add llama_chat_format_example

common/common.cpp

@@ -3020,6 +3020,17 @@ std::string llama_chat_format_single(const struct llama_model * model,
     return formatted;
 }
 
+std::string llama_chat_format_example(const struct llama_model * model,
+        const std::string & tmpl) {
+    std::vector<llama_chat_msg> msgs = {
+        {"system",    "You are a helpful assistant"},
+        {"user",      "Hello"},
+        {"assistant", "Hi there"},
+        {"user",      "How are you?"},
+    };
+    return llama_chat_apply_template(model, tmpl, msgs, true);
+}
+
 //
 // KV cache utils
 //

common/common.h

@@ -382,6 +382,10 @@ std::string llama_chat_format_single(const struct llama_model * model,
         const llama_chat_msg & new_msg,
         bool add_ass);
 
+// Returns an example of formatted chat
+std::string llama_chat_format_example(const struct llama_model * model,
+        const std::string & tmpl);
+
 //
 // KV cache utils
 //

examples/main/main.cpp

@@ -224,6 +224,8 @@ int main(int argc, char ** argv) {
                 __func__, n_ctx_train, n_ctx);
     }
 
+    LOG_TEE("%s: chat template example: %s\n", __func__, llama_chat_format_example(model, params.chat_template).c_str());
+
     // print system information
     {
         LOG_TEE("\n");

examples/server/server.cpp

@@ -2606,17 +2606,9 @@ int main(int argc, char ** argv) {
 
     // print sample chat example to make it clear which template is used
     {
-        json chat;
-        chat.push_back({{"role", "system"},    {"content", "You are a helpful assistant"}});
-        chat.push_back({{"role", "user"},      {"content", "Hello"}});
-        chat.push_back({{"role", "assistant"}, {"content", "Hi there"}});
-        chat.push_back({{"role", "user"},      {"content", "How are you?"}});
-
-        const std::string chat_example = format_chat(ctx_server.model, params.chat_template, chat);
-
         LOG_INFO("chat template", {
-            {"chat_example", chat_example},
-            {"built_in", params.chat_template.empty()},
+            {"chat_example", llama_chat_format_example(model)},
+            {"built_in",     params.chat_template.empty()},
         });
     }