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Nasal scripting language: Difference between revisions
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→Variables
m (→Nasal Console) |
m (→Variables) |
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var z={}; # z is a local hash (dictionary or table) - also used for OOP | var z={}; # z is a local hash (dictionary or table) - also used for OOP | ||
</syntaxhighlight> | </syntaxhighlight> | ||
Now you may be wondering, what the heck is a vector, and what is a hash - and where's the difference? | |||
The difference is, elements in a vector are sequentially numbered, i.e. each element has a numeric index: | |||
<syntaxhighlight lang="php"> | |||
var my_vector = ['A','B','C']; | |||
</syntaxhighlight> | |||
This initializes a vector with three elements: A, B and C. | |||
Now, to access each element of the vector, you would need to use the element's numerical index: | |||
<syntaxhighlight lang="php"> | |||
var my_vector = ['A','B','C']; | |||
print (my_vector[0] ); #prints A | |||
print (my_vector[1] ); #prints B | |||
print (my_vector[2] ); #prints C | |||
</syntaxhighlight> | |||
As can be seen, indexing starts at 0. | |||
Compared to vectors, hashes don't use square brackets but curly braces instead: | |||
<syntaxhighlight lang="php"> | |||
var my_hash = {}; | |||
</syntaxhighlight> | |||
Now, hashes may not just have numerical indexes, but also symbolic indexes as lookup keys: | |||
<syntaxhighlight lang="php"> | |||
var my_hash = {first:'A',second:'B',third:'C'}; | |||
</syntaxhighlight> | |||
This will create a hash (imagine it like a storage container for a bunch of related variables) and initialize it with three values (A,B and C) which are assigned to three different lookup keys: first, second, third. | |||
In other words, you can access each element in the hash by using its lookup key: | |||
<syntaxhighlight lang="php"> | |||
var my_hash = {first:'A',second:'B',third:'C'}; | |||
print ( my_hash.first ); # will print A | |||
print ( my_hash.second ); # will print B | |||
print ( my_hash.third ); # will print C | |||
</syntaxhighlight> | |||
Nasal supports a "nil" value for use as a null pointer equivalent: | Nasal supports a "nil" value for use as a null pointer equivalent: | ||