madlisp/lib.php

<?php

require_once('classes.php');

function ml_get_env(): MLEnv
{
    $env = new MLEnv();

    // logic

    $env->set('or', function (...$args) {
        // return first true
        for ($i = 0; $i < count($args) - 1; $i++) {
            if ($args[$i] == true) {
                return $args[$i];
            }
        }

        // return last
        return $args[count($args) - 1];
    });

    $env->set('and', function (...$args) {
        // return first false
        for ($i = 0; $i < count($args) - 1; $i++) {
            if ($args[$i] == false) {
                return $args[$i];
            }
        }

        // return last
        return $args[count($args) - 1];
    });

    $env->set('not', fn ($a) => !$a);

    // arithmetic

    $env->set('+', function (...$args) {
        return array_sum($args);
    });

    $env->set('-', function (...$args) {
        $result = $args[0] ?? null;
        for ($i = 1; $i < count($args); $i++) {
            $result -= $args[$i];
        }
        return $result;
    });

    $env->set('*', function (...$args) {
        $result = $args[0] ?? null;
        for ($i = 1; $i < count($args); $i++) {
            $result *= $args[$i];
        }
        return $result;
    });

    $env->set('/', function (...$args) {
        $result = $args[0] ?? null;
        for ($i = 1; $i < count($args); $i++) {
            $result /= $args[$i];
        }
        return $result;
    });

    $env->set('%', function (...$args) {
        $result = $args[0] ?? null;
        for ($i = 1; $i < count($args); $i++) {
            $result %= $args[$i];
        }
        return $result;
    });

    // comparison

    $env->set('=', fn ($a, $b) => $a == $b);
    $env->set('<', fn ($a, $b) => $a < $b);
    $env->set('>', fn ($a, $b) => $a > $b);
    $env->set('<=', fn ($a, $b) => $a <= $b);
    $env->set('>=', fn ($a, $b) => $a >= $b);
    $env->set('!=', fn ($a, $b) => $a != $b);

    // types

    $env->set('type?', function ($a) {
        if ($a instanceof Closure) {
            return 'function';
        } elseif ($a instanceof MLList) {
            return 'list';
        } elseif ($a instanceof MLHash) {
            return 'hash';
        } elseif ($a instanceof MLSymbol) {
            return 'symbol';
        } elseif ($a === true || $a === false) {
            return 'bool';
        } elseif ($a === null) {
            return 'null';
        } elseif (is_int($a)) {
            return 'int';
        } elseif (is_float($a)) {
            return 'float';
        } else {
            return 'string';
        }
    });

    $env->set('fn?', fn ($a) => $a instanceof Closure);
    $env->set('list?', fn ($a) => $a instanceof MLList);
    $env->set('hash?', fn ($a) => $a instanceof MLHash);
    $env->set('sym?', fn ($a) => $a instanceof MLSymbol);
    $env->set('bool?', fn ($a) => $a === true || $a === false);
    $env->set('true?', fn ($a) => $a == true); // not strict
    $env->set('false?', fn ($a) => $a == false); // not strict
    $env->set('null?', fn ($a) => $a === null);
    $env->set('int?', fn ($a) => is_int($a));
    $env->set('float?', fn ($a) => is_float($a));
    $env->set('str?', fn ($a) => is_string($a));

    // collections

    $env->set('list', function (...$args) {
        return new MLList($args);
    });

    $env->set('hash', function (...$args) {
        if (count($args) % 2 == 1) {
            throw new MadLispException('uneven number of arguments for hash');
        }

        $data = [];

        for ($i = 0; $i < count($args) - 1; $i += 2) {
            $key = $args[$i];
            $val = $args[$i + 1];

            if (!is_string($key)) {
                throw new MadLispException('invalid key for hash (not string)');
            }

            $data[$key] = $val;
        }

        return new MLHash($data);
    });

    // for debugging!
    $env->set('eval', fn ($a) => ml_eval($a, $env));

    return $env;
}