Stores, 'any', and 'index'
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:
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 used only 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 number of the any statement that it gets the character position from. This number is found by counting the characters 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 d065 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.
|Rules with Context||Testing the Keyboard|