readme fix and add strict mode toNumber

README.md

@@ -10,29 +10,100 @@ For general information about developing packages, see the Dart guide for
 and the Flutter guide for
 [developing packages and plugins](https://flutter.dev/developing-packages).
 -->
-<a href="https://github.com/serdimoa/big.dart/actions"><img src="https://github.com/serdimoa/big.dart/workflows/big.dart/badge.svg" alt="build"></a>
+![build](https://github.com/serdimoa/big.dart/workflows/big.dart/badge.svg)
 [![Coverage Status](https://coveralls.io/repos/github/serdimoa/big.dart/badge.svg)](https://coveralls.io/github/serdimoa/big.dart)
+[![style: dart lint recommended](https://img.shields.io/badge/style-lints_recommended-40c4ff.svg)](https://pub.dev/packages/lints)
+[![License: MIT](https://img.shields.io/badge/license-MIT-purple.svg)](https://opensource.org/licenses/MIT)
+
+
+A small library for arbitrary-precision decimal arithmetic inspired by [big.js](https://github.com/MikeMcl/big.js/)
 
 ## Features
 
-TODO: List what your package can do. Maybe include images, gifs, or videos.
+- Simple API
+- Easier-to-use
+- Replicates the `toStringAsExponential`, `toStringAsFixed` and `toStringAsPrecision` methods of Dart Numbers
+- Stores values in an accessible decimal floating point format
+- Comprehensive [documentation](http://mikemcl.github.io/big.js/) and test set
+- Uses only Dart, so works in well where Dart work
+
+
+## Use
 
-## Getting started
+*In the code examples below, semicolons and `toString` calls are not shown.*
 
-TODO: List prerequisites and provide or point to information on how to
-start using the package.
+The library exports a single constructor function, `Big`.
+
+A Big number is created from a primitive number, string, or other Big number.
+
+```dart
+var x = Big(123.4567)
+var y = Big('123456.7e-3')
+var z = Big(x)
+x.eq(y) && x.eq(z) && y.eq(z)          // true
+```
 
-## Usage
+In Big strict mode, creating a Big number from a primitive number is disallowed.
+
+```dart
+Big.strict = true
+x = Big(1)                         // TypeError: [big.dart] Invalid number
+y = Big('1.0000000000000001')
+y.toNumber()                           // Error: [big.dart] Imprecise conversion
+```
+
+A Big number is immutable in the sense that it is not changed by its methods.
+
+```dart
+0.3 - 0.1                              // 0.19999999999999998
+x = Big(0.3)
+x.minus(0.1)                           // "0.2"
+x                                      // "0.3"
+```
 
-TODO: Include short and useful examples for package users. Add longer examples
-to `/example` folder.
+The methods that return a Big number can be chained.
 
 ```dart
-const like = 'sample';
+x.div(y).plus(z).times(9).minus('1.234567801234567e+8').plus(976.54321).div('2598.11772')
+x.sqrt().div(y).pow(3).gt(y.mod(z))    // true
 ```
 
-## Additional information
+Like JavaScript's Number type, there are `toExponential`, `toFixed` and `toPrecision` methods.
+
+```dart
+x = Big(255.5)
+x.toExponential(5)                     // "2.55500e+2"
+x.toFixed(5)                           // "255.50000"
+x.toPrecision(5)                       // "255.50"
+```
+
+The arithmetic methods always return the exact result except `div`, `sqrt` and `pow`
+(with negative exponent), as these methods involve division.
+
+The maximum number of decimal places and the rounding mode used to round the results of these methods is determined by the value of the `dp` and `rm` properties of the `Big` number constructor.
+
+```dart
+Big.dp = 10
+Big.rm = Big.roundHalfUp
+x = Big(2);
+y = Big(3);
+z = x.div(y)                           // "0.6666666667"
+z.sqrt()                               // "0.8164965809"
+z.pow(-3)                              // "3.3749999995"
+z.times(z)                             // "0.44444444448888888889"
+z.times(z).round(10)                   // "0.4444444445"
+```
+
+The value of a Big number is stored in a decimal floating point format in terms of a coefficient, exponent and sign.
+
+```javascript
+x = Big(-123.456);
+x.c                                    // [1,2,3,4,5,6]    coefficient (i.e. significand)
+x.e                                    // 2                exponent
+x.s                                    // -1               sign
+```
+
+
+(dart code fully converted to Dart with test and etc.)
+
 
-TODO: Tell users more about the package: where to find more information, how to
-contribute to the package, how to file issues, what response they can expect
-from the package authors, and more.

lib/src/big.dart

@@ -126,7 +126,7 @@ class Big with EquatableMixin {
   /// ************************************************************************************************/
 
   // Error messages.
-  static const name = '[big.js] ';
+  static const name = '[big.dart] ';
   static const invalid = name + 'Invalid ';
   static const invalidDp = invalid + 'decimal places';
   static const invalidRm = invalid + 'rounding mode';
@@ -923,10 +923,12 @@ class Big with EquatableMixin {
   String valueOf() {
     var x = this;
 
-    /// TODO:
-    // if (Big.strict == true) {
-    //   throw Error(NAME + 'valueOf disallowed');
-    // }
+    if (Big.strict == true) {
+      throw BigError(
+        description: name + 'valueOf disallowed',
+        code: BigErrorCode.type,
+      );
+    }
     return stringify(x, x.e <= ne || x.e >= pe, true);
   }
 

pubspec.yaml

@@ -9,7 +9,6 @@ environment:
 
 dependencies:
   equatable: ^2.0.3
-  collection: ^1.15.0
 
 dev_dependencies:
   lints: ^1.0.0