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HASHSTASH(3) 3 (libbash hashstash library manual) HASHSTASH(3)

NAME

hashstash
libbash library that implements hash data structure

SYNOPSIS

⟨Value⟩ ⟨Key⟩ ⟨HashName⟩ [SubHashName [...]]
$retval hashGet
⟨Key⟩ ⟨HashName⟩ [SubHashName [...]]
$retval hashKeys
⟨HashName⟩ [SubHashName [...]]
⟨Key⟩ ⟨HashName⟩ [SubHashName [...]]
⟨HashName⟩ [SubHashName [...]]

DESCRIPTION

General

hashstash is a collection of functions that implement basic hash data-structure in bash scripting language.

The function list:

hashSet
Adds a value to the hash
hashGet
Returns a value from the hash
hashKeys
Returns a list of keys of the hash
hashRemove
Removes a key from the hash
hashDelete
Deletes a hash

Detailed interface description follows.

FUNCTIONS DESCRIPTIONS

hashSet ⟨Value⟩ ⟨Key⟩ ⟨Hashname⟩ [SubHashName [...]]

Adds a value to the hash.

Parameters:

Value
The value to set in HashName[Key].
Key
The key for the value Value.
HashName⟩ [SubHashName [...]]
A string that contains the name of the hash. If the hash is a sub hash of another hash, the "father hash" name MUST BE WRITTEN FIRST, followed by the sub-hash name.

Value will be the value of the key Key in the hash HashName. For example if you have (or want to define) hash C, which is subhash of hash B, which is subhash of hash A, and C has a key named ckey1 with value cval1, then you should use:

hashSet cval1 ckey1 A B C

$retval hashGet ⟨Key⟩ ⟨HashName⟩ [SubHashName [...]]

Returns the value of Key in HashName to the $retval variable.

Parameters:

Key
The key that hold the value we wish to get.
HashName⟩ [SubHashName [...]]
A string that contains the name of the hash. If the hash is a sub hash of another hash, the “father hash” name MUST BE WRITTEN FIRST, followed by the sub-hash name.

Return Value:

The value of the key Key in the hash HashName. The value is returned in the variable $retval.

$retval hashKeys ⟨HashName⟩ [SubHashName [...]]

Returns a list of keys of the hash HashName in the variable $retval.

Parameters:

HashName⟩ [SubHashName [...]]
A string that contains the name of the hash. If the hash is a sub hash of another hash, the “father hash” name MUST BE WRITTEN FIRST, followed by the sub-hash name.

Return Value:

The value of the key Key in the hash HashName. The value is returned in the variable $retval.

hashRemove ⟨Key⟩ ⟨HashName⟩ [SubHashName [...]]

Removes the key Key from the hash HashName.
Key
The key we wish to remove from HashName.
HashName⟩ [SubHashName [...]]
A string that contains the name of the hash. If the hash is a sub hash of another hash, the “father hash” name MUST BE WRITTEN FIRST, followed by the sub-hash name.

This function should also be used to remove a sub-hash from its “father hash”. In that case, the key will be the name of the sub-hash.

hashDelete ⟨HashName⟩ [SubHashName [...]]

Deletes the hash HashName [SubHashName [...]].

Parameters:

HashName⟩ [SubHashName [...]]
A string that contains the name of the hash. If the hash is a sub hash of another hash, the “father hash” name MUST BE WRITTEN FIRST, followed by the sub-hash name.

If this function is used on a sub-hash, a key with the name of the sub-hash will remain in its “father hash” and will hold a NULL value.

BUGS

A hash name can only contain characters that are valid as part of bash variable names (i.e. a-zA-Z0-9_). The same applies for hash keys.

As for now, there is no way of knowing if a key represents a value or a sub-hash. If a sub-hash will be used as a key, the returned value will be its keys list.

EXAMPLES

Define hash table hashA with key Akey1 with value Aval1 use:
% hashSet Aval1 Akey1 Ahash
Now:
% hashGet Akey1 Ahash
% echo $retval
Aval1
% hashKeys Ahash
% echo $retval
Akey1
%

HISTORY

The idea to write hashstash library appeared when we've discovered the full power of the bash eval function.

As of the name hashstash, it has two meanings. The first, it means ‘stash’ of hash functions. The second is, that hashstash contains subhashes inside, so it looks like stash of packed information.

AUTHORS

Hai Zaar ⟨haizaar@haizaar.com⟩
Gil Ran ⟨gil@ran4.net⟩

SEE ALSO

ldbash(1), libbash(1)
October 22, 2019 Linux