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universe.py 22.2 KB
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from som.interpreter.interpreter import Interpreter
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from som.interpreter.bytecodes   import Bytecodes 
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from som.vm.symbol_table         import SymbolTable
from som.vmobjects.object        import Object
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from som.vmobjects.clazz         import Class
from som.vmobjects.array         import Array
from som.vmobjects.symbol        import Symbol
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from som.vmobjects.method        import Method
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from som.vmobjects.integer       import Integer
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from som.vmobjects.string        import String
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from som.vmobjects.block         import Block, block_evaluation_primitive
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from som.vmobjects.frame         import Frame
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from som.vmobjects.biginteger    import BigInteger
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from som.vmobjects.double        import Double
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from som.vm.shell import Shell

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import som.compiler.sourcecode_compiler as sourcecode_compiler

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import os
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from rlib.exit  import Exit
from rlib.osext import path_split
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class Universe(object):
    
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    def __init__(self, avoid_exit = False):
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        self._interpreter    = Interpreter(self)
        self._symbol_table   = SymbolTable()
        
        self._globals        = {}
        
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        self.nilObject      = None
        self.trueObject     = None
        self.falseObject    = None
        self.objectClass    = None
        self.classClass     = None
        self.metaclassClass = None
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        self.nilClass       = None
        self.integerClass   = None
        self.bigintegerClass= None
        self.arrayClass     = None
        self.methodClass    = None
        self.symbolClass    = None
        self.frameClass     = None
        self.primitiveClass = None
        self.systemClass    = None
        self.blockClass     = None
        self.stringClass    = None
        self.doubleClass    = None
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        self._last_exit_code = 0
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        self._avoid_exit     = avoid_exit
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        self._dump_bytecodes = False
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        self.classpath       = None
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    def exit(self, error_code):
        if self._avoid_exit:
            self._last_exit_code = error_code
        else:
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            raise Exit(error_code)
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    def last_exit_code(self):
        return self._last_exit_code
    
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    def get_interpreter(self):
        return self._interpreter
    
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    def execute_method(self, class_name, selector):
        self._initialize_object_system()

        clazz = self.load_class(self.symbol_for(class_name))

        # Lookup the invokable on class
        invokable = clazz.get_class().lookup_invokable(self.symbol_for(selector))

        bootstrap_method = self._create_bootstrap_method()
        bootstrap_frame  = self._create_bootstrap_frame(bootstrap_method, clazz)
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        return self.start(bootstrap_frame, invokable)
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    def _create_bootstrap_method(self):
        # Create a fake bootstrap method to simplify later frame traversal
        bootstrap_method = self.new_method(self.symbol_for("bootstrap"), 1, 0)
        bootstrap_method.set_bytecode(0, Bytecodes.halt)
        bootstrap_method.set_number_of_locals(self.new_integer(0))
        bootstrap_method.set_maximum_number_of_stack_elements(self.new_integer(2))
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        bootstrap_method.set_holder(self.systemClass)
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        return bootstrap_method
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    def _create_bootstrap_frame(self, bootstrap_method, receiver, arguments = None):
        # Create a fake bootstrap frame with the system object on the stack
        bootstrap_frame = self._interpreter.push_new_frame(bootstrap_method)
        bootstrap_frame.push(receiver)
        
        if arguments:
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            bootstrap_frame.push(arguments)
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        return bootstrap_frame
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    def interpret(self, arguments):
        # Check for command line switches
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        arguments = self.handle_arguments(arguments)
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        # Initialize the known universe
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        system_object = self._initialize_object_system()
        bootstrap_method = self._create_bootstrap_method()
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        # Start the shell if no filename is given
        if len(arguments) == 0:
            shell = Shell(self, self._interpreter)
            shell.set_bootstrap_method(bootstrap_method)
            shell.start()
            return
        else:
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            # Convert the arguments into an array
            arguments_array = self.new_array_with_strings(arguments)
            bootstrap_frame = self._create_bootstrap_frame(bootstrap_method, system_object, arguments_array)
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            # Lookup the initialize invokable on the system class
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            initialize = self.systemClass.lookup_invokable(self.symbol_for("initialize:"))
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            self.start(bootstrap_frame, initialize)
    
    def start(self, bootstrap_frame, invokable):
        # Invoke the initialize invokable
        invokable.invoke(bootstrap_frame, self._interpreter)

        # Start the interpreter
        return self._interpreter.start()
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    def handle_arguments(self, arguments):
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        got_classpath  = False
        remaining_args = []

        i = 0
        while i < len(arguments):
            if arguments[i] == "-cp":
                if i + 1 >= len(arguments):
                    self._print_usage_and_exit()
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                self.setup_classpath(arguments[i + 1])
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                i += 1    # skip class path
                got_classpath = True
            elif arguments[i] == "-d":
                self._dump_bytecodes = True
            else:
                remaining_args.append(arguments[i])
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            i += 1
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        if not got_classpath:
            # Get the default class path of the appropriate size
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            self.classpath = self._setup_default_classpath()
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        # check remaining args for class paths, and strip file extension
        i = 0
        while i < len(remaining_args):
            split = self._get_path_class_ext(remaining_args[i])

            if split[0] != "":  # there was a path
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                self.classpath.insert(0, split[0])
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            remaining_args[i] = split[1]
            i += 1
        
        return remaining_args
    
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    def setup_classpath(self, cp):
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        self.classpath = cp.split(os.pathsep)
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    def _setup_default_classpath(self):
        return ['.']
    
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    # take argument of the form "../foo/Test.som" and return
    # "../foo", "Test", "som"
    def _get_path_class_ext(self, path):
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        return path_split(path)
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    def _print_usage_and_exit(self):
        # Print the usage
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        std_println("Usage: som [-options] [args...]                          ")
        std_println("                                                         ")
        std_println("where options include:                                   ")
        std_println("    -cp <directories separated by " + os.pathsep     + ">")
        std_println("                  set search path for application classes")
        std_println("    -d            enable disassembling")
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        # Exit
        self.exit(0)
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    def _initialize_object_system(self):
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        # Allocate the nil object
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        self.nilObject = Object(None)
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        # Allocate the Metaclass classes
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        self.metaclassClass = self.new_metaclass_class()
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        # Allocate the rest of the system classes
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        self.objectClass     = self.new_system_class()
        self.nilClass        = self.new_system_class()
        self.classClass      = self.new_system_class()
        self.arrayClass      = self.new_system_class()
        self.symbolClass     = self.new_system_class()
        self.methodClass     = self.new_system_class()
        self.integerClass    = self.new_system_class()
        self.bigintegerClass = self.new_system_class()
        self.frameClass      = self.new_system_class()
        self.primitiveClass  = self.new_system_class()
        self.stringClass     = self.new_system_class()
        self.doubleClass     = self.new_system_class()
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        # Setup the class reference for the nil object
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        self.nilObject.set_class(self.nilClass)
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        # Initialize the system classes
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        self._initialize_system_class(self.objectClass,                 None, "Object")
        self._initialize_system_class(self.classClass,      self.objectClass, "Class")
        self._initialize_system_class(self.metaclassClass,   self.classClass, "Metaclass")
        self._initialize_system_class(self.nilClass,        self.objectClass, "Nil")
        self._initialize_system_class(self.arrayClass,      self.objectClass, "Array")
        self._initialize_system_class(self.methodClass,      self.arrayClass, "Method")
        self._initialize_system_class(self.symbolClass,     self.objectClass, "Symbol")
        self._initialize_system_class(self.integerClass,    self.objectClass, "Integer")
        self._initialize_system_class(self.bigintegerClass, self.objectClass, "BigInteger")
        self._initialize_system_class(self.frameClass,       self.arrayClass, "Frame")
        self._initialize_system_class(self.primitiveClass,  self.objectClass, "Primitive")
        self._initialize_system_class(self.stringClass,     self.objectClass, "String")
        self._initialize_system_class(self.doubleClass,     self.objectClass, "Double")
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        # Load methods and fields into the system classes
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        self._load_system_class(self.objectClass)
        self._load_system_class(self.classClass)
        self._load_system_class(self.metaclassClass)
        self._load_system_class(self.nilClass)
        self._load_system_class(self.arrayClass)
        self._load_system_class(self.methodClass)
        self._load_system_class(self.symbolClass)
        self._load_system_class(self.integerClass)
        self._load_system_class(self.bigintegerClass)
        self._load_system_class(self.frameClass)
        self._load_system_class(self.primitiveClass)
        self._load_system_class(self.stringClass)
        self._load_system_class(self.doubleClass)
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        # Load the generic block class
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        self.blockClass = self.load_class(self.symbol_for("Block"))
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        # Setup the true and false objects
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        self.trueObject  = self.new_instance(self.load_class(self.symbol_for("True")))
        self.falseObject = self.new_instance(self.load_class(self.symbol_for("False")))
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        # Load the system class and create an instance of it
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        self.systemClass = self.load_class(self.symbol_for("System"))
        system_object = self.new_instance(self.systemClass)
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        # Put special objects and classes into the dictionary of globals
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        self.set_global(self.symbol_for("nil"),    self.nilObject)
        self.set_global(self.symbol_for("true"),   self.trueObject)
        self.set_global(self.symbol_for("false"),  self.falseObject)
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        self.set_global(self.symbol_for("system"), system_object)
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        self.set_global(self.symbol_for("System"), self.systemClass)
        self.set_global(self.symbol_for("Block"),  self.blockClass)
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        return system_object
    
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    def symbol_for(self, string):
        # Lookup the symbol in the symbol table
        result = self._symbol_table.lookup(string)
        if result:
            return result
        
        # Create a new symbol and return it
        result = self.new_symbol(string)
        return result
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    def new_array_with_length(self, length):
        # Allocate a new array and set its class to be the array class
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        result = Array(self.nilObject)
        result.set_class(self.arrayClass)
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        # Set the number of indexable fields to the given value (length)
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        result.set_number_of_indexable_fields_and_clear(length, self.nilObject)
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        # Return the freshly allocated array
        return result
  
    def new_array_from_list(self, values):
        # Allocate a new array with the same length as the list
        result = self.new_array_with_length(len(values))

        # Copy all elements from the list into the array
        for i in range(len(values)):
            result.set_indexable_field(i, values[i])
    
        # Return the allocated and initialized array
        return result
  
    def new_array_with_strings(self, strings):
        # Allocate a new array with the same length as the string array
        result = self.new_array_with_length(len(strings))

        # Copy all elements from the string array into the array
        for i in range(len(strings)):
            result.set_indexable_field(i, self.new_string(strings[i]))
    
        # Return the allocated and initialized array
        return result
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    def new_block(self, method, context_frame, arguments):
        # Allocate a new block and set its class to be the block class
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        result = Block(self.nilObject)
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        result.set_class(self._get_block_class(arguments))

        # Set the method and context of block
        result.set_method(method)
        result.set_context(context_frame)

        # Return the freshly allocated block
        return result

    def new_class(self, class_class):
        # Allocate a new class and set its class to be the given class class
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        result = Class(self, class_class.get_number_of_instance_fields())
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        result.set_class(class_class)

        # Return the freshly allocated class
        return result

    def new_frame(self, previous_frame, method):
        # Allocate a new frame and set its class to be the frame class
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        result = Frame(self.nilObject)
        result.set_class(self.frameClass)
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        # Compute the maximum number of stack locations (including arguments,
        # locals and extra buffer to support doesNotUnderstand) and set the
        # number of indexable fields accordingly
        length = (method.get_number_of_arguments() +
                  method.get_number_of_locals().get_embedded_integer() +
                  method.get_maximum_number_of_stack_elements().get_embedded_integer() + 2)
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        result.set_number_of_indexable_fields_and_clear(length, self.nilObject)
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        # Set the method of the frame and the previous frame
        result.set_method(method)
        if previous_frame:
            result.set_previous_frame(previous_frame)

        # Reset the stack pointer and the bytecode index
        result.reset_stack_pointer()
        result.set_bytecode_index(0)

        # Return the freshly allocated frame
        return result

    def new_method(self, signature, num_bytecodes, num_literals):
        # Allocate a new method and set its class to be the method class
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        result = Method(self.nilObject)
        result.set_class(self.methodClass)
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        # Set the signature and the number of bytecodes
        result.set_signature(signature)
        result.set_number_of_bytecodes(num_bytecodes)
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        result.set_number_of_indexable_fields_and_clear(num_literals, self.nilObject)
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        # Return the freshly allocated method
        return result

    def new_instance(self, instance_class):
        # Allocate a new instance and set its class to be the given class
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        result = Object(self.nilObject, instance_class.get_number_of_instance_fields())
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        result.set_class(instance_class)
 
        # Return the freshly allocated instance
        return result

 
    def new_integer(self, value):
        # Allocate a new integer and set its class to be the integer class
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        result = Integer(self.nilObject)
        result.set_class(self.integerClass)
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        # Set the embedded integer of the newly allocated integer
        result.set_embedded_integer(value)
     
        # Return the freshly allocated integer
        return result
 
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    def new_biginteger(self, value):
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        # Allocate a new integer and set its class to be the integer class
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        result = BigInteger(self.nilObject)
        result.set_class(self.bigintegerClass)
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        # Set the embedded integer of the newly allocated integer
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        result.set_embedded_biginteger(value)
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        # Return the freshly allocated integer
        return result
 
 
    def new_double(self, value):
        # Allocate a new integer and set its class to be the double class
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        result = Double(self.nilObject)
        result.set_class(self.doubleClass)
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        # Set the embedded double of the newly allocated double
        result.set_embedded_double(value)
 
        # Return the freshly allocated double
        return result
    
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    def new_metaclass_class(self):
        # Allocate the metaclass classes
        result = Class(self)
        result.set_class(Class(self))

        # Setup the metaclass hierarchy
        result.get_class().set_class(result)

        # Return the freshly allocated metaclass class
        return result
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    def new_string(self, embedded_string):
        # Allocate a new string and set its class to be the string class
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        result = String(self.nilObject)
        result.set_class(self.stringClass)
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        # Put the embedded string into the new string
        result.set_embedded_string(embedded_string)
 
        # Return the freshly allocated string
        return result
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    def new_symbol(self, string):
        # Allocate a new symbol and set its class to be the symbol class
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        result = Symbol(self.nilObject)
        result.set_class(self.symbolClass)
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        # Put the string into the symbol
        result.set_string(string)

        # Insert the new symbol into the symbol table
        self._symbol_table.insert(result)

        # Return the freshly allocated symbol
        return result
      
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    def new_system_class(self):
        # Allocate the new system class
        system_class = Class(self)

        # Setup the metaclass hierarchy
        system_class.set_class(Class(self))
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        system_class.get_class().set_class(self.metaclassClass)
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        # Return the freshly allocated system class
        return system_class
    
    def _initialize_system_class(self, system_class, super_class, name):
        # Initialize the superclass hierarchy
        if super_class:
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            system_class.set_super_class(super_class)
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            system_class.get_class().set_super_class(super_class.get_class())
        else:
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            system_class.get_class().set_super_class(self.classClass)
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        # Initialize the array of instance fields
        system_class.set_instance_fields(self.new_array_with_length(0))
        system_class.get_class().set_instance_fields(self.new_array_with_length(0))

        # Initialize the array of instance invokables
        system_class.set_instance_invokables(self.new_array_with_length(0))
        system_class.get_class().set_instance_invokables(self.new_array_with_length(0))

        # Initialize the name of the system class
        system_class.set_name(self.symbol_for(name))
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        system_class.get_class().set_name(self.symbol_for(name + " class"))
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        # Insert the system class into the dictionary of globals
        self.set_global(system_class.get_name(), system_class)
    
    
    def get_global(self, name):
        # Return the global with the given name if it's in the dictionary of globals
        if self.has_global(name):
            return self._globals[name]

        # Global not found
        return None

    def set_global(self, name, value):
        # Insert the given value into the dictionary of globals
        self._globals[name] = value
  

    def has_global(self, name):
        # Returns if the universe has a value for the global of the given name
        return name in self._globals
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    def _get_block_class(self, number_of_arguments = None):
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        if not number_of_arguments:
            # Get the generic block class
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            return self.blockClass
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        # Compute the name of the block class with the given number of
        # arguments
        name = self.symbol_for("Block" + str(number_of_arguments))

        # Lookup the specific block class in the dictionary of globals and
        # return it
        if self.has_global(name):
            return self.get_global(name)

        # Get the block class for blocks with the given number of arguments
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        result = self._load_class(name, None)
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        # Add the appropriate value primitive to the block class
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        result.add_instance_primitive(block_evaluation_primitive(number_of_arguments, self))
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        # Insert the block class into the dictionary of globals
        self.set_global(name, result)

        # Return the loaded block class
        return result

    def load_class(self, name):
        # Check if the requested class is already in the dictionary of globals
        if self.has_global(name):
            return self.get_global(name)

        # Load the class
        result = self._load_class(name, None)

        # Load primitives (if necessary) and return the resulting class
        if result and result.has_primitives():
            result.load_primitives()
    
        return result

    def _load_system_class(self, system_class):
        # Load the system class
        result = self._load_class(system_class.get_name(), system_class)

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        if not result:
            error_println(system_class.get_name().get_string()
                   + " class could not be loaded. It is likely that the "
                   + " class path has not been initialized properly. "
                   + "Please make sure that the '-cp' parameter is given on the command-line.")
            self.exit(200)

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        # Load primitives if necessary
        if result.has_primitives():
            result.load_primitives()

    def _load_class(self, name, system_class):
        # Try loading the class from all different paths
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        for cpEntry in self.classpath:
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            try:
                # Load the class from a file and return the loaded class
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                result = sourcecode_compiler.compile_class_from_file(cpEntry, name.get_string(), system_class, self)
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                if self._dump_bytecodes:
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                    from som.compiler.disassembler import dump
                    dump(result.get_class())
                    dump(result)
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                return result
            except IOError:
                # Continue trying different paths
                pass

        # The class could not be found.
        return None
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    def load_shell_class(self, stmt):
        # Load the class from a stream and return the loaded class
        result = sourcecode_compiler.compile_class_from_string(stmt, None, self)
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        if self._dump_bytecodes:
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            from som.compiler.disassembler import dump
            dump(result)
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        return result

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def error_print(msg):
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    os.write(2, msg)
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def error_println(msg = ""):
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    os.write(2, msg + "\n")
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def std_print(msg):
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    print msg,
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def std_println(msg=""):
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    print msg

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def main(args):
    u = Universe()
    u.interpret(args[1:])
    u.exit(0)

if __name__ == '__main__':
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    import sys
    try:
        main(sys.argv)
    except Exit as e:
        sys.exit(e.code)