SUMMARY: MODULE | CLASS | TYPE | PROC | VAR | CONST | DETAIL: TYPE | PROC | VAR | CONST |
This module is a reimplementation of the Python dictionary code in Oberon-2. It is based on version 2.65 of the python file `src/Objects/dictobject.c'. It maps objects on other objects. Some bit twiddling is required, partially due to the algorithm and partially due to performance, which may impede portability of the code.
Differences between `dictobject.c' and this implementation:
NIL can be used as a value. This implies that the field `Entry.value' cannot be used to determine if the entry is in use or not.
Any inefficiencies in this implementation are my fault, and do not originate in the Python implementation.
ADT:Storable IO Object Object RT0
Class List | |
Dictionary |
Class Summary: Dictionary [Detail] | |
+---RT0.Object | +---Object.Object | +---ADT:Storable.Object | +--ADT:Dictionary:IntValue.Dictionary | |
Constructor Summary | |
Init(Dictionary) Initializes dict to an empty dictionary. | |
New(): Dictionary Creates a new, empty dictionary. | |
Method Summary | |
Clear() Removes all items from the dictionary dict. | |
Copy(): Dictionary Creates a copy of the dictionary dict. | |
Delete(Key) Removes the item with the key key from the dictionary dict. | |
Destroy() | |
Get(Key): Value Retrieves the value associated with key in the dictionary dict. | |
HasKey(Key): BOOLEAN Tests if an item in dict exists with the key key. | |
Keys(): ObjectArrayPtr Returns the list of keys of the dictionary dict. | |
Load(Reader) Loads data of dict from r. | |
Lookup(Key, VAR Value): BOOLEAN If key exists in the dictionary dict, then the procedure assigns the value of key to value and returns TRUE; otherwise, it returns FALSE and value is undefined. | |
Set(Key, Value) Sets the value for key key in the dictionary dict to value. | |
Size(): LONGINT Returns the number of items in the dictionary. | |
Store(Writer) Stores data of dict to w. | |
Inherited Methods | |
From RT0.Object: From Object.Object: From ADT:Storable.Object: |
Type Summary | |
[Entry] = RECORD ... END | |
[Hash] = LONGINT | |
[Index] = LONGINT | |
Key = Object | |
[Table] = POINTER TO ARRAY OF Entry | |
Value = LONGINT |
Class Detail: Dictionary |
Constructor Detail |
PROCEDURE Init(dict: Dictionary)
Initializes dict to an empty dictionary.
PROCEDURE New(): Dictionary
Creates a new, empty dictionary.
Method Detail |
PROCEDURE (dict: Dictionary) Clear()
Removes all items from the dictionary dict.
PROCEDURE (dict: Dictionary) Copy(): Dictionary
Creates a copy of the dictionary dict.
PROCEDURE (dict: Dictionary) Delete(key: Key)
Removes the item with the key key from the dictionary dict.
Pre-condition: n item with the key key exists in the dictionary dict. This implies that key is not NIL.
PROCEDURE (dict: Dictionary) Destroy()
PROCEDURE (dict: Dictionary) Get(key: Key): Value
Retrieves the value associated with key in the dictionary dict.
Pre-condition: An item with the key key exists in the dictionary dict. This implies that key is not NIL.
PROCEDURE (dict: Dictionary) HasKey(key: Key): BOOLEAN
Tests if an item in dict exists with the key key.
Pre-condition: key is not NIL.
PROCEDURE (dict: Dictionary) Keys(): ObjectArrayPtr
Returns the list of keys of the dictionary dict. The keys are listed in no particular order.
PROCEDURE (dict: Dictionary) Load(r: Reader) RAISES Error;
Loads data of dict from r. Nested record pointers are loaded by calling the type-bound procecdure Reader.ReadObject. This procedure must be symmetric to Object.Store, or data internalization will break, causing undefined object state or program termination.
Note: When internalizing a file with alien objects, it is possible that the type-bound procedure Object.Load is invoked more than once for a single object. Except for the results of the last call, all duplicates are discarded. Because of this, all changes by this procedure to any program state that is not part of the object dict are deprecated.
Pre-condition: This procedure is either activated by a super call, or from the procedure Reader.ReadObject.
[Description inherited from Load]
Redefines: Load
PROCEDURE (dict: Dictionary) Lookup(key: Key; VAR value: Value): BOOLEAN
If key exists in the dictionary dict, then the procedure assigns the value of key to value and returns TRUE; otherwise, it returns FALSE and value is undefined.
Pre-condition: key is not NIL.
PROCEDURE (dict: Dictionary) Set(key: Key; value: Value)
Sets the value for key key in the dictionary dict to value. If an item with this key already exists, its value is replaced. Otherwise, a new item is created with the given (key, value) pair.
Pre-condition: key is not NIL.
PROCEDURE (dict: Dictionary) Size(): LONGINT
Returns the number of items in the dictionary.
PROCEDURE (dict: Dictionary) Store(w: Writer) RAISES Error;
Stores data of dict to w. Nested record pointers are stored by calling the type-bound procedure Writer.WriteObject. The procedure is not allowed to make any changes to the global state of the program, except for calling the `Write' methods of the writer w. Any redefinition of this procedure must include a super call, preferably as the first statement of the procedure body.
Pre-condition: This procedure is either activated by a super call, or from the procedure Writer.WriteObject.
[Description inherited from Store]
Redefines: Store
Type Detail |
TYPE [Entry] = RECORD END
TYPE [Hash] = LONGINT
TYPE [Index] = LONGINT
TYPE Key = Object
TYPE [Table] = POINTER TO ARRAY OF Entry
TYPE Value = LONGINT