lezer-feel


This is a DMN FEEL grammar for the
Lezer parser system.

Usage

Parse FEEL to a Tree:

``javascript
import {
parser
} from 'lezer-feel';

// parse
parser.parse('foo > 1');
`


#### Choose Dialect

Use Expression or UnaryTests as a top node depending on which FEEL dialect you intend to parse:

`javascript
import {
parser
} from 'lezer-feel';

const unaryParser = parser.configure({
top: 'UnaryTests'
})

// parse
unaryParser.parse('> 100');
`


#### Provide Context

Override the default context tracker to enable context sensitive parsing based on inputs:

`javascript
import {
parser,
trackVariables
} from 'lezer-feel';

const contextTracker = trackVariables({
'if foo then bar': 1
});

const contextualParser = parser.configure({
contextTracker
});

// recognizes as a
contextualParser.parse('if foo then bar');
`




Development

`shell


build and test

npm run all

test

npm test

test (debug)

LOG=fparse:dbg,fparse,context,parse npm test
`

Prefix individual tests with a * to test them in focus mode:

`markdown


*ArithmeticExpression (error)

...
``

Related

* feelin - Interpreter for the FEEL language
* feel-playground - A visual playground to learn the FEEL language
* lang-feel - Integration into a CodeMirror editor

License

The code is licensed under an MIT license.