hover.schema.EXPRESSION_SL.md Maven / Gradle / Ivy

Go to download
## expression


Contained in [first-phase](https://docs.vespa.ai/en/reference/schema-reference.html#firstphase-rank) or
[second-phase](https://docs.vespa.ai/en/reference/schema-reference.html#secondphase-rank) or
[global-phase](https://docs.vespa.ai/en/reference/schema-reference.html#globalphase-rank).
Specify a [ranking expression](https://docs.vespa.ai/en/reference/ranking-expressions.html).
The expression can either be written directly or loaded from a file.
When writing it directly the syntax is:
```
expression: [ranking expression]
``` 

or
```
expression {
    [ranking expression]
    [ranking expression]
    [ranking expression]
}
``` 


The second format is primarily a convenience feature when using long expressions, enabling them
to be split over multiple lines.

Expressions can also be loaded from a separate file. This is useful when dealing with the long
expressions generated by e.g. MLR. The syntax is:
```
expression: file:[path-to-expressionfile]
``` 


The path is relative to the location of the schema definition file.
The file itself must end with `.expression`. This suffix is optional in the schema.
Therefore `expression: file:mlrranking.expression` and
`expression: file:mlrranking` are identical.
Both refer to a file called `mlrranking.expression` in the schemas directory.


> *NOTE:* Directories are not allowed in the path.





[Read more](https://docs.vespa.ai/en/reference/schema-reference.html#expression)