Step 6: Stores, any(), and index()
When we have many similar rules, as in the last example on the previous page, we can group them together into one rule by using
stores. A store is a set of characters that are grouped under a single name. Stores are used in rules with the any() and index() statements. We create a store with a store() statement:
store(vowels) "aeiou"
This creates a store called vowels, which contains the five lowercase vowels. Note that we could also have written the
content of the store using ANSI or Unicode character codes, in the same way as the output.
The any() statement is used to match a character from a specific store. For example, the following rule will
replace any vowel with a period, when used with the store above:
+ any(vowels) > "."
The any() statement can be used in the context or in the key part of a rule. It cannot be used in the
output.
The second statement that is used with stores is the index() statement. It is usually used in the output of
a rule, and will output the character from a particular store at the same position as the character matched by a specified
any() statement. This is best shown with an example; this rule will convert all input to uppercase:
store(lowercase) "abcdefghijklmnopqrstuvwxyz"
store(uppercase) "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+ any(lowercase) > index(uppercase,1)
When a letter, such as j is typed, the any() statement finds its position in the
lowercase store; the index() statement then gets this index from the any()
statement, and outputs the character at the same position in the uppercase store, in this case J.
The index() statement has two parts: the store from which it takes the output character, and the offset of
the any() statement that it gets the character position from. This offset is found by counting the characters and
statements in the context and key parts of the rule up to the any() statement. Again, a few examples may help to
illustrate this:
"a" + any(somestore) > index(otherstore,2) c The 'any' statement
c is character #2
"ab" any(somestore) + "c" > index(otherstore,3) c The 'any' statement
c is character #3
c Here the 'index' statement references the second 'any' statement used,
c which is character #4
U+0041 any(somestore) "B" + any(otherstore) > index(thirdstore,4)
c You can have multiple 'index' statements in the output, which can
c reference the same or different 'any's
any(store1) + any(store2) > index(store1,2) index(store2,1) index(store3,2)
Using stores in the Quick French keyboard
We can now reduce the number of rules needed for the Quick French keyboard by using stores. We will make five stores: one for the
unaccented vowels, and one each for vowels with acute accents, grave accents, circumflexes, and diereses. For clarity, the
group() statement is repeated below:
group(Main) using keys
store( plainvowels ) 'a' 'e' 'i' 'o' 'u' 'A' 'E' 'I' 'O' 'U'
store( acutevowels ) U+00E1 U+00E9 U+00ED U+00F3 U+00FA U+00C1 U+00C9 U+00CD U+00D3 U+00DA
store( gravevowels ) U+00E0 U+00E8 U+00EC U+00F2 U+00F9 U+00C0 U+00C8 U+00CC U+00D2 U+00D9
store( circumvowels ) U+00E2 U+00EA U+00EE U+00F4 U+00FB U+00C2 U+00CA U+00CE U+00D4 U+00DB
store( dresisvowels ) U+00E4 U+00EB U+00EF U+00F6 U+00FC U+00C4 U+00CB U+00CF U+00D6 U+00DC
"'" + any( plainvowels ) > index( acutevowels, 2 )
"`" + any( plainvowels ) > index( gravevowels, 2 )
"^" + any( plainvowels ) > index( circumvowels, 2 )
'"' + any( plainvowels ) > index( dresisvowels, 2 )
This is far clearer than the long list of rules that we used earlier. Obviously we should add one or two more ordinary rules to produce upper- and lower-case ç, ý, and also the angled quotes « and ». Then we will have almost finished the keyboard:
"'" + "y" > U+00FD c Acute-accented Y
"'" + "Y" > U+00DD
"'" + "c" > U+00E7 c C-cedilla
"'" + "C" > U+00C7
"<" + "<" > U+00AB c Angled quotes
">" + ">" > U+00BB
All we need to do now is to test the keyboard.
