crm-rush/api/soft/smarty/5.4.1/docs/designers/language-basic-syntax/language-syntax-operators.md

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2024-09-27 15:28:55 +05:00
# Operators
## Basic
Various basic operators can be applied directly to variable values.
## Examples
```smarty
{$foo + 1}
{$foo * $bar}
{$foo->bar - $bar[1] * $baz->foo->bar() -3 * 7}
{if ($foo + $bar.test % $baz * 134232 + 10 + $b + 10)}
...
{/if}
{$foo = $foo + $bar}
```
> **Note**
>
> Although Smarty can handle some very complex expressions and syntax,
> it is a good rule of thumb to keep the template syntax minimal and
> focused on presentation. If you find your template syntax getting too
> complex, it may be a good idea to move the bits that do not deal
> explicitly with presentation to PHP by way of plugins or modifiers.
## List
The following is a list of recognized operators, which must be
separated from surrounding elements by spaces. Note that items listed in
\[brackets\] are optional. PHP equivalents are shown where applicable.
| Operator | Alternates | Syntax Example | Meaning | PHP Equivalent |
|--------------------|------------|----------------------|--------------------------------|--------------------|
| == | eq | $a eq $b | equals | == |
| != | ne, neq | $a neq $b | not equals | != |
| > | gt | $a gt $b | greater than | > |
| < | lt | $a lt $b | less than | < |
| >= | gte, ge | $a ge $b | greater than or equal | >= |
| <= | lte, le | $a le $b | less than or equal | <= |
| === | | $a === 0 | check for identity | === |
| ! | not | not $a | negation (unary) | ! |
| % | mod | $a mod $b | modulo | % |
| is \[not\] div by | | $a is not div by 4 | divisible by | $a % $b == 0 |
| is \[not\] even | | $a is not even | \[not\] an even number (unary) | $a % 2 == 0 |
| is \[not\] even by | | $a is not even by $b | grouping level \[not\] even | ($a / $b) % 2 == 0 |
| is \[not\] odd | | $a is not odd | \[not\] an odd number (unary) | $a % 2 != 0 |
| is \[not\] odd by | | $a is not odd by $b | \[not\] an odd grouping | ($a / $b) % 2 != 0 |
| is in | | $a is in $b | exists in array | in_array($a, $b) |
| is \[not\] in | | $a is not in $b | does not exist in array | !in_array($a, $b) |
## Ternary
You can use the `?:` (or ternary) operator to test one expression and present the value
of the second or third expression, based on the result of the test.
In other words:
```smarty
{$test ? "OK" : "FAIL"}
```
will result in OK if `$test` is set to true, and in FAIL otherwise.
There is also a shorthand `?:` operator:
```smarty
{$myVar ?: "empty"}
```
will result in 'empty' if `$myVar` is not set or set to something that evaluates to false, such as an empty string.
If `$myVar` is set to something that evaluates to true, the value of `$myVar` is returned. So, the following will
return 'hello':
```smarty
{$myVar="hello"}
{$myVar ?: "empty"}
```
## Testing for null
If "something that evaluates to false" is to broad a test for you, you can use the `??` (or null coalescing) operator
to trigger only if the tested value is undefined or set to null.
```smarty
{$myVar ?? "empty"}
```
will result in 'empty' if `$myVar` is not set or set to null.
If `$myVar` is set to something that evaluates to anything else, the value of `$myVar` is returned. So, the following will
return an empty string (''):
```smarty
{$myVar=""}
{$myVar ?: "this is not shown"}
```