tagged-operator
v0.0.3
Published
Simulate operator overloading with Tagged templates
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tagged-operator [alpha]
Simulate operator overloading with Tagged templates
Installation
npm i tagged-operator
Usage
- simple to use
import { createPipeTag } from 'tagged-operator'
const operator = (type, val1, val2) => {
if (type === '~') {
return (val1 + val2) * (val2 + 1 - val1) / 2
}
}
const calc = createPipeTag({ operator })
console.log(calc`${1} ~ ${100}`) // 5050
console.log(calc`${23} ~ ${86}`) // 3488
- use by class, eg Coordinate
const a = new Coordinate(100, 100)
const b = new Coordinate(0, 200)
// a * 3 - b
console.log(a.calc`${a} * ${3} - ${b}`) // Coordinate { x: 300, y: 100 }
- use with TypeScript
import { createTag, Precedence, Operator } from 'tagged-operator'
const precedence: Precedence = { 1: ['*', '/'] }
const operator: Operator<string | number, string> = (type, val1, val2) => {
switch (type) {
case '+':
return String(val1) + String(val2)
case '-':
return String(val1).replace(String(val2), '')
case '*':
if (typeof val1 === 'number' && typeof val2 === 'string') {
return val2.repeat(val1)
} else {
return String(val1).repeat(+val2)
}
case '/':
return String(val1).replaceAll(String(val2), '')
default:
console.warn(`no operator configured: ${type}`)
return String(val1)
}
}
const calc = createTag({ operator, precedence })
console.log(calc`${'Hello'} + ${' World!'}`) // Hello World!
console.log(calc`${'Hello'} * ${3}`) // HelloHelloHello
console.log(calc`(${'Hello'} + ${' World!'}) / ${'l'} - ${'!'}`) // Heo Word
config
type
- Type:
default
|precedence
|pipe
- Default:
default
how to calculate (for the class TaggedOperator
)
default
- the config operator precedence information and grouping operators()
.precedence
- just used the config operator precedence information.pipe
- executes sequentially.
operator
- Required:
true
- Type:
Function(type, val1, val2)
How the match operator is evaluated
type
- current operator (Note: prohibited to use(
and)
when use functioncreateTag
)val1
- the value to the left of the current operatorval2
- the value to the right of the current operator
precedence
- Type:
object
Configure operator precedence information.
The larger the key, the higher the precedence. For performance reasons, you should only config operators that need to be evaluated first.
eg:
const precedence = {
2: ['^'],
1: ['*', '/'],
}
Function
TaggedOperator
Create a tagged calculator through class
createTag
Create a tagged calculator that executes with precedence and grouping operators ()
.
createPrecedenceTag
Create a tagged calculator that only includes precedence information, without grouping operators ()
createPipeTag
Create a tagged calculator that executes sequentially