@swim/codec

Swim Codec Library

The Swim Codec library implements an incremental I/O engine, providing:

• functional parsers and writers
• display, debug, and diagnostic formatters
• Unicode and binary codecs

Overview

Inputs and Outputs

An Input reader abstracts over a non-blocking token input stream, with single token lookahead. An Output writer abstracts over a non-blocking token output stream.

Parsers and Writers

A Parser incrementally reads from a sequence of Input chunks to produce a parsed result. A Writer incrementally writes to a sequence of Output chunks.

Binary codecs

The Binary factory has methods to create Input readers that read bytes out of byte buffers, and methods to create Output writers that write bytes into byte buffers.

Text codecs

The Unicode factory has methods to create Input readers that read Unicode code points out of strings, and methods to create Output writers that write Unicode code points into strings.

The Utf8 factory has methods to create Input readers that decode Unicode code points out of UTF-8 encoded byte buffers, and methods to create Output writers that encode Unicode code points into UTF-8 encoded byte buffers.

Binary formats

The Base10 factory has methods to create Parsers that incrementally parse decimal formatted integers, and methods to create Writers that incrementally write decimal formatted integers.

The Base16 factory has methods to create Parsers that incrementally decode hexadecimal encoded text input into byte buffers, and methods to create Writers that incrementally encode byte buffers to hexadecimal encoded text output.

The Base64 factory has methods to create Parsers that incrementally decode base-64 encoded text input into byte buffers, and methods to create Writers that incrementally encode byte buffers to base-64 encoded text output.

Formatters

The Display interface provides a standard way for implementing classes to directly output human readable display strings. Similarly, the Debug interface provides a standard way for implementing classes to directly output developer readable debug strings.

Format provides extension methods to output display and debug strings for all types, including builtin JavaScript types. OutputStyle provides helper functions to conditionally emit ASCII escape codes to stylize text for console output.

Diagnostics

A Tag abstracts over a source input location. A Mark describes a source input position, and a Span describes a source input range. A Diagnostic attaches an informational message to a source input location, and supports displaying the diagnostic as an annotated snippet of the relevant source input.