What are they?

Expressions are a mechanism for the auto-completion of values which may not be known until build execution time (for example the current build number).  They can also be used to autocomplete variables.

Where can I use them?

Expressions can be utilised in several dialog fields throughout Continua (they are especially useful within stage actions, and build event handlers).  

The expansion icon (below) denotes fields that have expression capabilities. Note is some areas, such as configuration variables, you can click on this icon to disable expressions

Expression Expansion

To initiate an expansion, simply type the dollar symbol '$' and the expression auto complete will present (note: not all objects are available in all fields).

Available Expression Objects

Different expression objects are available for each expandable field depending on which stage in the build process the expression will be evaluated at, and whether it will be evaluated on the server or an agent.

Agent-side expression objects

Stage Actions, Workspace Rules, and Expression Variables

Expandable fields on Action dialogs, and the Workspace Rules tab of the Stage Options dialog in the Stages step of the configuration wizard, and the Edit Variable dialog in various areas, support the following root expression objects.

• Agent
• Build
• Configuration
• Project
• Server
• Source
• Stage
• Utils
• Workspace

Server-side expression objects

Triggers and Repositories

Most expandable fields on the Edit Repository dialog and the Edit Trigger dialog, except for the Variables and Artifacts tabs for Build Completed triggers, support the following root expression objects.

• Server
• Utils

Variables and Artifacts for Build Completed Triggers

Expandable fields on the Variables and Artifacts tabs for Build Completed triggers, support the following root expression objects.

• Build
• Configuration
• Project
• Server
• Source
• Utils

Version Format

The Version Format field on the Stages step of the configuration wizard, supports the following root expression objects. 

• Build
• Server
• Source
• Utils

Variables  

Expandable fields on the Edit Variable dialog (for variable types other than Expression) , support the following root expression objects.

• Configuration
• Project
• Server
• Utils

Configuration Conditions, Build Event Handlers and Agent Conditions

Expandable fields when editing Configuration Conditions in the Conditions step of the configuration wizard, in the Edit Build Event Handlers dialog, and in Agent Conditions on the Agent page under Administration, support the following root expression objects.

• Build
• Configuration
• Project
• Server
• Source
• Utils
• Workspace

Agent Requirements

Expandable fields on the Agent Requirements tab of the Stage Options dialog in the Stages step of the configuration wizard, support the following root expression objects.

• Agent
• Build
• Server
• Source
• Utils
• Workspace

Stage Gate, Promote Conditions and Skip Conditions

Expandable fields on the Edit Stage Gate dialog, Promote Conditions and Skip Conditions tabs of the Stage Options dialog in the Stages step of the configuration wizard, support the following root expression objects.

• Build
• Server
• Stage
• Utils

Reports

Expandable fields on the Edit Report dialog, support the following root expression objects.

• Build
• Configuration
• Project
• Server
• Source
• Workspace

TO MOVE....

Repository (used by $Source )

Changeset (used by $Source)

Stage (used by $Build)

Metrics (used by $Build)

UnitTests (used by $Build.Metrics)

Version (used by $Build.Version)

Default (used by $Build.Version.Default)

DotNet (used by $Build.Version.DotNet)