Initial commit
This commit is contained in:
commit
a6e8d252b1
3
.gitignore
vendored
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3
.gitignore
vendored
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/*.phar
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/vendor
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/composer.lock
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74
README.md
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74
README.md
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# PHP Calc
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The CLI calculator you never knew you needed. Also usable as a library!
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## Usage
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### CLI
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Call with an expression to evaluate:
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$ calc "42*atan(pi/2)"
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42.163162517863
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Or call without arguments to go interactive:
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$ calc
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~ 42*atan(pi/2)
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42.163162517863
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### Library
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As simple as falling off a rock:
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use NoccyLabs\PhpCalc\Calculator;
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$calc = new Calculator();
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$result = $calc->evaluate("42 * atan(pi/2)");
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## What it does
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Supported operations:
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* `+` addition
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* `-` subtraction
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* `*` multiplication
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* `/` division
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* `^` exponent/raise to power
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Supported functions:
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* abs
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* acos
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* acosh
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* asin
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* asin
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* atan
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* atanh
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* ceil
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* cos
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* cosh
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* floor
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* sin
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* sinh
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* log
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* round
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* sqrt
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* tan
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* tanh
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Constants:
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* `pi`
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## Useful tips
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* You can set the precision using the `_p` variable. If the expression is passed on the
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command line, prepend the variable followed by a semicolon, such as `_p=2;pi` for the
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result *3.14*.
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## Bugs and known issues
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* Negative numbers and subtraction should be surrounded by whitespace to parse properly.
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Passing `2-1` will result in `2` and `-1`, returning *2* and a warning. Passing
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`2 - 1` will return `1` as expected, as will `2- 1`.
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6
bin/calc
Executable file
6
bin/calc
Executable file
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#!/usr/bin/env php
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<?php
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require_once __DIR__."/../vendor/autoload.php";
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NoccyLabs\PhpCalc\Calculator::main();
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26
composer.json
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26
composer.json
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{
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"name": "noccylabs/php-calc",
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"description": "The calculator you never knew you needed",
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"type": "application",
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"license": "GPL-3.0-or-later",
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"autoload": {
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"psr-4": {
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"NoccyLabs\\PhpCalc\\": "src/"
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}
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},
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"authors": [
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{
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"name": "Christopher Vagnetoft",
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"email": "cvagnetoft@gmail.com"
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}
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],
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"require": {},
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"bin": [
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"bin/calc"
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],
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"extra": {
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"phar": {
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"output": "calc.phar"
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}
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}
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}
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294
src/Calculator.php
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294
src/Calculator.php
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<?php
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namespace NoccyLabs\PhpCalc;
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/**
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* "Yo dawg, we heard u like calculators, so we added a calculator to your fancy calculator"
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*
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* This is a fully sandboxed calculator that can be used to resolve fairly complex mathematical
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* expressions to a result. It handles paranthesis, mathematical functions and the most common
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* operations.
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*
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* It should in theory be safe to throw user-provided input to the evaluate() method, as the
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* functions are checked against a whitelist, and all evaluation is done virtually. It is at
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* least safer than eval(), and simpler than f.ex. ExpressionLanguage if all you need is math!
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*
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* @license GPL V3 or later
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* @copyright (c) 2022, NoccyLabs
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*/
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class Calculator
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{
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private $vars = [];
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private $consts = [];
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public function __construct()
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{
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$this->consts['pi'] = pi();
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}
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public function run()
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{
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while (true) {
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$in = readline("\001\e[92m\002~\001\e[0m\002 ");
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if (trim($in) === '') continue;
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readline_add_history(trim($in));
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try {
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$ret = $this->evaluate($in);
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$this->printResult($ret, true);
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} catch (\Throwable $t) {
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printf("\e[33;1m %s\e[0m\n", $t->getMessage());
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}
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}
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}
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public function printResult($ret, bool $color=false)
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{
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if ($ret !== null) {
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$_p = $this->vars['_p']??null;
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if (ctype_digit($_p)) {
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$out = sprintf("%.{$_p}f", $ret);
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} else {
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$out = $ret;
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}
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echo $color ? " \e[92;1m{$out}\e[0m\n" : "{$out}\n";
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} else {
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echo $color ? " \e[90m#null\e[0m\n" : "#null\n";
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}
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}
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/**
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* Evaluate a string and return the result.
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*
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* @param string The expression
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* @return int|float|null The result
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*/
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public function evaluate(string $expr)
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{
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$toks = $this->parse($expr);
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if (!count($toks)) return;
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$tokens = new TokenList($toks);
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$ret = $this->evalTokens($tokens);
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return $ret;
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}
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/**
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* Call a built-in math function
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*
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* @param string The function name
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* @param int|float Parameter value
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*/
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private function evalFunc(string $func, $val)
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{
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if (in_array($func, [
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'abs', 'acos', 'acosh', 'asin', 'asinh',
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'atan', 'atanh', 'ceil', 'cos', 'cosh',
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'floor', 'sin', 'sinh', 'log', 'round',
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'sqrt', 'tan', 'tanh'
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])) {
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return call_user_func($func, $val);
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}
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throw new \RuntimeException("Bad function {$func}");
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}
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/**
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* Recursively evaluate parsed tokens.
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*
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* Functions and paranthesized statements will be replaced by recursive calls t
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* evalTokens or evalFunc.
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*
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* @param TokenList The tokens to evaluate
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* @return int|float|null The result
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*/
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private function evalTokens(TokenList $toks)
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{
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$buf = [];
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$assign = null;
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while (($tok = $toks->read()) !== null) {
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if (str_ends_with($tok, '(')) {
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$val = $this->evalTokens($toks);
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$fn = rtrim($tok, '(');
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if ($fn) {
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//printf("feval : %s(%f)\n", $fn, $val);
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$val = $this->evalFunc($fn, $val);
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}
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array_push($buf, $val);
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} elseif ($tok == ')') {
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break;
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} elseif ($tok == ';') {
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if (!$assign) {
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//fprintf(STDERR, "warning: Use of semicolon without assignment\n");
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}
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$val = $this->flatten($buf);
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if ($assign) {
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//printf("store : %s←%f\n", $assign, $val);
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$this->vars[$assign] = $val;
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$assign = null;
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}
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$buf = [];
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} elseif ($tok == '=') {
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$assign = array_pop($buf);
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// printf("assign : %s (buf: %s)\n", $assign, join(" ", $buf));
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} else {
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if (array_key_exists($tok, $this->consts)) {
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$tok = $this->consts[$tok];
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} elseif (array_key_exists($tok, $this->vars)) {
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//printf("subst : %s→%f\n", $tok, $this->vars[$tok]);
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$tok = $this->vars[$tok];
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}
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array_push($buf, $tok);
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}
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}
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$ret = $this->flatten($buf);
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if ($assign) {
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//printf("%s=%f", $assign, $ret);
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$this->vars[$assign] = $ret;
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}
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return $ret;
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}
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/**
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* Takes a buffer and performs the requested operations on it until a single value remains.
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*
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* @param array The buffer of tokens to evaluate
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* @return int|float|null
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*/
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private function flatten(array $buf)
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{
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$sta = $buf;
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$out = [];
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if (count($buf) == 1) {
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return array_shift($buf);
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}
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//printf("flatten: %s\n", join(' ', $sta));
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for ($p = 0; $p < count($sta); $p++) {
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$t = $sta[$p];
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switch ($t) {
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case '^':
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$a = array_pop($out); $b = $sta[++$p];
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$t = pow($a, $b);
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break;
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}
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array_push($out, $t);
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}
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//if ($sta != $buf) printf(" : %s\n", join(' ', $sta));
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$sta = $out;
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$out = [];
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if (count($sta) == 1) {
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return array_shift($sta);
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}
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for ($p = 0; $p < count($sta); $p++) {
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$t = $sta[$p];
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switch ($t) {
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case '*':
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$a = array_pop($out); $b = $sta[++$p];
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$t = $a * $b;
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break;
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case '/':
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$a = array_pop($out); $b = $sta[++$p];
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$t = $a / $b;
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break;
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}
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array_push($out, $t);
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}
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//if ($sta != $buf) printf(" : %s\n", join(' ', $sta));
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$sta = $out;
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$out = [];
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if (count($sta) == 1) {
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return array_shift($sta);
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}
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for ($p = 0; $p < count($sta); $p++) {
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$t = $sta[$p];
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switch ($t) {
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case '+':
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$a = array_pop($out); $b = $sta[++$p];
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$t = $a + $b;
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break;
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case '-':
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$a = array_pop($out); $b = $sta[++$p];
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$t = $a - $b;
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break;
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}
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array_push($out, $t);
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}
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//if ($sta != $buf) printf(" : %s\n", join(' ', $sta));
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$sta = $out;
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$out = [];
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if (count($sta) > 1) {
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fprintf(STDERR, "warning: Buffer not empty after flattening, check your expression (contents: %s)\n", join(" ", $sta));
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}
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return array_shift($sta);
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}
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/**
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* Parse an input expression using regular expressions.
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*
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* Each supported token has its own regex patten.
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*
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* @param string The expression to parse
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* @return array The parsed tokens
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*/
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public function parse(string $expr): array
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{
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$expr = trim($expr);
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$src = $expr;
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$toks = [];
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while (preg_match('/^('.
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'[a-z]+\('. // sin(
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'|[a-z_]+'. // my_var
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'|\('. // (
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'|\)'. // )
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'|(-)?\d+\.\d+'. // 3.14
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'|(-)?\d+'. // 42
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'|='. // =
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'|[\+\-\*\/\^]'. // + - * / ^
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'|\;'. // ;
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')/', $expr, $m)) {
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$toks[] = $m[0];
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$expr = trim(substr($expr, strlen($m[0])));
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}
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if (strlen($expr) > 0) {
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printf("err: %s\n %s\n", $src, str_repeat(" ",strlen($src)-strlen($expr))."^");
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return [];
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}
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return $toks;
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}
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public static function main()
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{
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// call on run() or evaluate()
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$calc = new Calculator();
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$args = array_slice($GLOBALS['argv'], 1);
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if (count($args) > 0) {
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try {
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$ret = $calc->evaluate($args[0]);
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$calc->printResult($ret);
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} catch (\Throwable $t) {
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fprintf(STDERR, "error: %s\n", $t->getMessage());
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}
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} else {
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$calc->run();
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}
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}
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}
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42
src/TokenList.php
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42
src/TokenList.php
Normal file
@ -0,0 +1,42 @@
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<?php
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namespace NoccyLabs\PhpCalc;
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/**
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* Helper class to iterate over a list of tokens
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*
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* @license GPL V3 or later
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* @copyright (c) 2022, NoccyLabs
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*/
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class TokenList
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{
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private array $toks;
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private int $ptr = 0;
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public function __construct(array $toks)
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{
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$this->toks = $toks;
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}
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public function current(): ?string
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{
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return ($this->ptr >= count($this->toks) ? null : $this->toks[$this->ptr]);
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}
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public function read(): ?string
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{
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$v = $this->current();
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$this->next();
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return $v;
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}
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public function next(): ?string
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{
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if ($this->ptr < count($this->toks)) {
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$this->ptr++;
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return ($this->ptr < count($this->toks) ? $this->toks[$this->ptr] : null);
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}
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return null;
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}
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}
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Block a user