# if

The `if` statement is used to conditionally execute one or more statements. In conjunction with an optional `else` statement it can cause one or other of two blocks of statements to be executed depending on whether an expression is true or false.

## Syntax

**`if`***`(expression)`***`{`**

```
`# Statements`
```

**`} [else {`**

```
`# Statements`
```

**`}]`**

## Details

If the condition evaluates to *true*, then the first block of statements is executed, and the second block (if present) is skipped over. If the condition evaluates to *false* then the first block of statements is skipped and the second block (if present) is executed.

The opening `{` character at the start of each block may be placed on a line of its own if preferred but the closing `}` must be on a line of its own.

Multiple conditions can be used in a single expression and combined with the boolean operators `&&` or `||` (for AND and OR respectively) so long as each condition is enclosed in braces. For example:

```
if (($JSON{example}.[status] == "OK") || (${override} == "enabled")) { 
    # Execute if the status is "OK" or if we have set ${override} to "enabled"
}
```

## Example

Given the source JSON in a file called `example.json`, the following USE script:

```
var JSON_dir = "examples\json"
buffer example = FILE "${JSON_dir}\doc.json"

var title = 

# For every element in the 'items' array ...
foreach $JSON{example}.[items] as this_item
{
    # Extract the item name and id
    var item_name = $JSON(this_item).[name]
    var sub_id = $JSON(this_item).[id]

    if (${sub_id} == 02) {
        # For every child of the 'subvalues' object ...
        foreach $JSON(this_item).[subvalues] as this_subvalue
        {
            # Get the subvalue name and value
            var sub_name = ${this_subvalue.NAME}
            var sub_value = ${this_subvalue.VALUE}

            # Render an output line
            print ${title} (id:${sub_id} -> Item: ${item_name} -> Subvalue:${sub_name} = ${sub_value} 
        }
    } else {
            print Skipping unwanted id: ${sub_id}
        }

}
discard {example}
terminate
```

will produce the following output:

```
    Skipping unwanted id: 01
    Example JSON data (id: 02) -> Item: Item number two -> Subvalue:0 = 10
    Example JSON data (id: 02) -> Item: Item number two -> Subvalue:10 = 442
    Example JSON data (id: 02) -> Item: Item number two -> Subvalue:100 = 783
    Example JSON data (id: 02) -> Item: Item number two -> Subvalue:1000 = 1009
```


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