File: src/eMacros/Scope.php

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File: src/eMacros/Scope.php
Role: Class source
Content type: text/plain
Description: Class source
Class: eMacros
PHP LISP language interpreter
Author: By
Last change:
Date: 7 years ago
Size: 2,201 bytes
 

Contents

Class file image Download
<?php
namespace eMacros;

class
Scope implements \ArrayAccess, \IteratorAggregate {
   
/**
     * Symboil table
     * @var array
     */
   
public $symbols = array();
   
   
/**
     * Macros list
     * @var array
     */
   
public $macros = array();
       
    protected static function
symbol($symbol) {
        if (
$symbol instanceof Symbol) {
            return
$symbol->symbol;
        }
        elseif (
is_string($symbol)) {
            return
$symbol;
        }
       
        throw new \
UnexpectedValueException(sprintf("Unexpected value of type '%s'.", is_object($symbol) ? get_class($symbol) : gettype($symbol)));
    }
   
   
/**
     * Obtains a symbol from table
     * (non-PHPdoc)
     * @see ArrayAccess::offsetGet()
     */
   
public function offsetGet($symbol) {
       
$sym = self::symbol($symbol);

       
//is symbol defined on this scope?
       
if (array_key_exists($sym, $this->symbols)) {
            return
$this->symbols[$sym];
        }
        else {
            foreach (
$this->macros as $regex => $callback) {
                if (
preg_match($regex, $sym, $matches)) {
                   
$this->symbols[$sym] = $callback->__invoke($matches);
                    return
$this->symbols[$sym];
                }
            }
        }
       
        return
null;
    }
   
    public function
offsetExists($symbol) {
        return
true;
    }
   
   
/**
     * Stores a symbol
     * Used when setting up a Scope/Package
     * Ex: $this['.'] = new Concatenation();
     * (non-PHPdoc)
     * @see ArrayAccess::offsetSet()
     */
   
public function offsetSet($symbol, $value) {
       
$symbol = Symbol::validateSymbol($symbol);
       
$this->symbols[$symbol] = $value;
    }
   
   
/**
     * Removes a symbol from table
     * (non-PHPdoc)
     * @see ArrayAccess::offsetUnset()
     */
   
public function offsetUnset($symbol) {
        unset(
$this->symbols[$symbol]);
    }
   
   
/**
     * Obtains a symbol iterator
     * (non-PHPdoc)
     * @see IteratorAggregate::getIterator()
     */
   
public function getIterator() {
       
$symbols = array();
       
        foreach (
$this->listSymbols() as $name) {
           
$symbols[$name] = $this[$name];
        }
   
        return new \
ArrayIterator($symbols);
    }
   
   
/**
     * Obtains all defined symbols
     * @return array
     */
   
public function listSymbols() {
        return
array_keys($this->symbols);
    }
   
   
/**
     * Adds a new macro
     * @param string $regex
     * @param \Closure $handler
     */
   
public function macro($regex, \Closure $handler) {
       
$this->macros[$regex] = $handler;
    }
}
?>

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