# Class ExpressionsCompiler

OptimaJet.Workflow.Core.CodeActions.ExpressionsCompiler

Prepares and compiles transition expression conditions and subprocess-name values into asynchronous delegates evaluated against [ProcessInstance](https://api.workflowengine.io/core/OptimaJet.Workflow.Core.Model/ProcessInstance/) objects.

Namespace: [OptimaJet.Workflow.Core.CodeActions](https://api.workflowengine.io/core/OptimaJet.Workflow.Core.CodeActions/)

```csharp
public static class ExpressionsCompiler
```

## Properties

`public static bool CompilationEnable { get; set; }` 

Gets or sets whether workflow expression compilation is enabled.

### Remarks

This static setting applies process-wide.

`public static ExpressionsCompilerOptions Options { get; set; }` 

Gets or sets the [ExpressionsCompilerOptions](https://api.workflowengine.io/core/OptimaJet.Workflow.Core.CodeActions/ExpressionsCompilerOptions/) used during expression compilation.

### Remarks

This static setting applies process-wide.

## Methods

`public static void RegisterAssembly(Assembly assembly)` 

Adds the namespaces used by types in an [Assembly](https://learn.microsoft.com/dotnet/api/system.reflection.assembly) to the imports available to subsequently compiled expressions.

### Parameters

| Name | Type | Description |
| --- | --- | --- |
| `assembly` | `Assembly` | The assembly whose distinct namespace names are added to the import set. |

### Exceptions

| Type | Description |
| --- | --- |
| `ReflectionTypeLoadException` | Thrown when one or more types from `assembly` cannot be loaded. |

### Remarks

Registration applies process-wide. This method adds namespace imports but does not add an assembly metadata reference to the compiler.

`public static ExpressionsInvoker CompileExpressions(ProcessDefinition processDefinition)` 

Compiles the [ConditionType.Expression](https://api.workflowengine.io/core/OptimaJet.Workflow.Core.Model/ConditionType/) conditions in a process scheme into one Boolean delegate per transition, keyed by the transition name.

### Parameters

| Name | Type | Description |
| --- | --- | --- |
| `processDefinition` | `ProcessDefinition` | The process scheme whose transition expressions are compiled. |

### Returns

| Type | Description |
| --- | --- |
| `ExpressionsInvoker` | An [ExpressionsInvoker](https://api.workflowengine.io/core/OptimaJet.Workflow.Core.CodeActions/ExpressionsInvoker/) containing the compiled transition delegates. The invoker is empty when expression compilation is disabled or the scheme contains no expression conditions. |

### Exceptions

| Type | Description |
| --- | --- |
| `Exception` | Thrown when an applicable transition expression cannot be compiled. |

### Remarks

Multiple expression conditions on the same transition are combined according to [TransitionDefinition.ConditionsConcatenationType](https://api.workflowengine.io/core/OptimaJet.Workflow.Core.Model/TransitionDefinition/). The compiler also applies [ConditionDefinition.ConditionInversion](https://api.workflowengine.io/core/OptimaJet.Workflow.Core.Model/ConditionDefinition/) and [ConditionDefinition.ResultOnPreExecution](https://api.workflowengine.io/core/OptimaJet.Workflow.Core.Model/ConditionDefinition/) before combining the conditions.

`public static SubprocessNameGetterInvoker CompileSubprocessNameGetters(ProcessDefinition processDefinition)` 

Compiles a subprocess-name delegate for each transition whose [TransitionDefinition.SubprocessName](https://api.workflowengine.io/core/OptimaJet.Workflow.Core.Model/TransitionDefinition/) is not blank.

### Parameters

| Name | Type | Description |
| --- | --- | --- |
| `processDefinition` | `ProcessDefinition` | The process scheme whose subprocess-name values are compiled. |

### Returns

| Type | Description |
| --- | --- |
| `SubprocessNameGetterInvoker` | A [SubprocessNameGetterInvoker](https://api.workflowengine.io/core/OptimaJet.Workflow.Core.CodeActions/SubprocessNameGetterInvoker/) containing delegates keyed by transition name. The invoker is empty when expression compilation is disabled or no transition has a nonblank subprocess name. |

### Remarks

Each configured value is first prepared and compiled as an expression that returns a subprocess name. If compilation fails, the prepared text is used as a literal name instead. Exceptions raised later while evaluating a successfully compiled expression are propagated.

## Remarks

Before compilation, recognized workflow operators and process-parameter references are converted to C# expression syntax.

[Previous ExpressionManager](https://api.workflowengine.io/core/OptimaJet.Workflow.Core.CodeActions/ExpressionManager/) [Next ExpressionsCompilerOptions](https://api.workflowengine.io/core/OptimaJet.Workflow.Core.CodeActions/ExpressionsCompilerOptions/)