Add new functions for credential handling, node lookup, and context-aware parameter overrides; update module version to 1.2.0

Readme.md

@@ -424,6 +424,102 @@ ConfigDbName    : SharePoint_corp_TST_Farm_Config
 
 `reference(path)` resolves another value from the configuration data by path. `reference(path, property)` resolves the value and then returns a property from it, such as `UserName` from a `PSCredential`.
 
+### Credentials
+
+`credentialWithDomain(credential, domain)` returns a new `PSCredential` with the same password and a domain-qualified user name. If the user name already contains `DOMAIN\User` or `user@domain`, the original credential is returned.
+
+This is useful when a secret backend such as KeePass stores the user name without a domain, but the DSC resource expects a domain-qualified credential:
+
+```powershell
+Parameters = @{
+    DomainNetBIOS = @{
+        Type = 'string'
+        Value = 'CONTOSO'
+    }
+
+    FarmCredential = @{
+        Type = 'credential'
+        Value = @{
+            Provider = 'SecretManagement'
+            Vault = 'KeePass'
+            Name = 'SharePoint/FarmAccount'
+            Domain = "[parameters('DomainNetBIOS')]"
+        }
+    }
+}
+```
+
+The same transformation can also be used explicitly in expressions:
+
+```powershell
+FarmCredentialQualified = @{
+    Type = 'credential'
+    DefaultValue = "[credentialWithDomain(parameters('FarmCredential'), parameters('DomainNetBIOS'))]"
+}
+```
+
+### Node Lookup
+
+`firstNodeNameWhere(propertyName)` returns the first `NodeName` from `AllNodes` where the named property is `$true`.
+`firstNodeNameWhere(propertyName, expectedValue)` compares the property with the provided value.
+
+```powershell
+AllNodes = @(
+    @{
+        NodeName = 'SP01'
+        RunCentralAdmin = $true
+    }
+    @{
+        NodeName = 'SP02'
+        RunCentralAdmin = $false
+    }
+)
+```
+
+```powershell
+CentralAdministrationHostName = @{
+    Type = 'string'
+    DefaultValue = "[firstNodeNameWhere('RunCentralAdmin')]"
+}
+
+CentralAdministrationUrl = @{
+    Type = 'string'
+    DefaultValue = "[format('https://{0}:{1}', parameters('CentralAdministrationHostName'), parameters('CentralAdministrationPort'))]"
+}
+```
+
+If a fixed URL is required, set an explicit parameter value and the default expression is not used.
+
+### Parent Map Key
+
+`parentKey()` returns the key of the map that contains the current expression property. It can be used to derive resource-specific parameter names while retaining a shared default:
+
+```powershell
+Parameters = @{
+    DefaultWebApplicationAuthenticationMethod = @{
+        Type = 'string'
+        DefaultValue = 'NTLM'
+    }
+    HNSCWebApplicationAuthenticationMethod = @{
+        Type = 'string'
+        Value = 'Kerberos'
+    }
+}
+
+Resources = @{
+    WebApplications = @{
+        HNSC = @{
+            AuthenticationMethod = "[coalesce(parameters(concat(parentKey(), 'WebApplicationAuthenticationMethod')), parameters('DefaultWebApplicationAuthenticationMethod'))]"
+        }
+        MySite = @{
+            AuthenticationMethod = "[coalesce(parameters(concat(parentKey(), 'WebApplicationAuthenticationMethod')), parameters('DefaultWebApplicationAuthenticationMethod'))]"
+        }
+    }
+}
+```
+
+The `HNSC` resource resolves the optional `HNSCWebApplicationAuthenticationMethod` override. `MySite` falls back to `DefaultWebApplicationAuthenticationMethod` when no corresponding override parameter exists.
+
 ### String Composition
 
 ```powershell
@@ -628,6 +724,10 @@ ConfigDbName    : SharePoint_corp_TST_Farm_Config
 - `variables(name)`
 - `reference(path)`
 - `reference(path, property)`
+- `credentialWithDomain(credential, domain)`
+- `firstNodeNameWhere(propertyName)`
+- `firstNodeNameWhere(propertyName, expectedValue)`
+- `parentKey()`
 - `concat(value1, value2, ...)`
 - `format(formatString, value1, value2, ...)`
 - `coalesce(value1, value2, ...)`