Logic Query Parser

Generate binary tree with a logic query string as input.

How to install?

``
npm install
`

Check everything is working with npm test.

How to use it

This lib provides a function parser whick take an optional options object and a string parameter, then returning a binary tree.
As binary trees are not easy to use, this lib also provides an utility function which convert said binaryTree to a more usable query form

Avalaible options are for now :
* spaces : String / array containing all spaces characters. Default : " \n\t"
* defaultOperator : Default operator to use between two strings. Default : 'and'

Available operators for now : AND, OR, parens, double quote

This extended version adds the NOT (alias !) operator as well as comparison operators:
* < (lt - lower than)
* <= (lte - lower than or equal)
* \> (gt - greater than)
* \>= (gte - greater than or equal)
* = (e - is equal)
* != (ne - is not equal)

Example

`js
var parser = require('logic-query-parser');

var binaryTree = parser.parse('hello AND welcome');
`

The binaryTree for this example will be :
`js
{
lexeme: {
type: 'and'
},
left: {
lexeme: {
type: 'string',
value: 'hello'
},
left: null,
right: null
},
right: {
lexeme: {
type: 'string',
value: 'welcome'
},
left: null,
right: null
}
}
`

Another example, slightly more complex:

`js
var parser = require('logic-query-parser');

var binaryTree = parser.parse('(welcome OR bye) AND (hello OR ahoy)');
`

And the binary tree :
`js
{
lexeme: {
type: "and"
},
left: {
lexeme: {
type: "or"
},
left: {
lexeme: {
type: "string",
value: "welcome"
},
left: null,
right: null
},
right: {
lexeme: {
type: "string",
value: "bye"
},
left: null,
right: null
}
},
right: {
lexeme: {
type: "or"
},
left: {
lexeme: {
type: "string",
value: "hello"
},
left: null,
right: null
},
right: {
lexeme: {
type: "string",
value: "ahoy"
},
left: null,
right: null
}
}
}
`

NOT operator and comparison example:

`js
var parser = require('logic-query-parser');

var binaryTree = parser.parse('a > 1 and not b <= 10');
`

The binary tree will be:
`js
{
"lexeme": {
"type": "and"
},
"left": {
"lexeme": {
"type": "gt"
},
"left": {
"lexeme": {
"type": "string",
"value": "a"
},
"left": null,
"right": null
},
"right": {
"lexeme": {
"type": "string",
"value": "1"
},
"left": null,
"right": null
}
},
"right": {
"lexeme": {
"type": "not"
},
"left": null,
"right": {
"lexeme": {
"type": "lte"
},
"left": {
"lexeme": {
"type": "string",
"value": "b"
},
"left": null,
"right": null
},
"right": {
"lexeme": {
"type": "string",
"value": "10"
},
"left": null,
"right": null
}
}
}
}
`

As said before, trees are useful but not easy to use. You can also get the "query form":

`js
var parser = require('logic-query-parser');

var binaryTree = parser.parse('(welcome OR bye) AND (hello OR ahoy)');
var query = parser.utils.binaryTreeToQueryJson(binaryTree);
`

Returning:
`js
{
type: "and",
values: [
{
type: "or",
values: [
{
type: "string",
value: "welcome"
},
{
type: "string",
value: "bye"
}
]
},
{
type: "or",
values: [
{
type: "string",
value: "hello"
},
{
type: "string",
value: "ahoy"
}
]
}
]
}
`


Take a look at config/tests.js` for more samples