easeeval

EaseEval

EaseEval is a simple text eval tool, built on DSL, written in Go.

1. Overview

EaseEval is designed to extract values from text and evaluate expressions using a DSL, which contains Function, Typecast and Compute.

1.1 Function

Function is very useful in many scenarios, we plan to supply different kind of functions.

1.1.1 Extract Function

Extract functions extract target values from source text in many types: plain text, json, html, xml, etc.

• jq. extract values from json format text using jq
• regex. extract values from text using regex (to be implemented)

1.1.2 Time Function

Time functions supply ways to get unix time from string or for now.

• unixTime return unix time seconds in int64 for any format string using dateparse
• now return unix time seconds in int64 for now

1.1.3 Other Function (to be implemented)

1.2 Typecast

Typecast auto converts values on demand to specific types like string, number, date, etc. We support types below.

• bool. bool type can be used in assertions
• int64. int64 is the only int type supported, other int type like int8,int32 and int strings will auto be converted to int64.
• datetime. (to be implemented)
• other types. (to be implemented)

1.3 Compute

Compute does the actual eval work for different operators.

• logical operators. &&, ||, !
• arithmetic operators. +, -, *, /
• relational operators. >, <, ==, !=, >=, <=
• other operators. (to be implemented)

2 Usage

2.1 Installation

go get github.com/samanhappy/easeeval

2.2 Example

package main

import (
	"fmt"

	"github.com/samanhappy/easeeval"
)

func main() {
	// pure eval
	v, _ := easeeval.Eval(`1 + 2 * 3`, "")
	fmt.Printf("value %v, type %T\n", v, v)

	// use jq to extract value for eval
	v, _ = easeeval.Eval(`1 + jq(".key") * 3`, `{"key":"2"}`)
	fmt.Printf("value %v, type %T\n", v, v)
}