               .value("object", object)
+               .exec(),
+           Ok(to_value(true)));
+```
+
+You can eval with function:
+
+```rust
+use eval::{Expr, to_value};
+
+assert_eq!(Expr::new("say_hello()")
+               .function("say_hello", |_| Ok(to_value("Hello world!")))
+               .exec(),
+           Ok(to_value("Hello world!")));
+```
+
+You can create an array with `array()`:
+
+```rust
+use eval::{eval, to_value};
+
+assert_eq!(eval("array(1, 2, 3, 4, 5)"), Ok(to_value(vec![1, 2, 3, 4, 5])));
+```
+
+You can create an integer array with `n..m`:
+
+```rust
+use eval::{eval, to_value};
+
+assert_eq!(eval("0..5"), Ok(to_value(vec![0, 1, 2, 3, 4])));
+```
+
+License
+-------
+
+evalexpr is primarily distributed under the terms of the MIT license.
+See [LICENSE](LICENSE) for details. 
+
+
+<!-- cargo-sync-readme end -->
diff --git a/src/lib.rs b/src/lib.rs
index 3f87e3c..2f8c18e 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -3,7 +3,21 @@
 //!
 //! Supported binary operators:
 //!
-//! | + | - | * | % | < | > | <= | >= | == | && | || |
+//! | Operator | Description |
+//! |----------|-------------|
+//! | + | Sum |
+//! | - | Difference |
+//! | * | Product |
+//! | / | Division |
+//! | % | Modulo |
+//! | < | Lower than |
+//! | > | Greater than |
+//! | <= | Lower than or equal |
+//! | >= | Greater than or equal |
+//! | == | Equal |
+//! | != | Not equal |
+//! | && | Logical and |
+//! | || | Logical or |
 //! 
 //!Supported binary operators: `!` `!=` `""` `''` `()` `[]` `,` `>` `<` `>=` `<=` `==`
 //!`+` unary/binary `-` `*` `/` `%` `&&` `||` `n..m`.