Merge pull request #1013 from WolframResearch/bugfix/455809

Add error message for invalid prompt generator

Author: rhennigan

Source/Chatbook/PromptGenerators/DefaultPromptGenerators.wl

@@ -11,6 +11,11 @@ HoldComplete[
     System`LLMPromptGenerator
 ];
 
+(* ::**************************************************************************************************************:: *)
+(* ::Section::Closed:: *)
+(*Messages*)
+Chatbook::InvalidPromptGenerator = "Expected a valid LLMPromptGenerator instead of `1`.";
+
 (* ::**************************************************************************************************************:: *)
 (* ::Section::Closed:: *)
 (*DefaultPromptGenerators*)
@@ -157,6 +162,7 @@ toPromptGenerator // beginDefinition;
 toPromptGenerator[ ___ ] /; $VersionNumber < 14.1 := Nothing;
 toPromptGenerator[ name_String ] := toPromptGenerator @ $defaultPromptGenerators @ name;
 toPromptGenerator[ generator: HoldPattern[ _LLMPromptGenerator ] ] := generator;
+toPromptGenerator[ other_ ] := throwFailure[ "InvalidPromptGenerator", other ];
 toPromptGenerator // endDefinition;
 
 (* ::**************************************************************************************************************:: *)