fullContextMatch (KFCM)

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()