1 GENERAL ENCHANCEMENTS TO EXTENSION LOGIC :
5 exten => s,5,BackGround,blabla
7 The parameter (blabla) can be quoted ("blabla"). In this case, a
8 comma does not terminate the field.
10 Also, characters special to variable substitution, expression evaluation, etc
11 (see below), can be quoted. For example, to literally use a $ on the
12 string "$1231", quote it with a preceeding \. Special characters that must
13 be quoted to be used, are [ ] $ " \. (to write \ itself, use \\).
17 Parameter strings can include variables. Variable names are arbitrary strings.
18 They are stored in the respective channel structure.
20 To set a variable to a particular value, do :
22 ;exten => 1,2,SetVar,varname=value
24 You can substitute the value of a variable everywhere using ${variablename}.
25 For example, to stringwise append $lala to $blabla and store result in $koko,
28 ;exten => 1,2,SetVar,koko=${blabla}${lala}
30 There are also the following special variables:
33 ${CALLERIDNAME} Caller ID Name only
34 ${CALLERIDNUM} Caller ID Number only
35 ${EXTEN} Current extension
36 ${CONTEXT} Current context
37 ${PRIORITY} Current priority
38 ${CHANNEL} Current channel name
39 ${ENV(VAR)} Environmental variable VAR
40 ${EPOCH} Current unix style epoch
41 ${DATETIME} Current date time in the format: YYYY-MM-DD_HH:MM:SS
43 There are two reference modes - reference by value and reference by name.
44 To refer to a variable with its name (as an argument to a function that
45 requires a variable), just write the name. To refer to the variable's value,
46 enclose it inside ${}. For example, SetVar takes as the first argument
47 (before the =) a variable name, so:
49 ;exten => 1,2,SetVar,koko=lala
50 ;exten => 1,3,SetVar,${koko}=blabla
52 stores to the variable "koko" the value "lala" and to variable "lala" the
55 In fact, everything contained ${here} is just replaced with the value of
60 Everything contained inside a bracket pair prefixed by a $ (like $[this]) is
61 considered as an expression and it is evaluated. Evaluation works similar to
62 (but is done on a later stage than) variable substitution: the expression
63 (including the square brackets) is replaced by the result of the expression
64 evaluation. The arguments and operands of the expression MUST BE separated
65 with spaces (take care NOT to leave ANY spaces between opening and closing
66 square brackets and the first and last arguments).
68 For example, after the sequence:
70 exten => 1,1,SetVar,"lala=$[1 + 2]";
71 exten => 1,2,SetVar,"koko=$[2 * ${lala}]";
73 the value of variable koko is "6".
75 Operators are listed below in order of increasing precedence. Operators
76 with equal precedence are grouped within { } symbols.
79 Return the evaluation of expr1 if it is neither an empty string
80 nor zero; otherwise, returns the evaluation of expr2.
83 Return the evaluation of expr1 if neither expression evaluates to
84 an empty string or zero; otherwise, returns zero.
86 expr1 {=, >, >=, <, <=, !=} expr2
87 Return the results of integer comparison if both arguments are
88 integers; otherwise, returns the results of string comparison
89 using the locale-specific collation sequence. The result of each
90 comparison is 1 if the specified relation is true, or 0 if the
94 Return the results of addition or subtraction of integer-valued
98 Return the results of multiplication, integer division, or
99 remainder of integer-valued arguments.
102 The `:' operator matches expr1 against expr2, which must be a
103 regular expression. The regular expression is anchored to the
104 beginning of the string with an implicit `^'.
106 If the match succeeds and the pattern contains at least one regu-
107 lar expression subexpression `\(...\)', the string correspond-
108 ing to `\1' is returned; otherwise the matching operator
109 returns the number of characters matched. If the match fails and
110 the pattern contains a regular expression subexpression the null
111 string is returned; otherwise 0.
113 Parentheses are used for grouping in the usual manner.
115 The parser must be parsed with bison (bison is REQUIRED - yacc cannot
116 produce pure parsers, which are reentrant)
120 There is one conditional operator - the conditional goto :
122 ;exten => 1,2,gotoif,condition?label1:label2
124 If condition is true go to label1, else go to label2. Labels are interpreted
125 exactly as in the normal goto command.
127 "condition" is just a string. If the string is empty or "0", the condition
128 is considered to be false, if it's anything else, the condition is true.
129 This is designed to be used together with the expression syntax described
132 exten => 1,2,gotoif,$[${CALLERID} = 123456]?2|1:3|1
137 exten => s,2,SetVar,"vara=1"
138 exten => s,3,SetVar,"varb=$[${vara} + 2]"
139 exten => s,4,SetVar,"varc=$[${varb} * 2]"
140 exten => s,5,GotoIf,"$[${varc} = 6]?99|1:s|6";