platform/packages/code_buffer/README.md
thomashii@dukefirehawk.com 5a4dd0fb2b Publish angel3_code_buffer
2021-05-14 11:06:32 +08:00

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# angel3_code_buffer
[![version](https://img.shields.io/badge/pub-v2.12.4-brightgreen)](https://pub.dartlang.org/packages/angel3_code_buffer)
[![Null Safety](https://img.shields.io/badge/null-safety-brightgreen)](https://dart.dev/null-safety)
[![License](https://img.shields.io/github/license/dukefirehawk/angel)](https://github.com/dukefirehawk/angel/tree/angel3/code_buffer)
An advanced StringBuffer geared toward generating code, and source maps.
# Installation
In your `pubspec.yaml`:
```yaml
dependencies:
angel3_code_buffer: ^2.0.0
```
# Usage
Use a `CodeBuffer` just like any regular `StringBuffer`:
```dart
String someFunc() {
var buf = CodeBuffer();
buf
..write('hello ')
..writeln('world!');
return buf.toString();
}
```
However, a `CodeBuffer` supports indentation.
```dart
void someOtherFunc() {
var buf = CodeBuffer();
// Custom options...
var buf = CodeBuffer(newline: '\r\n', space: '\t', trailingNewline: true);
// Any following lines will have an incremented indentation level...
buf.indent();
// And vice-versa:
buf.outdent();
}
```
`CodeBuffer` instances keep track of every `SourceSpan` they create.
This makes them useful for codegen tools, or to-JS compilers.
```dart
void someFunc(CodeBuffer buf) {
buf.write('hello');
expect(buf.lastLine.text, 'hello');
buf.writeln('world');
expect(buf.lastLine.lastSpan.start.column, 5);
}
```
You can copy a `CodeBuffer` into another, heeding indentation rules:
```dart
void yetAnotherFunc(CodeBuffer a, CodeBuffer b) {
b.copyInto(a);
}
```