HASH(2)

NAME

hash, HashTable − hash table

SYNOPSIS

include "hash.m";
hash := load Hash Hash->PATH;
new: fn(size:int):ref HashTable;
HashTable: adt{
insert: fn(h:self ref HashTable, key:string, val:HashVal);
find: fn(h:self ref HashTable, key:string):ref HashVal;
delete: fn(h:self ref HashTable, key:string);
all: fn(h:self ref HashTable): list of HashNode;
};
HashVal: adt{
i: int;
r: real;
s: string;
};
HashNode: adt{
key: string;
val: ref HashVal;
};
fun1, fun2: fn(s:string, n:int):int;

DESCRIPTION

The hash module provides support for arrays that are indexed by keys of type string.

The values may be any combination of int, real, or string. New creates and returns a new HashTable with size slots. The hashing works best if size is a prime number. The HashVal adt contains the data values of the hash. The HashNode adt contains the key/value pair for each element in the table.

ht.insert(key, value)
Adds a new key/value pair to the table. If an element with the same key already exists, it will acquire the new value.

ht.find(key)
Search the table for an element with the given key and return the value found; return nil if none was found.

ht.delete(key)
Removes any element with the given key from the table.

ht.all()
Returns a list of all key/value pairs stored in the table.

Fun1 and fun2 provide access to two different string hashing functions. Fun1 is the function used internally; fun2 is the same as that used in the Limbo compiler. They each compute the hash value of s and return a value between 0 and n−1.

SOURCE

/appl/lib/hash.b

BUGS

HashVal should really be a pick.