patch 9.0.1031: Vim9 class is not implemented yetv9.0.1031

Problem:    Vim9 class is not implemented yet.
Solution:   Add very basic class support.

29 files changed, 1066 insertions, 74 deletions

diff --git a/runtime/doc/vim9class.txt b/runtime/doc/vim9class.txt
index cb86b4d136..b018a105c3 100644
--- a/runtime/doc/vim9class.txt
+++ b/runtime/doc/vim9class.txt
@@ -336,6 +336,9 @@ Defining a class ~
 A class is defined between `:class` and `:endclass`.  The whole class is
 defined in one script file.  It is not possible to add to a class later.
 
+A class can only be defined in a |Vim9| script file.  *E1315*
+A class cannot be defined inside a function.
+
 It is possible to define more than one class in a script file.  Although it
 usually is better to export only one main class.  It can be useful to define
 types, enums and helper classes though.
@@ -369,9 +372,9 @@ A class can extend one other class.
 							*implements*
 A class can implement one or more interfaces.
 							*specifies*
-A class can declare it's interface, the object members and methods, with a
+A class can declare its interface, the object members and methods, with a
 named interface.  This avoids the need for separately specifying the
-interface, which is often done an many languages, especially Java.
+interface, which is often done in many languages, especially Java.
 
 
 Defining an interface ~
@@ -634,7 +637,7 @@ directly writing you get an error, which makes you wonder if you actually want
 to allow that.  This helps writing code with fewer mistakes.
 
 
-Making object membes private with an underscore ~
+Making object members private with an underscore ~
 
 When an object member is private, it can only be read and changed inside the
 class (and in sub-classes), then it cannot be used outside of the class.
diff --git a/src/errors.h b/src/errors.h
index 8d1feb39b6..6230527a70 100644
--- a/src/errors.h
+++ b/src/errors.h
@@ -3346,4 +3346,28 @@ EXTERN char e_not_allowed_to_add_or_remove_entries_str[]
 #ifdef FEAT_EVAL
 EXTERN char e_class_name_must_start_with_uppercase_letter_str[]
 	INIT(= N_("E1314: Class name must start with an uppercase letter: %s"));
+EXTERN char e_white_space_required_after_class_name_str[]
+	INIT(= N_("E1315: White space required after class name: %s"));
+EXTERN char e_class_can_only_be_defined_in_vim9_script[]
+	INIT(= N_("E1316: Class can only be defined in Vim9 script"));
+EXTERN char e_invalid_object_member_declaration_str[]
+	INIT(= N_("E1317: Invalid object member declaration: %s"));
+EXTERN char e_not_valid_command_in_class_str[]
+	INIT(= N_("E1318: Not a valid command in a class: %s"));
+EXTERN char e_using_class_as_number[]
+	INIT(= N_("E1319: Using a class as a Number"));
+EXTERN char e_using_object_as_number[]
+	INIT(= N_("E1320: Using an object as a Number"));
+EXTERN char e_using_class_as_float[]
+	INIT(= N_("E1321: Using a class as a Float"));
+EXTERN char e_using_object_as_float[]
+	INIT(= N_("E1322: Using an object as a Float"));
+EXTERN char e_using_class_as_string[]
+	INIT(= N_("E1323: Using a class as a String"));
+EXTERN char e_using_object_as_string[]
+	INIT(= N_("E1324: Using an object as a String"));
+EXTERN char e_method_not_found_on_class_str_str[]
+	INIT(= N_("E1325: Method not found on class \"%s\": %s"));
+EXTERN char e_member_not_found_on_object_str_str[]
+	INIT(= N_("E1326: Member not found on object \"%s\": %s"));
 #endif
diff --git a/src/eval.c b/src/eval.c
index 20883d4309..917e0a852c 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -1548,7 +1548,7 @@ set_var_lval(
     {
 	cc = *endp;
 	*endp = NUL;
-	if (in_vim9script() && check_reserved_name(lp->ll_name) == FAIL)
+	if (in_vim9script() && check_reserved_name(lp->ll_name, NULL) == FAIL)
 	    return;
 
 	if (lp->ll_blob != NULL)
@@ -1724,6 +1724,8 @@ tv_op(typval_T *tv1, typval_T *tv2, char_u *op)
 	    case VAR_JOB:
 	    case VAR_CHANNEL:
 	    case VAR_INSTR:
+	    case VAR_CLASS:
+	    case VAR_OBJECT:
 		break;
 
 	    case VAR_BLOB:
@@ -3850,12 +3852,25 @@ handle_predefined(char_u *s, int len, typval_T *rettv)
 		    return OK;
 		}
 		break;
+	case 10: if (STRNCMP(s, "null_class", 10) == 0)
+		{
+		    rettv->v_type = VAR_CLASS;
+		    rettv->vval.v_class = NULL;
+		    return OK;
+		}
+		 break;
 	case 11: if (STRNCMP(s, "null_string", 11) == 0)
 		{
 		    rettv->v_type = VAR_STRING;
 		    rettv->vval.v_string = NULL;
 		    return OK;
 		}
+		if (STRNCMP(s, "null_object", 11) == 0)
+		{
+		    rettv->v_type = VAR_OBJECT;
+		    rettv->vval.v_object = NULL;
+		    return OK;
+		}
 		break;
 	case 12:
 		if (STRNCMP(s, "null_channel", 12) == 0)
@@ -4685,6 +4700,8 @@ check_can_index(typval_T *rettv, int evaluate, int verbose)
 	case VAR_JOB:
 	case VAR_CHANNEL:
 	case VAR_INSTR:
+	case VAR_CLASS:
+	case VAR_OBJECT:
 	    if (verbose)
 		emsg(_(e_cannot_index_special_variable));
 	    return FAIL;
@@ -4788,6 +4805,8 @@ eval_index_inner(
 	case VAR_JOB:
 	case VAR_CHANNEL:
 	case VAR_INSTR:
+	case VAR_CLASS:
+	case VAR_OBJECT:
 	    break; // not evaluating, skipping over subscript
 
 	case VAR_NUMBER:
@@ -5781,6 +5800,16 @@ echo_string_core(
 	    r = (char_u *)"instructions";
 	    break;
 
+	case VAR_CLASS:
+	    *tofree = NULL;
+	    r = (char_u *)"class";
+	    break;
+
+	case VAR_OBJECT:
+	    *tofree = NULL;
+	    r = (char_u *)"object";
+	    break;
+
 	case VAR_FLOAT:
 	    *tofree = NULL;
 	    vim_snprintf((char *)numbuf, NUMBUFLEN, "%g", tv->vval.v_float);
@@ -6588,6 +6617,20 @@ handle_subscript(
 		ret = FAIL;
 	    }
 	}
+	else if (**arg == '.' && (rettv->v_type == VAR_CLASS
+					       || rettv->v_type == VAR_OBJECT))
+	{
+	    // class member: SomeClass.varname
+	    // class method: SomeClass.SomeMethod()
+	    // class constructor: SomeClass.new()
+	    // object member: someObject.varname
+	    // object method: someObject.SomeMethod()
+	    if (class_object_index(arg, rettv, evalarg, verbose) == FAIL)
+	    {
+		clear_tv(rettv);
+		ret = FAIL;
+	    }
+	}
 	else
 	    break;
     }
@@ -6644,6 +6687,8 @@ item_copy(
 	case VAR_JOB:
 	case VAR_CHANNEL:
 	case VAR_INSTR:
+	case VAR_CLASS:
+	case VAR_OBJECT:
 	    copy_tv(from, to);
 	    break;
 	case VAR_LIST:
diff --git a/src/evalfunc.c b/src/evalfunc.c
index 84df6a62aa..3db4bb7b24 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -3770,6 +3770,12 @@ f_empty(typval_T *argvars, typval_T *rettv)
 	case VAR_SPECIAL:
 	    n = argvars[0].vval.v_number != VVAL_TRUE;
 	    break;
+	case VAR_CLASS:
+	    n = argvars[0].vval.v_class != NULL;
+	    break;
+	case VAR_OBJECT:
+	    n = argvars[0].vval.v_object != NULL;
+	    break;
 
 	case VAR_BLOB:
 	    n = argvars[0].vval.v_blob == NULL
@@ -7267,6 +7273,8 @@ f_len(typval_T *argvars, typval_T *rettv)
 	case VAR_JOB:
 	case VAR_CHANNEL:
 	case VAR_INSTR:
+	case VAR_CLASS:
+	case VAR_OBJECT:
 	    emsg(_(e_invalid_type_for_len));
 	    break;
     }
@@ -10183,7 +10191,9 @@ f_substitute(typval_T *argvars, typval_T *rettv)
 
     if (argvars[2].v_type == VAR_FUNC
 	    || argvars[2].v_type == VAR_PARTIAL
-	    || argvars[2].v_type == VAR_INSTR)
+	    || argvars[2].v_type == VAR_INSTR
+	    || argvars[2].v_type == VAR_CLASS
+	    || argvars[2].v_type == VAR_OBJECT)
 	expr = &argvars[2];
     else
 	sub = tv_get_string_buf_chk(&argvars[2], subbuf);
@@ -10617,6 +10627,8 @@ f_type(typval_T *argvars, typval_T *rettv)
 	case VAR_CHANNEL: n = VAR_TYPE_CHANNEL; break;
 	case VAR_BLOB:    n = VAR_TYPE_BLOB; break;
 	case VAR_INSTR:   n = VAR_TYPE_INSTR; break;
+	case VAR_CLASS:   n = VAR_TYPE_CLASS; break;
+	case VAR_OBJECT:  n = VAR_TYPE_OBJECT; break;
 	case VAR_UNKNOWN:
 	case VAR_ANY:
 	case VAR_VOID:
diff --git a/src/evalvars.c b/src/evalvars.c
index 31cc760bf0..d9466691f4 100644
--- a/src/evalvars.c
+++ b/src/evalvars.c
@@ -2264,6 +2264,8 @@ item_lock(typval_T *tv, int deep, int lock, int check_refcount)
 	case VAR_JOB:
 	case VAR_CHANNEL:
 	case VAR_INSTR:
+	case VAR_CLASS:
+	case VAR_OBJECT:
 	    break;
 
 	case VAR_BLOB:
diff --git a/src/if_py_both.h b/src/if_py_both.h
index 5589af678e..8dd7f09b55 100644
--- a/src/if_py_both.h
+++ b/src/if_py_both.h
@@ -6422,6 +6422,8 @@ ConvertToPyObject(typval_T *tv)
 	case VAR_CHANNEL:
 	case VAR_JOB:
 	case VAR_INSTR:
+	case VAR_CLASS:
+	case VAR_OBJECT:
 	    Py_INCREF(Py_None);
 	    return Py_None;
 	case VAR_BOOL:
diff --git a/src/json.c b/src/json.c
index 80120acb30..9c084b4605 100644
--- a/src/json.c
+++ b/src/json.c
@@ -308,6 +308,8 @@ json_encode_item(garray_T *gap, typval_T *val, int copyID, int options)
 	case VAR_JOB:
 	case VAR_CHANNEL:
 	case VAR_INSTR:
+	case VAR_CLASS:
+	case VAR_OBJECT:
 	    semsg(_(e_cannot_json_encode_str), vartype_name(val->v_type));
 	    return FAIL;
 
diff --git a/src/proto/userfunc.pro b/src/proto/userfunc.pro
index ee17049ce6..5c865ce8de 100644
--- a/src/proto/userfunc.pro
+++ b/src/proto/userfunc.pro
@@ -7,6 +7,7 @@ char_u *register_cfunc(cfunc_T cb, cfunc_free_T cb_free, void *state);
 int get_lambda_tv(char_u **arg, typval_T *rettv, int types_optional, evalarg_T *evalarg);
 char_u *deref_func_name(char_u *name, int *lenp, partial_T **partialp, type_T **type, int no_autoload, int new_function, int *found_var);
 void emsg_funcname(char *ermsg, char_u *name);
+int get_func_arguments(char_u **arg, evalarg_T *evalarg, int partial_argc, typval_T *argvars, int *argcount);
 int get_func_tv(char_u *name, int len, typval_T *rettv, char_u **arg, evalarg_T *evalarg, funcexe_T *funcexe);
 char_u *fname_trans_sid(char_u *name, char_u *fname_buf, char_u **tofree, int *error);
 void func_name_with_sid(char_u *name, int sid, char_u *buffer);
@@ -45,7 +46,7 @@ char_u *get_scriptlocal_funcname(char_u *funcname);
 char_u *alloc_printable_func_name(char_u *fname);
 char_u *save_function_name(char_u **name, int *is_global, int skip, int flags, funcdict_T *fudi);
 void list_functions(regmatch_T *regmatch);
-ufunc_T *define_function(exarg_T *eap, char_u *name_arg, garray_T *lines_to_free);
+ufunc_T *define_function(exarg_T *eap, char_u *name_arg, garray_T *lines_to_free, class_T *class_arg);
 void ex_function(exarg_T *eap);
 ufunc_T *find_func_by_name(char_u *name, compiletype_T *compile_type);
 void ex_defcompile(exarg_T *eap);
diff --git a/src/proto/vim9class.pro b/src/proto/vim9class.pro
index 4e55178bda..4c6e12dab7 100644
--- a/src/proto/vim9class.pro
+++ b/src/proto/vim9class.pro
@@ -1,6 +1,12 @@
 /* vim9class.c */
 void ex_class(exarg_T *eap);
+type_T *class_member_type(class_T *cl, char_u *name, char_u *name_end, int *member_idx);
 void ex_interface(exarg_T *eap);
 void ex_enum(exarg_T *eap);
 void ex_type(exarg_T *eap);
+int class_object_index(char_u **arg, typval_T *rettv, evalarg_T *evalarg, int verbose);
+void copy_object(typval_T *from, typval_T *to);
+void object_unref(object_T *obj);
+void copy_class(typval_T *from, typval_T *to);
+void class_unref(typval_T *tv);
 /* vim: set ft=c : */
diff --git a/src/proto/vim9instr.pro b/src/proto/vim9instr.pro
index 87914f36d2..04d76822fe 100644
--- a/src/proto/vim9instr.pro
+++ b/src/proto/vim9instr.pro
@@ -3,6 +3,7 @@ isn_T *generate_instr(cctx_T *cctx, isntype_T isn_type);
 isn_T *generate_instr_drop(cctx_T *cctx, isntype_T isn_type, int drop);
 isn_T *generate_instr_type(cctx_T *cctx, isntype_T isn_type, type_T *type);
 isn_T *generate_instr_debug(cctx_T *cctx);
+int generate_CONSTRUCT(cctx_T *cctx, class_T *cl);
 int may_generate_2STRING(int offset, int tolerant, cctx_T *cctx);
 int generate_add_instr(cctx_T *cctx, vartype_T vartype, type_T *type1, type_T *type2, exprtype_T expr_type);
 vartype_T operator_type(type_T *type1, type_T *type2);
diff --git a/src/proto/vim9script.pro b/src/proto/vim9script.pro
index 0e98039e8b..9a0bcdf37c 100644
--- a/src/proto/vim9script.pro
+++ b/src/proto/vim9script.pro
@@ -19,5 +19,5 @@ void update_vim9_script_var(int create, dictitem_T *di, char_u *name, int flags,
 void hide_script_var(scriptitem_T *si, int idx, int func_defined);
 svar_T *find_typval_in_script(typval_T *dest, scid_T sid, int must_find);
 int check_script_var_type(svar_T *sv, typval_T *value, char_u *name, where_T where);
-int check_reserved_name(char_u *name);
+int check_reserved_name(char_u *name, cctx_T *cctx);
 /* vim: set ft=c : */
diff --git a/src/proto/vim9type.pro b/src/proto/vim9type.pro
index 3c860928b1..98c6091e98 100644
--- a/src/proto/vim9type.pro
+++ b/src/proto/vim9type.pro
@@ -1,4 +1,5 @@
 /* vim9type.c */
+type_T *get_type_ptr(garray_T *type_gap);
 type_T *copy_type(type_T *type, garray_T *type_gap);
 void clear_type_list(garray_T *gap);
 type_T *alloc_type(type_T *type);
diff --git a/src/structs.h b/src/structs.h
index 497a35306e..f7ae16b758 100644
--- a/src/structs.h
+++ b/src/structs.h
@@ -1406,6 +1406,9 @@ typedef struct {
 typedef struct isn_S isn_T;	    // instruction
 typedef struct dfunc_S dfunc_T;	    // :def function
 
+typedef struct type_S type_T;
+typedef struct ufunc_S ufunc_T;
+
 typedef struct jobvar_S job_T;
 typedef struct readq_S readq_T;
 typedef struct writeq_S writeq_T;
@@ -1415,6 +1418,8 @@ typedef struct channel_S channel_T;
 typedef struct cctx_S cctx_T;
 typedef struct ectx_S ectx_T;
 typedef struct instr_S instr_T;
+typedef struct class_S class_T;
+typedef struct object_S object_T;
 
 typedef enum
 {
@@ -1434,16 +1439,18 @@ typedef enum
     VAR_JOB,		// "v_job" is used
     VAR_CHANNEL,	// "v_channel" is used
     VAR_INSTR,		// "v_instr" is used
+    VAR_CLASS,		// "v_class" is used
+    VAR_OBJECT,		// "v_object" is used
 } vartype_T;
 
 // A type specification.
-typedef struct type_S type_T;
 struct type_S {
     vartype_T	    tt_type;
     int8_T	    tt_argcount;    // for func, incl. vararg, -1 for unknown
     int8_T	    tt_min_argcount; // number of non-optional arguments
     char_u	    tt_flags;	    // TTFLAG_ values
     type_T	    *tt_member;	    // for list, dict, func return type
+				    // for class: class_T
     type_T	    **tt_args;	    // func argument types, allocated
 };
 
@@ -1452,6 +1459,38 @@ typedef struct {
     type_T	*type_decl;	    // declared type or equal to type_current
 } type2_T;
 
+/*
+ * Entry for an object member variable.
+ */
+typedef struct {
+    char_u	*om_name;  // allocated
+    type_T	*om_type;
+} objmember_T;
+
+// "class_T": used for v_class of typval of VAR_CLASS
+struct class_S
+{
+    char_u	*class_name;		// allocated
+    int		class_refcount;
+
+    int		class_obj_member_count;
+    objmember_T	*class_obj_members;	// allocated
+
+    int		class_obj_method_count;
+    ufunc_T	**class_obj_methods;	// allocated
+    ufunc_T	*class_new_func;	// new() function that was created
+
+    garray_T	class_type_list;	// used for type pointers
+    type_T	class_type;
+};
+
+// Used for v_object of typval of VAR_OBJECT.
+// The member variables follow in an array of typval_T.
+struct object_S {
+    class_T	*obj_class;  // class this object is created for
+    int		obj_refcount;
+};
+
 #define TTFLAG_VARARGS	0x01	    // func args ends with "..."
 #define TTFLAG_BOOL_OK	0x02	    // can be converted to bool
 #define TTFLAG_STATIC	0x04	    // one of the static types, e.g. t_any
@@ -1467,17 +1506,19 @@ typedef struct
     union
     {
 	varnumber_T	v_number;	// number value
-	float_T		v_float;	// floating number value
-	char_u		*v_string;	// string value (can be NULL!)
-	list_T		*v_list;	// list value (can be NULL!)
-	dict_T		*v_dict;	// dict value (can be NULL!)
+	float_T		v_float;	// floating point number value
+	char_u		*v_string;	// string value (can be NULL)
+	list_T		*v_list;	// list value (can be NULL)
+	dict_T		*v_dict;	// dict value (can be NULL)
 	partial_T	*v_partial;	// closure: function with args
 #ifdef FEAT_JOB_CHANNEL
-	job_T		*v_job;		// job value (can be NULL!)
-	channel_T	*v_channel;	// channel value (can be NULL!)
+	job_T		*v_job;		// job value (can be NULL)
+	channel_T	*v_channel;	// channel value (can be NULL)
 #endif
-	blob_T		*v_blob;	// blob value (can be NULL!)
+	blob_T		*v_blob;	// blob value (can be NULL)
 	instr_T		*v_instr;	// instructions to execute
+	class_T		*v_class;	// class value (can be NULL)
+	object_T	*v_object;	// object value (can be NULL)
     }		vval;
 } typval_T;
 
@@ -1663,7 +1704,7 @@ typedef enum {
  * Structure to hold info for a user function.
  * When adding a field check copy_lambda_to_global_func().
  */
-typedef struct
+struct ufunc_S
 {
     int		uf_varargs;	// variable nr of arguments (old style)
     int		uf_flags;	// FC_ flags
@@ -1671,6 +1712,9 @@ typedef struct
     int		uf_cleared;	// func_clear() was already called
     def_status_T uf_def_status; // UF_NOT_COMPILED, UF_TO_BE_COMPILED, etc.
     int		uf_dfunc_idx;	// only valid if uf_def_status is UF_COMPILED
+
+    class_T	*uf_class;	// for object method and constructor
+
     garray_T	uf_args;	// arguments, including optional arguments
     garray_T	uf_def_args;	// default argument expressions
     int		uf_args_visible; // normally uf_args.ga_len, less when
@@ -1731,7 +1775,7 @@ typedef struct
     char_u	uf_name[4];	// name of function (actual size equals name);
 				// can start with <SNR>123_ (<SNR> is K_SPECIAL
 				// KS_EXTRA KE_SNR)
-} ufunc_T;
+};
 
 // flags used in uf_flags
 #define FC_ABORT    0x01	// abort function on error
@@ -1750,6 +1794,9 @@ typedef struct
 				// copy_lambda_to_global_func()
 #define FC_LAMBDA   0x2000	// one line "return {expr}"
 
+#define FC_OBJECT   010000	// object method
+#define FC_NEW	    030000	// constructor (also an object method)
+
 #define MAX_FUNC_ARGS	20	// maximum number of function arguments
 #define VAR_SHORT_LEN	20	// short variable name length
 #define FIXVAR_CNT	12	// number of fixed variables
diff --git a/src/testdir/Make_all.mak b/src/testdir/Make_all.mak
index 1ac29b1b6a..886bb08ad8 100644
--- a/src/testdir/Make_all.mak
+++ b/src/testdir/Make_all.mak
@@ -37,6 +37,7 @@ SCRIPTS_TINY_OUT = \
 TEST_VIM9 = \
 	test_vim9_assign \
 	test_vim9_builtin \
+	test_vim9_class \
 	test_vim9_cmd \
 	test_vim9_disassemble \
 	test_vim9_expr \
@@ -48,6 +49,7 @@ TEST_VIM9 = \
 TEST_VIM9_RES = \
 	test_vim9_assign.res \
 	test_vim9_builtin.res \
+	test_vim9_class.res \
 	test_vim9_cmd.res \
 	test_vim9_disassemble.res \
 	test_vim9_expr.res \
diff --git a/src/testdir/test_vim9_class.vim b/src/testdir/test_vim9_class.vim
new file mode 100644
index 0000000000..6742ea757c
--- /dev/null
+++ b/src/testdir/test_vim9_class.vim
@@ -0,0 +1,145 @@
+" Test Vim9 classes
+
+source check.vim
+import './vim9.vim' as v9
+
+def Test_class_basic()
+  var lines =<< trim END
+      class NotWorking
+      endclass
+  END
+  v9.CheckScriptFailure(lines, 'E1316:')
+
+  lines =<< trim END
+      vim9script
+      class notWorking
+      endclass
+  END
+  v9.CheckScriptFailure(lines, 'E1314:')
+
+  lines =<< trim END
+      vim9script
+      class Not@working
+      endclass
+  END
+  v9.CheckScriptFailure(lines, 'E1315:')
+
+  lines =<< trim END
+      vim9script
+      abstract noclass Something
+      endclass
+  END
+  v9.CheckScriptFailure(lines, 'E475:')
+
+  lines =<< trim END
+      vim9script
+      abstract classy Something
+      endclass
+  END
+  v9.CheckScriptFailure(lines, 'E475:')
+
+  lines =<< trim END
+      vim9script
+      class Something
+      endcl
+  END
+  v9.CheckScriptFailure(lines, 'E1065:')
+
+  lines =<< trim END
+      vim9script
+      class Something
+      endclass school's out 
+  END
+  v9.CheckScriptFailure(lines, 'E488:')
+
+  lines =<< trim END
+      vim9script
+      class Something
+      endclass | echo 'done'
+  END
+  v9.CheckScriptFailure(lines, 'E488:')
+
+  lines =<< trim END
+      vim9script
+      class Something
+        this
+      endclass
+  END
+  v9.CheckScriptFailure(lines, 'E1317:')
+
+  lines =<< trim END
+      vim9script
+      class Something
+        this.
+      endclass
+  END
+  v9.CheckScriptFailure(lines, 'E1317:')
+
+  lines =<< trim END
+      vim9script
+      class Something
+        this .count
+      endclass
+  END
+  v9.CheckScriptFailure(lines, 'E1317:')
+
+  lines =<< trim END
+      vim9script
+      class Something
+        this. count
+      endclass
+  END
+  v9.CheckScriptFailure(lines, 'E1317:')
+
+  lines =<< trim END
+      vim9script
+      class Something
+        this.count: number
+        that.count
+      endclass
+  END
+  v9.CheckScriptFailure(lines, 'E1318: Not a valid command in a class: that.count')
+
+  lines =<< trim END
+      vim9script
+      class Something
+        this.count
+      endclass
+  END
+  v9.CheckScriptFailure(lines, 'E1022:')
+
+  lines =<< trim END
+      vim9script
+      class Something
+        this.count : number
+      endclass
+  END
+  v9.CheckScriptFailure(lines, 'E1059:')
+
+  lines =<< trim END
+      vim9script
+      class Something
+        this.count:number
+      endclass
+  END
+  v9.CheckScriptFailure(lines, 'E1069:')
+
+  lines =<< trim END
+      vim9script
+
+      class TextPosition
+        this.lnum: number
+	this.col: number
+      endclass
+
+      # # FIXME: this works but leaks memory
+      # # use the automatically generated new() method
+      # var pos = TextPosition.new(2, 12)
+      # assert_equal(2, pos.lnum)
+      # assert_equal(12, pos.col)
+  END
+  v9.CheckScriptSuccess(lines)
+enddef
+
+
+" vim: ts=8 sw=2 sts=2 expandtab tw=80 fdm=marker
diff --git a/src/testing.c b/src/testing.c
index d76d098ee0..74b6b0e81b 100644
--- a/src/testing.c
+++ b/src/testing.c
@@ -1101,6 +1101,8 @@ f_test_refcount(typval_T *argvars, typval_T *rettv)
 	case VAR_SPECIAL:
 	case VAR_STRING:
 	case VAR_INSTR:
+	case VAR_CLASS:
+	case VAR_OBJECT:
 	    break;
 	case VAR_JOB:
 #ifdef FEAT_JOB_CHANNEL
diff --git a/src/typval.c b/src/typval.c
index b1a0060467..6faebe4015 100644
--- a/src/typval.c
+++ b/src/typval.c
@@ -84,6 +84,13 @@ free_tv(typval_T *varp)
 		channel_unref(varp->vval.v_channel);
 		break;
 #endif
+	    case VAR_CLASS:
+		class_unref(varp);
+		break;
+	    case VAR_OBJECT:
+		object_unref(varp->vval.v_object);
+		break;
+
 	    case VAR_NUMBER:
 	    case VAR_FLOAT:
 	    case VAR_ANY:
@@ -153,6 +160,12 @@ clear_tv(typval_T *varp)
 	    case VAR_INSTR:
 		VIM_CLEAR(varp->vval.v_instr);
 		break;
+	    case VAR_CLASS:
+		class_unref(varp);
+		break;
+	    case VAR_OBJECT:
+		object_unref(varp->vval.v_object);
+		break;
 	    case VAR_UNKNOWN:
 	    case VAR_ANY:
 	    case VAR_VOID:
@@ -234,6 +247,12 @@ tv_get_bool_or_number_chk(typval_T *varp, int *denote, int want_bool)
 	case VAR_BLOB:
 	    emsg(_(e_using_blob_as_number));
 	    break;
+	case VAR_CLASS:
+	    emsg(_(e_using_class_as_number));
+	    break;
+	case VAR_OBJECT:
+	    emsg(_(e_using_object_as_number));
+	    break;
 	case VAR_VOID:
 	    emsg(_(e_cannot_use_void_value));
 	    break;
@@ -333,6 +352,12 @@ tv_get_float_chk(typval_T *varp, int *error)
 	case VAR_BLOB:
 	    emsg(_(e_using_blob_as_float));
 	    break;
+	case VAR_CLASS:
+	    emsg(_(e_using_class_as_float));
+	    break;
+	case VAR_OBJECT:
+	    emsg(_(e_using_object_as_float));
+	    break;
 	case VAR_VOID:
 	    emsg(_(e_cannot_use_void_value));
 	    break;
@@ -1029,6 +1054,12 @@ tv_get_string_buf_chk_strict(typval_T *varp, char_u *buf, int strict)
 	case VAR_BLOB:
 	    emsg(_(e_using_blob_as_string));
 	    break;
+	case VAR_CLASS:
+	    emsg(_(e_using_class_as_string));
+	    break;
+	case VAR_OBJECT:
+	    emsg(_(e_using_object_as_string));
+	    break;
 	case VAR_JOB:
 #ifdef FEAT_JOB_CHANNEL
 	    if (in_vim9script())
@@ -1158,6 +1189,14 @@ copy_tv(typval_T *from, typval_T *to)
 	    to->vval.v_instr = from->vval.v_instr;
 	    break;
 
+	case VAR_CLASS:
+	    copy_class(from, to);
+	    break;
+
+	case VAR_OBJECT:
+	    copy_object(from, to);
+	    break;
+
 	case VAR_STRING:
 	case VAR_FUNC:
 	    if (from->vval.v_string == NULL)
@@ -1878,6 +1917,13 @@ tv_equal(
 	case VAR_INSTR:
 	    return tv1->vval.v_instr == tv2->vval.v_instr;
 
+	case VAR_CLASS:
+	    return tv1->vval.v_class == tv2->vval.v_class;
+
+	case VAR_OBJECT:
+	    // TODO: compare values
+	    return tv1->vval.v_object == tv2->vval.v_object;
+
 	case VAR_PARTIAL:
 	    return tv1->vval.v_partial == tv2->vval.v_partial;
 
diff --git a/src/userfunc.c b/src/userfunc.c
index 492c6721bc..5db0b709c2 100644
--- a/src/userfunc.c
+++ b/src/userfunc.c
@@ -214,6 +214,8 @@ get_function_args(
     garray_T	*default_args,
     int		skip,
     exarg_T	*eap,		// can be NULL
+    class_T	*class_arg,
+    garray_T	*newlines,	// function body lines
     garray_T	*lines_to_free)
 {
     int		mustend = FALSE;
@@ -292,6 +294,51 @@ get_function_args(
 		}
 	    }
 	}
+	else if (class_arg != NULL && STRNCMP(p, "this.", 5) == 0)
+	{
+	    // this.memberName
+	    p += 5;
+	    arg = p;
+	    while (ASCII_ISALNUM(*p) || *p == '_')
+		++p;
+
+	    // TODO: check the argument is indeed a member
+	    if (newargs != NULL && ga_grow(newargs, 1) == FAIL)
+		return FAIL;
+	    if (newargs != NULL)
+	    {
+		((char_u **)(newargs->ga_data))[newargs->ga_len] =
+						    vim_strnsave(arg, p - arg);
+		newargs->ga_len++;
+
+		if (argtypes != NULL && ga_grow(argtypes, 1) == OK)
+		{
+		    // TODO: use the actual type
+		    ((char_u **)argtypes->ga_data)[argtypes->ga_len++] =
+						  vim_strsave((char_u *)"any");
+
+		    // Add a line to the function body for the assignment.
+		    if (ga_grow(newlines, 1) == OK)
+		    {
+			// "this.name = name"
+			int len = 5 + (p - arg) + 3 + (p - arg) + 1;
+			char_u *assignment = alloc(len);
+			if (assignment != NULL)
+			{
+			    c = *p;
+			    *p = NUL;
+			    vim_snprintf((char *)assignment, len,
+						     "this.%s = %s", arg, arg);
+			    *p = c;
+			    ((char_u **)(newlines->ga_data))[
+					      newlines->ga_len++] = assignment;
+			}
+		    }
+		}
+	    }
+	    if (*p == ',')
+		++p;
+	}
 	else
 	{
 	    char_u *np;
@@ -1389,7 +1436,7 @@ get_lambda_tv(
     s = *arg + 1;
     ret = get_function_args(&s, equal_arrow ? ')' : '-', NULL,
 	    types_optional ? &argtypes : NULL, types_optional, evalarg,
-					NULL, &default_args, TRUE, NULL, NULL);
+			    NULL, &default_args, TRUE, NULL, NULL, NULL, NULL);
     if (ret == FAIL || skip_arrow(s, equal_arrow, &ret_type, NULL) == NULL)
     {
 	if (types_optional)
@@ -1406,7 +1453,7 @@ get_lambda_tv(
     ret = get_function_args(arg, equal_arrow ? ')' : '-', pnewargs,
 	    types_optional ? &argtypes : NULL, types_optional, evalarg,
 					    &varargs, &default_args,
-					    FALSE, NULL, NULL);
+					    FALSE, NULL, NULL, NULL, NULL);
     if (ret == FAIL
 		  || (s = skip_arrow(*arg, equal_arrow, &ret_type,
 		equal_arrow || vim9script ? &white_error : NULL)) == NULL)
@@ -1733,7 +1780,7 @@ emsg_funcname(char *ermsg, char_u *name)
  * Return them in "*argvars[MAX_FUNC_ARGS + 1]" and the count in "argcount".
  * On failure FAIL is returned but the "argvars[argcount]" are still set.
  */
-    static int
+    int
 get_func_arguments(
 	char_u	    **arg,
 	evalarg_T   *evalarg,
@@ -1809,7 +1856,7 @@ get_func_tv(
     funcexe_T	*funcexe)	// various values
 {
     char_u	*argp;
-    int		ret = OK;
+    int		ret;
     typval_T	argvars[MAX_FUNC_ARGS + 1];	// vars for arguments
     int		argcount = 0;			// number of arguments found
     int		vim9script = in_vim9script();
@@ -4370,10 +4417,15 @@ list_functions(regmatch_T *regmatch)
  * When "name_arg" is not NULL this is a nested function, using "name_arg" for
  * the function name.
  * "lines_to_free" is a list of strings to be freed later.
+ * If "class_arg" is not NULL then the function is defi