JsepSharp.Plugins 1.3.8.1

JsepSharp Plugins

These are the standard optional plugins for the JsepSharp parser. They add support for functionality not available in the core implementation.

Usage

// Create instance to use with plugins:
var j = new Jsep("a ? b : c");
j.RegisterPlugin(typeof(TernaryPlugin));
j.Parse();

// Static parse method with all built-in plugins:
Jsep.Parse("f = (a) => ({ b: 4, c: (d > 4 ? 4 : d), e: /^[a-z]{5}$/ })", BuiltIns.All);

// Static parse method With specific plugins:
Jsep.Parse("a => b ? c : d", new[] { typeof(TernaryPlugin), typeof(ArrowPlugin) });

Note: Plugin inclusion order matters. Ternary should generally be included before other plugins, if it is being used.

Plugins

The plugins work differently from the JavaScript version, due to language differences.

None are included by default, which is a difference from the JavaScript implementation that includes ternary by default.

Included Plugins

How to Add Plugins

1. Class/Static Parse method: Supply the second argument with an enumerable of System.Type for each plugin.

2. Instance RegisterPlugin method: After creating an instance, invoke RegisterPlugin with the System.Type of the plugin.

Regardlesss of how you register them, the plugin class must implement abstract class Jsep.Plugin . If it does not, an ArgumentException will be raised.

List Plugins

Installed plug-ins can be enumerated from a Jsep instance via the Plugins property.

Writing Your Own Plugin

Hooks (Events)

The hooks system uses C# events, which differs from the JavaScript implementation. This was done since the C# language already has the necessary feature built-in.

These exist to provide extensibility points that plugins can use to integrate into the parser and add additional functionality to it.

Hook Types

• BeforeParsing: called just before starting all expression parsing. Port of before-all
• AfterParsing: called after parsing all. Read/Write env.Node as required. Port of after-all.
• BeforeExpression: called just before attempting to parse an expression. Set env.Node as required. Port of gobble-expression.
• AfterExpression: called just after parsing an expression. Read/Write env.Node as required. Port of after-expression.
• BeforeToken: called just before attempting to parse a token. Set env.Node as required. Port of gobble-token.
• AfterToken: called just after parsing a token. Read/Write env.Node as required. Port of after-token.
• AfterSpaces: called when gobbling whitespace. Port of gobble-spaces.

Examples

• The Spread plugin is the smallest of the bulit-ins.
• The AsyncAwait plugin demonstrates how to declare a plugin depends upon another plugin.
• The Arrow plugin shows how to use ReplaceNodes() to alter previously parsed results.
• The Comment plugin shows how to instruct the parser to ignore additional sequences.
• The New plugin swaps out a node with a new type of node.
• The Regex plugin shows how to create a new type of literal to the parser.
• The Number plugin shows how to extend the parsing behavior of an existing literal.

License

The JsepSharp Plugins are a derivative work under the MIT license. See LICENSE file.

Thanks

To all the contributors of the original jsep project.