serafim/calc

3.2.0 2024-04-08 10:05 UTC

Requires

• php: ^8.1
• phplrt/runtime: ^3.6
• symfony/console: ^5.4|^6.0|^7.0

Requires (Dev)

• phplrt/compiler: ^3.6
• symfony/var-dumper: ^5.4|^6.0|^7.0

MIT

README

Why?

This repository is designed as an example of how you can implement a calculator based on abstract syntax tree generated by the LL(k) recurrence recursive descent parser.

As a grammar used the basic implementation with operators associativity, and not vulnerable to left recursion:

{
  tokens = [
    T_FLOAT = "regexp:\d+\.\d+"
    T_INT   = "regexp:\d+"
  ]
}

<expr>           ::= <addition> | <subtraction> | <term>

<term>           ::= <multiplication> | <division> | <factor>
<factor>         ::= "(" <expr> ")" | <value>

<subtraction>    ::= <term> "-" <expr>
<addition>       ::= <term> "+" <expr>
<multiplication> ::= <factor> "*" <term>
<division>       ::= <factor> ("/" | "÷") <term>

<value>          ::= T_FLOAT | T_INT

Example

Command Line Interface

$ php ./bin/cc run

Usage

Global:

$ composer global require serafim/calc
$ cc run

Local:

$ composer require serafim/calc
$ ./vendor/bin/cc run