fullContextMatch (KFCM)

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Summary

Context matching: Returns true if the current context matches the specified rule context specification.

Syntax

keyman.interface.fullContextMatch(n, Pelem, rule);

or

KeymanWeb.KFCM(n, Pelem, rule); // Shorthand

Parameters

n : Type: number : Relative position of the caret for the context match attempt.

Pelem : Type: Element : The element being operated upon.

rule : Type: Array(ContextEntry) : The rule context specification to be matched.

Return Value

boolean : true if the context matches the rule specification rule, otherwise false.

Rule specification

Each ContextEntry in the rule array must be one of the following six types:

• A plain string with one character

• A DeadkeyEntry object with the following members:

  t : 'd' : Indicates to expect a deadkey entry.

  d : number : The integer ID of the deadkey to match.

• An AnyEntry object with the following members:

  t : 'a' : Indicates the use of an any statement.

  a : string : The store string to be searched for a context match

  n : boolean optional : true signals to negate the match, as with a notany statement.

• An IndexEntry object with the following members:

  t : 'i' : Indicates the use of an index statement.

  i : string : the store string to be indexed for output corresponding to a previous any

  o : number : the index of the corresponding any in the rule's context, starting from 1.

• A ContextEx object with the following members:

  t : 'c' : Indicates the use of a context statement.

  c : number : The position in context to be matched by the current context location.

• A NulEntry object with the following member:

  t : 'n' : Indicates the use of a context-based nul rule.

The rule will be interpreted left to right, starting at the specified relative position to the caret.

Description

This is a core element of keyboard input management within KeymanWeb introduced with version 10.0, typically called automatically during keystroke processing events. For comparison with Developer 'rules' from keyboard source code...

store(pair_1) 'aA'
store(pair_2) 'bB'

c Lots of keyboard rules...

dk(money) 'c' any(pair_1) index(pair_2, 3) + '.' > 'taxi'

would have Javascript roughly as follows:

// In the keyboard store definitions:
this.s_pair_1 = 'aA';            // store(pair_1) 'aA'
this.s_pair_2 = 'bB';            // store(pair_2) 'bB'

// For the deadkey:
this.d_money = 0;                // dk(money)'s internal id

// Within the keyboard rule-matching function:
var matched = keyman.interface.fullContextMatch(4, element, {
  {t:'d', d:this.d_money},       // dk(money)
  'c',                           // 'c'
  {t:'a', a:this.s_pair_1},      // 'any(pair_1)'
  {t:'i', i:this.s_pair_2, o:3}  // 'index(pair_2, 3)'
});

See also

• The Keyman Keyboard Language Reference
• keyman.interface.contextMatch()
• keyman.interface.deleteContext()