Pragmatic directives: Difference between revisions
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<lang sh>set -vx # Activate both script line output and command line arguments pragma
set +vx # Deactivate both pragmatic directives</lang>
=={{header|Wren}}==
The closest thing Wren has to a pragmatic directive is its '''import''' statement which loads a module, executes its source code and imports variable names from that module into the current scope.
Import statements can appear anywhere a variable declaration is allowed and in particular within conditional structures. This enables us to do things such as the following:
<lang ecmascript>/* windows.wren */
class Windows {
static message { "Using Windows." }
static lineSeparator { "\\r\\n" }
}</lang>
<lang ecmascript>/* linux.wren */
class Linux {
static message { "Using Linux." }
static lineSeparator { "\\n" }
}</lang>
<lang ecmascript>/*pragmatic_directives.wren*/
import "os" for Platform
var os
if (Platform.isWindows) {
import "/windows" for Windows
os = Windows
} else {
import "/linux" for Linux
os = Linux
}
System.print("%(os.message) which has a \"%(os.lineSeparator)\" line separator.")</lang>
{{out}}
From the last script, when run on a Linux system.
<pre>
$ wren_cli pragmatic_directives.wren
Using Linux which has a "\n" line separator.
</pre>
{{omit from|AWK}}
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