Simple implementation of a parser and interpretor

Purpose:

• build formulas with simple arithmetic operators (+, -, *, /) and functions (replace, concat).
• provide custom functions
• Validate syntax
• execute in context: provide values for the variables used in the formula

How

A formula is essentially a list of tokens. Tokens are constants, variables, operators, functions and punctuation. A syntactically valid formulas can be evaluated. A context is an object containing the variables used in the formula. Given a context, a valid formula can be evaluated and return a string or a number.

Examples:

build a formula

const formula: Token[] = [
    constant(42),
    operation("+"),
    punctuation("("),
    variable("A"),
    operation("-"),
    constant("1"),
    punctuation(")"),
]

validate a formula

formuleMagique.validate(formula) // { isValid: true}
formuleMagique.validate(formula) // { isValid: false, comment: "invalid operation"}

evaluate a formula against a context

const context = {intro: "Hello, ", outro: "World !"}
const result = formuleMagique.evaluate(formula, context)