patch 8.2.3725: cannot use a lambda for 'completefunc' and 'omnifunc'

Problem:    Cannot use a lambda for 'completefunc' and 'omnifunc'.
Solution:   Implement lambda support. (Yegappan Lakshmanan, closes #9257)

runtime/doc/options.txt

@@ -373,8 +373,8 @@ Note: In the future more global options can be made global-local.  Using
 
 						*option-value-function*
 Some options ('completefunc', 'imactivatefunc', 'imstatusfunc', 'omnifunc',
-'operatorfunc', 'quickfixtextfunc' and 'tagfunc') are set to a function name
-or a function reference or a lambda function.  Examples:
+'operatorfunc', 'quickfixtextfunc', 'tagfunc' and 'thesaurusfunc') are set to
+a function name or a function reference or a lambda function.  Examples:
 >
 	set opfunc=MyOpFunc
 	set opfunc=function('MyOpFunc')
@@ -1939,7 +1939,9 @@ A jump table for the options with a short description can be found at |Q_op|.
 	This option specifies a function to be used for Insert mode completion
 	with CTRL-X CTRL-U. |i_CTRL-X_CTRL-U|
 	See |complete-functions| for an explanation of how the function is
-	invoked and what it should return.
+	invoked and what it should return.  The value can be the name of a
+	function, a |lambda| or a |Funcref|. See |option-value-function| for
+	more information.
 	This option cannot be set from a |modeline| or in the |sandbox|, for
 	security reasons.
 
@@ -5616,7 +5618,9 @@ A jump table for the options with a short description can be found at |Q_op|.
 	This option specifies a function to be used for Insert mode omni
 	completion with CTRL-X CTRL-O. |i_CTRL-X_CTRL-O|
 	See |complete-functions| for an explanation of how the function is
-	invoked and what it should return.
+	invoked and what it should return.  The value can be the name of a
+	function, a |lambda| or a |Funcref|. See |option-value-function| for
+	more information.
 	This option is usually set by a filetype plugin:
 	|:filetype-plugin-on|
 	This option cannot be set from a |modeline| or in the |sandbox|, for
@@ -8075,6 +8079,8 @@ A jump table for the options with a short description can be found at |Q_op|.
 			feature}
 	This option specifies a function to be used for thesaurus completion
 	with CTRL-X CTRL-T. |i_CTRL-X_CTRL-T| See |compl-thesaurusfunc|.
+	The value can be the name of a function, a |lambda| or a |Funcref|.
+	See |option-value-function| for more information.
 
 	This option cannot be set from a |modeline| or in the |sandbox|, for
 	security reasons.

src/buffer.c

@@ -2326,8 +2326,11 @@ free_buf_options(
     clear_string_option(&buf->b_p_cpt);
 #ifdef FEAT_COMPL_FUNC
     clear_string_option(&buf->b_p_cfu);
+    free_callback(&buf->b_cfu_cb);
     clear_string_option(&buf->b_p_ofu);
+    free_callback(&buf->b_ofu_cb);
     clear_string_option(&buf->b_p_tsrfu);
+    free_callback(&buf->b_tsrfu_cb);
 #endif
 #ifdef FEAT_QUICKFIX
     clear_string_option(&buf->b_p_gp);

src/insexpand.c

@@ -2237,6 +2237,113 @@ ins_compl_next_buf(buf_T *buf, int flag)
 }
 
 #ifdef FEAT_COMPL_FUNC
+
+# ifdef FEAT_EVAL
+static callback_T cfu_cb;	    // 'completefunc' callback function
+static callback_T ofu_cb;	    // 'omnifunc' callback function
+static callback_T tsrfu_cb;	    // 'thesaurusfunc' callback function
+# endif
+
+/*
+ * Copy a global callback function to a buffer local callback.
+ */
+    static void
+copy_global_to_buflocal_cb(callback_T *globcb, callback_T *bufcb)
+{
+    free_callback(bufcb);
+    if (globcb->cb_name != NULL && *globcb->cb_name != NUL)
+	copy_callback(bufcb, globcb);
+}
+
+/*
+ * Parse the 'completefunc' option value and set the callback function.
+ * Invoked when the 'completefunc' option is set. The option value can be a
+ * name of a function (string), or function(<name>) or funcref(<name>) or a
+ * lambda expression.
+ */
+    int
+set_completefunc_option(void)
+{
+    int	retval;
+
+    retval = option_set_callback_func(curbuf->b_p_cfu, &cfu_cb);
+    if (retval == OK)
+	set_buflocal_cfu_callback(curbuf);
+
+    return retval;
+}
+
+/*
+ * Copy the global 'completefunc' callback function to the buffer-local
+ * 'completefunc' callback for 'buf'.
+ */
+    void
+set_buflocal_cfu_callback(buf_T *buf UNUSED)
+{
+# ifdef FEAT_EVAL
+    copy_global_to_buflocal_cb(&cfu_cb, &buf->b_cfu_cb);
+# endif
+}
+
+/*
+ * Parse the 'omnifunc' option value and set the callback function.
+ * Invoked when the 'omnifunc' option is set. The option value can be a
+ * name of a function (string), or function(<name>) or funcref(<name>) or a
+ * lambda expression.
+ */
+    int
+set_omnifunc_option(void)
+{
+    int	retval;
+
+    retval = option_set_callback_func(curbuf->b_p_ofu, &ofu_cb);
+    if (retval == OK)
+	set_buflocal_ofu_callback(curbuf);
+
+    return retval;
+}
+
+/*
+ * Copy the global 'omnifunc' callback function to the buffer-local 'omnifunc'
+ * callback for 'buf'.
+ */
+    void
+set_buflocal_ofu_callback(buf_T *buf UNUSED)
+{
+# ifdef FEAT_EVAL
+    copy_global_to_buflocal_cb(&ofu_cb, &buf->b_ofu_cb);
+# endif
+}
+
+/*
+ * Parse the 'thesaurusfunc' option value and set the callback function.
+ * Invoked when the 'thesaurusfunc' option is set. The option value can be a
+ * name of a function (string), or function(<name>) or funcref(<name>) or a
+ * lambda expression.
+ */
+    int
+set_thesaurusfunc_option(void)
+{
+    int	retval;
+
+    if (*curbuf->b_p_tsrfu != NUL)
+    {
+	// buffer-local option set
+	free_callback(&curbuf->b_tsrfu_cb);
+	retval = option_set_callback_func(curbuf->b_p_tsrfu,
+							&curbuf->b_tsrfu_cb);
+    }
+    else
+    {
+	// global option set
+	free_callback(&tsrfu_cb);
+	retval = option_set_callback_func(p_tsrfu, &tsrfu_cb);
+    }
+
+    return retval;
+}
+
+
 /*
  * Get the user-defined completion function name for completion 'type'
  */
@@ -2256,6 +2363,20 @@ get_complete_funcname(int type)
     }
 }
 
+/*
+ * Get the callback to use for insert mode completion.
+ */
+    callback_T *
+get_insert_callback(int type)
+{
+    if (type == CTRL_X_FUNCTION)
+	return &curbuf->b_cfu_cb;
+    if (type == CTRL_X_OMNI)
+	return &curbuf->b_ofu_cb;
+    // CTRL_X_THESAURUS
+    return (*curbuf->b_p_tsrfu != NUL) ? &curbuf->b_tsrfu_cb : &tsrfu_cb;
+}
+
 /*
  * Execute user defined complete function 'completefunc', 'omnifunc' or
  * 'thesaurusfunc', and get matches in "matches".
@@ -2269,8 +2390,10 @@ expand_by_function(int type, char_u *base)
     typval_T	args[3];
     char_u	*funcname;
     pos_T	pos;
+    callback_T	*cb;
     typval_T	rettv;
     int		save_State = State;
+    int		retval;
 
     funcname = get_complete_funcname(type);
     if (*funcname == NUL)
@@ -2289,8 +2412,11 @@ expand_by_function(int type, char_u *base)
     // Insert mode in another buffer.
     ++textwinlock;
 
+    cb = get_insert_callback(type);
+    retval = call_callback(cb, 0, &rettv, 2, args);
+
     // Call a function, which returns a list or dict.
-    if (call_vim_function(funcname, 2, args, &rettv) == OK)
+    if (retval == OK)
     {
 	switch (rettv.v_type)
 	{
@@ -3971,6 +4097,7 @@ ins_complete(int c, int enable_pum)
 	    char_u	*funcname;
 	    pos_T	pos;
 	    int		save_State = State;
+	    callback_T	*cb;
 
 	    // Call 'completefunc' or 'omnifunc' and get pattern length as a
 	    // string
@@ -3991,7 +4118,8 @@ ins_complete(int c, int enable_pum)
 	    args[2].v_type = VAR_UNKNOWN;
 	    pos = curwin->w_cursor;
 	    ++textwinlock;
-	    col = call_func_retnr(funcname, 2, args);
+	    cb = get_insert_callback(ctrl_x_mode);
+	    col = call_callback_retnr(cb, 2, args);
 	    --textwinlock;
 
 	    State = save_State;
@@ -4339,6 +4467,11 @@ quote_meta(char_u *dest, char_u *src, int len)
 free_insexpand_stuff(void)
 {
     VIM_CLEAR(compl_orig_text);
+# ifdef FEAT_EVAL
+    free_callback(&cfu_cb);
+    free_callback(&ofu_cb);
+    free_callback(&tsrfu_cb);
+# endif
 }
 #endif
 

src/option.c

@@ -5927,13 +5927,15 @@ buf_copy_options(buf_T *buf, int flags)
 #ifdef FEAT_COMPL_FUNC
 	    buf->b_p_cfu = vim_strsave(p_cfu);
 	    COPY_OPT_SCTX(buf, BV_CFU);
+	    set_buflocal_cfu_callback(buf);
 	    buf->b_p_ofu = vim_strsave(p_ofu);
 	    COPY_OPT_SCTX(buf, BV_OFU);
+	    set_buflocal_ofu_callback(buf);
 #endif
 #ifdef FEAT_EVAL
 	    buf->b_p_tfu = vim_strsave(p_tfu);
 	    COPY_OPT_SCTX(buf, BV_TFU);
-	    buf_set_tfu_callback(buf);
+	    set_buflocal_tfu_callback(buf);
 #endif
 	    buf->b_p_sts = p_sts;
 	    COPY_OPT_SCTX(buf, BV_STS);

src/optionstr.c

@@ -2307,6 +2307,29 @@ did_set_string_option(
 # endif
 #endif
 
+#ifdef FEAT_COMPL_FUNC
+    // 'completefunc'
+    else if (gvarp == &p_cfu)
+    {
+	if (set_completefunc_option() == FAIL)
+	    errmsg = e_invarg;
+    }
+
+    // 'omnifunc'
+    else if (gvarp == &p_ofu)
+    {
+	if (set_omnifunc_option() == FAIL)
+	    errmsg = e_invarg;
+    }
+
+    // 'thesaurusfunc'
+    else if (gvarp == &p_tsrfu)
+    {
+	if (set_thesaurusfunc_option() == FAIL)
+	    errmsg = e_invarg;
+    }
+#endif
+
     // 'operatorfunc'
     else if (varp == &p_opfunc)
     {

src/proto/insexpand.pro

@@ -39,6 +39,12 @@ int ins_compl_bs(void);
 void ins_compl_addleader(int c);
 void ins_compl_addfrommatch(void);
 int ins_compl_prep(int c);
+int set_completefunc_option(void);
+void set_buflocal_cfu_callback(buf_T *buf);
+int set_omnifunc_option(void);
+void set_buflocal_ofu_callback(buf_T *buf);
+int set_thesaurusfunc_option(void);
+callback_T *get_insert_callback(int type);
 void f_complete(typval_T *argvars, typval_T *rettv);
 void f_complete_add(typval_T *argvars, typval_T *rettv);
 void f_complete_check(typval_T *argvars, typval_T *rettv);

src/proto/tag.pro

@@ -1,7 +1,7 @@
 /* tag.c */
 int set_tagfunc_option(void);
 void free_tagfunc_option(void);
-void buf_set_tfu_callback(buf_T *buf);
+void set_buflocal_tfu_callback(buf_T *buf);
 int do_tag(char_u *tag, int type, int count, int forceit, int verbose);
 void tag_freematch(void);
 void do_tags(exarg_T *eap);

src/proto/userfunc.pro

@@ -28,6 +28,7 @@ int builtin_function(char_u *name, int len);
 int func_call(char_u *name, typval_T *args, partial_T *partial, dict_T *selfdict, typval_T *rettv);
 int get_callback_depth(void);
 int call_callback(callback_T *callback, int len, typval_T *rettv, int argcount, typval_T *argvars);
+varnumber_T call_callback_retnr(callback_T *callback, int argcount, typval_T *argvars);
 void user_func_error(int error, char_u *name);
 int call_func(char_u *funcname, int len, typval_T *rettv, int argcount_in, typval_T *argvars_in, funcexe_T *funcexe);
 char_u *printable_func_name(ufunc_T *fp);

src/structs.h

@@ -2876,7 +2876,9 @@ struct file_buffer
 #endif
 #ifdef FEAT_COMPL_FUNC
     char_u	*b_p_cfu;	// 'completefunc'
+    callback_T	b_cfu_cb;	// 'completefunc' callback
     char_u	*b_p_ofu;	// 'omnifunc'
+    callback_T	b_ofu_cb;	// 'omnifunc' callback
 #endif
 #ifdef FEAT_EVAL
     char_u	*b_p_tfu;	// 'tagfunc' option value
@@ -2982,6 +2984,7 @@ struct file_buffer
     char_u	*b_p_tsr;	// 'thesaurus' local value
 #ifdef FEAT_COMPL_FUNC
     char_u	*b_p_tsrfu;	// 'thesaurusfunc' local value
+    callback_T	b_tsrfu_cb;	// 'thesaurusfunc' callback
 #endif
     long	b_p_ul;		// 'undolevels' local value
 #ifdef FEAT_PERSISTENT_UNDO

src/tag.c

@@ -115,7 +115,7 @@ static callback_T tfu_cb;	    // 'tagfunc' callback function
  * a function (string), or function(<name>) or funcref(<name>) or a lambda.
  */
     int
-set_tagfunc_option()
+set_tagfunc_option(void)
 {
 #ifdef FEAT_EVAL
     free_callback(&tfu_cb);
@@ -148,7 +148,7 @@ free_tagfunc_option(void)
  * callback for 'buf'.
  */
     void
-buf_set_tfu_callback(buf_T *buf UNUSED)
+set_buflocal_tfu_callback(buf_T *buf UNUSED)
 {
 #ifdef FEAT_EVAL
     free_callback(&buf->b_tfu_cb);