Use context_map macro in lib.rs documentation as well

Should have used `cargo sync-readme` to begin with, but that was not
documented at the time of this pull request.

README.md

@@ -86,7 +86,7 @@ let context = context_map! {
             Ok(Value::Float((arguments[0].as_number()? + arguments[1].as_number()?) / 2.0))
         }
     }))
- }.unwrap();
+}.unwrap(); // Do proper error handling here
 
 assert_eq!(eval_with_context("five + 8 > f(twelve)", &context), Ok(Value::from(true)));
 // `eval_with_context` returns a variant of the `Value` enum,
@@ -107,7 +107,7 @@ let mut context = context_map! {
     "a" => 6,
     "b" => 2,
     "c" => 3
-}.unwrap();
+}.unwrap(); // Do proper error handling here
 assert_eq!(precompiled.eval_with_context(&context), Ok(Value::from(true)));
 
 context.set_value("c".into(), 8.into()).unwrap(); // Do proper error handling here
@@ -345,8 +345,9 @@ Example parsing with [ron format](docs.rs/ron):
 extern crate ron;
 use evalexpr::*;
 
-let mut context = HashMapContext::new();
+let mut context = context_map!{
-context.set_value("five".into(), 5.into()).unwrap(); // Do proper error handling here
+    "five" => 5
+}.unwrap(); // Do proper error handling here
 
 // In ron format, strings are surrounded by "
 let serialized_free = "\"five * five\"";

src/lib.rs

@@ -51,10 +51,10 @@
 //! use evalexpr::*;
 //! use evalexpr::error::expect_number;
 //!
-//! let mut context = HashMapContext::new();
+//! let context = context_map! {
-//! context.set_value("five".into(), 5.into()).unwrap(); // Do proper error handling here
+//!     "five" => 5,
-//! context.set_value("twelve".into(), 12.into()).unwrap(); // Do proper error handling here
+//!     "twelve" => 12,
-//! context.set_function("f".into(), Function::new(Some(1) /* argument amount */, Box::new(|arguments| {
+//!     "f" => Function::new(Some(1) /* argument amount */, Box::new(|arguments| {
 //!         if let Value::Int(int) = arguments[0] {
 //!             Ok(Value::Int(int / 2))
 //!         } else if let Value::Float(float) = arguments[0] {
@@ -62,8 +62,8 @@
 //!         } else {
 //!             Err(EvalexprError::expected_number(arguments[0].clone()))
 //!         }
-//! }))).unwrap(); // Do proper error handling here
+//!     })),
-//! context.set_function("avg".into(), Function::new(Some(2) /* argument amount */, Box::new(|arguments| {
+//!     "avg" => Function::new(Some(2) /* argument amount */, Box::new(|arguments| {
 //!         expect_number(&arguments[0])?;
 //!         expect_number(&arguments[1])?;
 //!
@@ -72,7 +72,8 @@
 //!         } else {
 //!             Ok(Value::Float((arguments[0].as_number()? + arguments[1].as_number()?) / 2.0))
 //!         }
-//! }))).unwrap(); // Do proper error handling here
+//!     }))
+//! }.unwrap(); // Do proper error handling here
 //!
 //! assert_eq!(eval_with_context("five + 8 > f(twelve)", &context), Ok(Value::from(true)));
 //! // `eval_with_context` returns a variant of the `Value` enum,
@@ -89,10 +90,11 @@
 //!
 //! let precompiled = build_operator_tree("a * b - c > 5").unwrap(); // Do proper error handling here
 //!
-//! let mut context = HashMapContext::new();
+//! let mut context = context_map! {
-//! context.set_value("a".into(), 6.into()).unwrap(); // Do proper error handling here
+//!     "a" => 6,
-//! context.set_value("b".into(), 2.into()).unwrap(); // Do proper error handling here
+//!     "b" => 2,
-//! context.set_value("c".into(), 3.into()).unwrap(); // Do proper error handling here
+//!     "c" => 3
+//! }.unwrap(); // Do proper error handling here
 //! assert_eq!(precompiled.eval_with_context(&context), Ok(Value::from(true)));
 //!
 //! context.set_value("c".into(), 8.into()).unwrap(); // Do proper error handling here
@@ -330,8 +332,9 @@
 //! extern crate ron;
 //! use evalexpr::*;
 //!
-//! let mut context = HashMapContext::new();
+//! let mut context = context_map!{
-//! context.set_value("five".into(), 5.into()).unwrap(); // Do proper error handling here
+//!     "five" => 5
+//! }.unwrap(); // Do proper error handling here
 //!
 //! // In ron format, strings are surrounded by "
 //! let serialized_free = "\"five * five\"";