71 lines
1.5 KiB
Markdown
71 lines
1.5 KiB
Markdown
<!-- Note: This file is automatically generated from source code comments. Changes made in this file will be overridden. -->
|
|
|
|
# Function parser
|
|
|
|
Create a parser. The function creates a new `math.Parser` object.
|
|
|
|
|
|
## Syntax
|
|
|
|
```js
|
|
math.parser()
|
|
```
|
|
|
|
### Parameters
|
|
|
|
Parameter | Type | Description
|
|
--------- | ---- | -----------
|
|
|
|
|
|
### Returns
|
|
|
|
Type | Description
|
|
---- | -----------
|
|
Parser | Parser
|
|
|
|
|
|
### Throws
|
|
|
|
Type | Description
|
|
---- | -----------
|
|
|
|
|
|
## Examples
|
|
|
|
```js
|
|
const parser = new math.parser()
|
|
|
|
// evaluate expressions
|
|
const a = parser.evaluate('sqrt(3^2 + 4^2)') // 5
|
|
const b = parser.evaluate('sqrt(-4)') // 2i
|
|
const c = parser.evaluate('2 inch in cm') // 5.08 cm
|
|
const d = parser.evaluate('cos(45 deg)') // 0.7071067811865476
|
|
|
|
// define variables and functions
|
|
parser.evaluate('x = 7 / 2') // 3.5
|
|
parser.evaluate('x + 3') // 6.5
|
|
parser.evaluate('f(x, y) = x^y') // f(x, y)
|
|
parser.evaluate('f(2, 3)') // 8
|
|
|
|
// get and set variables and functions
|
|
const x = parser.get('x') // 7
|
|
const f = parser.get('f') // function
|
|
const g = f(3, 2) // 9
|
|
parser.set('h', 500)
|
|
const i = parser.evaluate('h / 2') // 250
|
|
parser.set('hello', function (name) {
|
|
return 'hello, ' + name + '!'
|
|
})
|
|
parser.evaluate('hello("user")') // "hello, user!"
|
|
|
|
// clear defined functions and variables
|
|
parser.clear()
|
|
```
|
|
|
|
|
|
## See also
|
|
|
|
[evaluate](evaluate.md),
|
|
[compile](compile.md),
|
|
[parse](parse.md)
|