Canon Camera, Hackers Manual

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5.4 Lua primer
93
5.4.2 Strings
Strings are enclosed in single ( ‘...’ ) or double ( “...” ) quotes, or in dou-
bled square brackets ( [[...]] ). With this latter form, it is possible to define
strings that stretch across multiple lines. Strings can contain most of the
escape sequences used in other programming languages such as C or Java:
\f for a form feed, \n for a new line, \r for the carriage return. Strings can
be concatenated with the .. operator:
"CH"..
'
DK'
5.4.3 Tables
Tables are a core concept in Lua . Tables can contain an arbitrary number of
elements—numbers, strings, functions, and other tables.
Table definitions are enclosed in curly brackets ( {} ). Anything (except
nil ) can be a table element. Table elements can be addressed through the
element index. For instance:
disp_table = {'info', ' no_info ' ,
' off ' , ' electronic_viewfinder ' }
print(disp_table[2])
would print ‘no_info’ because indexing starts at 1. The number of table ele-
ments can be obtained through the operator
# :
print(#disp_table)
would print ‘4’.
Alternatively, table elements can be associated with explicit keys, in
which case the table works as a dictionary:
reverse_disp_table = {info = 0,
no_info = 1, off = 2,
electronic_viewfinder = 3}
In this case we could address the elements by their key:
print(reverse_disp_table["info"])
would print ‘0’. The following dot notation is also possible:
print(reverse_disp_table.info])