Adding Define (Fixes #299)

Author: StartAutomating

docs/Define.md

@@ -0,0 +1,106 @@
+Define
+------
+### Synopsis
+defines a variable
+
+---
+### Description
+
+Defines a variable using a value provided during a build
+
+---
+### Examples
+#### EXAMPLE 1
+```PowerShell
+{
+    [Define(Value={Get-Random})]$RandomNumber
+}.Transpile()
+```
+
+#### EXAMPLE 2
+```PowerShell
+{
+    [Define(Value={$global:ThisValueExistsAtBuildTime})]$MyVariable
+}.Transpile()
+```
+
+---
+### Parameters
+#### **Value**
+
+The value to define.
+When this value is provided within an attribute as a ScriptBlock, the ScriptBlock will be run at build time.
+
+
+
+> **Type**: ```[PSObject]```
+
+> **Required**: true
+
+> **Position**: named
+
+> **PipelineInput**:false
+
+
+
+---
+#### **VariableAst**
+
+The variable the definition will be applied to.
+
+
+
+> **Type**: ```[VariableExpressionAst]```
+
+> **Required**: true
+
+> **Position**: named
+
+> **PipelineInput**:true (ByValue)
+
+
+
+---
+#### **ScriptBlock**
+
+A scriptblock the definition will be applied to
+
+
+
+> **Type**: ```[ScriptBlock]```
+
+> **Required**: true
+
+> **Position**: named
+
+> **PipelineInput**:true (ByValue)
+
+
+
+---
+#### **VariableName**
+
+The name of the variable.  If define is applied as an attribute of a variable, this does not need to be provided.
+
+
+
+> **Type**: ```[String]```
+
+> **Required**: false
+
+> **Position**: named
+
+> **PipelineInput**:false
+
+
+
+---
+### Syntax
+```PowerShell
+Define -Value <PSObject> -VariableAst <VariableExpressionAst> [-VariableName <String>] [<CommonParameters>]
+```
+```PowerShell
+Define -Value <PSObject> -ScriptBlock <ScriptBlock> [-VariableName <String>] [<CommonParameters>]
+```
+---
+