Change function result type from string to any

Updated the return type of functions and related code from `string` to `any` to improve flexibility and support more diverse outputs. Adjusted function implementations, signatures, and handling of results accordingly.

function.go

@@ -4,11 +4,13 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
-	"gitea.stevedudenhoeffer.com/steve/go-llm/schema"
-	"github.com/sashabaranov/go-openai"
-	"github.com/sashabaranov/go-openai/jsonschema"
 	"reflect"
 	"time"
+
+	"github.com/sashabaranov/go-openai"
+	"github.com/sashabaranov/go-openai/jsonschema"
+
+	"gitea.stevedudenhoeffer.com/steve/go-llm/schema"
 )
 
 type Function struct {
@@ -31,7 +33,7 @@ type Function struct {
 	definition *jsonschema.Definition
 }
 
-func (f *Function) Execute(ctx *Context, input string) (string, error) {
+func (f *Function) Execute(ctx *Context, input string) (any, error) {
 	if !f.fn.IsValid() {
 		return "", fmt.Errorf("function %s is not implemented", f.Name)
 	}
@@ -46,7 +48,7 @@ func (f *Function) Execute(ctx *Context, input string) (string, error) {
 	}
 
 	// now we can call the function
-	exec := func(ctx *Context) (string, error) {
+	exec := func(ctx *Context) (any, error) {
 		out := f.fn.Call([]reflect.Value{reflect.ValueOf(ctx), p.Elem()})
 
 		if len(out) != 2 {
@@ -54,7 +56,7 @@ func (f *Function) Execute(ctx *Context, input string) (string, error) {
 		}
 
 		if out[1].IsNil() {
-			return out[0].String(), nil
+			return out[0].Interface(), nil
 		}
 
 		return "", out[1].Interface().(error)