Use the new context macro in the README examples

README.md

@@ -64,10 +64,10 @@ And you can use **variables** and **functions** in expressions like this:
 use evalexpr::*;
 use evalexpr::error::expect_number;
 
-let mut context = HashMapContext::new();
-context.set_value("five".into(), 5.into()).unwrap(); // Do proper error handling here
-context.set_value("twelve".into(), 12.into()).unwrap(); // Do proper error handling here
-context.set_function("f".into(), Function::new(Some(1) /* argument amount */, Box::new(|arguments| {
+let context = context_map! {
+  "five" => 5,
+  "twelve" => 12,
+  "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] {
@@ -75,8 +75,8 @@ context.set_function("f".into(), Function::new(Some(1) /* argument amount */, Bo
       } 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])?;
 
@@ -85,7 +85,8 @@ context.set_function("avg".into(), Function::new(Some(2) /* argument amount */,
       } else {
           Ok(Value::Float((arguments[0].as_number()? + arguments[1].as_number()?) / 2.0))
       }
-}))).unwrap(); // Do proper error handling here
+  }))
+ }.unwrap();
 
 assert_eq!(eval_with_context("five + 8 > f(twelve)", &context), Ok(Value::from(true)));
 // `eval_with_context` returns a variant of the `Value` enum,
@@ -102,10 +103,11 @@ use evalexpr::*;
 
 let precompiled = build_operator_tree("a * b - c > 5").unwrap(); // Do proper error handling here
 
-let mut context = HashMapContext::new();
-context.set_value("a".into(), 6.into()).unwrap(); // Do proper error handling here
-context.set_value("b".into(), 2.into()).unwrap(); // Do proper error handling here
-context.set_value("c".into(), 3.into()).unwrap(); // Do proper error handling here
+let mut context = context_map! {
+  "a" => 6,
+  "b" => 2,
+  "c" => 3
+}.unwrap();
 assert_eq!(precompiled.eval_with_context(&context), Ok(Value::from(true)));
 
 context.set_value("c".into(), 8.into()).unwrap(); // Do proper error handling here