Programmer's Guide - Stores
Stores are a method of grouping multiple characters together, in order to deal
with them all in a similar way. The most common use of stores is to reduce the
number of rules required in a keyboard by allowing a single rule to match
multiple characters through the use of stores and the any
statement. An
example of this is given in the tutorial.
System stores are stores with a name beginning with &, which have a special purpose, usually defining properties or behaviour of the keyboard.
Stores with only a single character are usually used to define named constants.
Creating Stores
Stores are created with the store
statement:
store( %storename% ) %storecontents%
Where storename
is an identifier you give to the store, and storecontents
is the store's contents, expressed as a string or a sequence of Unicode or ANSI
character constants. Virtual keys and deadkeys can also be used in stores.
All stores must be given unique identifiers, and are visible throughout the keyboard file. A store statement can be placed anywhere in a keyboard source file, and its visibility is unaffected.
Using Stores
Stores are most often used with the any
and index
keywords. The
any
keyword is used in the context or key section of the rule, and will
match any character in the specified store, remembering its index.
any( %store% )
The index
statement is used to look up a character in a store at the index
where a specified any
statement matched a character. The any
statement used to obtain the index is referenced by its position in the context
and key, a 1-based number.
index( %store%, %position% )
Note that an index
statement may reference an any
statement which
uses a different store: the only requirement is that the stores used by each have
the same length.
Example:
any(vowel) + '^' > index(vowel_circum, 1)
Outputting Stores
The outs
statement can be used to output the contents of a store. This
can be used in another store, or in the context or output of a rule.
outs( %storename% )
The IPAMenu.kmn
sample keyboard gives an example of the use of stores and
outs
to create a menu-based keyboard for entry of characters from the
International Phonetic Alphabet.