Setup

This uses Node.js 10.15.0 with npm 6.4.1. Install nvm

curl -o- https://raw.githubusercontent.com/creationix/nvm/v0.34.0/install.sh | bash

and then

nvm install && nvm use

to get the right verson of Node.js. npm i -g 6.4.1 to get the right version of npm.

Alternately, install Docker and use the dockerized build & run commands. In that case you won't need any dependencies other than Docker to run the API. You'll still need Node.js and npm to run the test suite, however.

Usage

To start the api locally:

npm start

or to run it with docker:

npm run docker:build && npm run docker:run

Calling the api:

POST /parse with JSON body { "input": "<input>" }. Response is of the form { "output": <output tree> }

Sample request:

curl localhost/parse -H "Content-Type: application/json" --data '{"input":"test AND 3.5 AND 3 AND true AND !false OR (>3 OR <5) AND >=3.5 AND <=5 AND =6 AND \"6 AND 7\""}'

Sample response:

{"output":{"$or":[{"$and":[{"$and":[{"$and":[{"$and":["test",3.5]},3]},true]},{"$not":false}]},{"$and":[{"$and":[{"$and":[{"$and":[{"$or":[{"$gt":3},{"$lt":5}]},{"$ge":3.5}]},{"$le":5}]},{"$eq":6}]},{"$quoted":"6 AND 7"}]}]}}

Test suite

npm t

to run the test suite.

Caveats

• The way I implemented it, the parser cannot handle extra spaces. If I were to do this again I would change it to make that feasable by trimming all whitespace and then, in the parser, implicitly ANDing any two adjacent nodes with no infixed operator.
• The error handling is not robust. Some obvious errors are caught but I'm sure there are plenty of edge cases that are not dealt with gracefully.