patch 8.2.1047: Vim9: script cannot use line continuation like :def functionv8.2.1047

Problem:    Vim9: script cannot use line continuation like in a :def function.
Solution:   Pass the getline function pointer to the eval() functions.  Use it
            for addition and multiplication operators.

15 files changed, 300 insertions, 111 deletions

diff --git a/src/dict.c b/src/dict.c
index 9d94261986..caa398deba 100644
--- a/src/dict.c
+++ b/src/dict.c
@@ -788,12 +788,14 @@ get_literal_key(char_u **arg, typval_T *tv)
 /*
  * Allocate a variable for a Dictionary and fill it from "*arg".
  * "literal" is TRUE for #{key: val}
+ * "flags" can have EVAL_EVALUATE and other EVAL_ flags.
  * Return OK or FAIL.  Returns NOTDONE for {expr}.
  */
     int
 eval_dict(char_u **arg, typval_T *rettv, int flags, int literal)
 {
     int		evaluate = flags & EVAL_EVALUATE;
+    evalarg_T	evalarg;
     dict_T	*d = NULL;
     typval_T	tvkey;
     typval_T	tv;
@@ -803,6 +805,9 @@ eval_dict(char_u **arg, typval_T *rettv, int flags, int literal)
     char_u	buf[NUMBUFLEN];
     int		vim9script = current_sctx.sc_version == SCRIPT_VERSION_VIM9;
 
+    CLEAR_FIELD(evalarg);
+    evalarg.eval_flags = flags;
+
     /*
      * First check if it's not a curly-braces thing: {expr}.
      * Must do this without evaluating, otherwise a function may be called
@@ -812,7 +817,7 @@ eval_dict(char_u **arg, typval_T *rettv, int flags, int literal)
      */
     if (!vim9script && *start != '}')
     {
-	if (eval1(&start, &tv, 0) == FAIL)	// recursive!
+	if (eval1(&start, &tv, NULL) == FAIL)	// recursive!
 	    return FAIL;
 	if (*start == '}')
 	    return NOTDONE;
@@ -832,7 +837,7 @@ eval_dict(char_u **arg, typval_T *rettv, int flags, int literal)
     {
 	if ((literal
 		? get_literal_key(arg, &tvkey)
-		: eval1(arg, &tvkey, flags)) == FAIL)	// recursive!
+		: eval1(arg, &tvkey, &evalarg)) == FAIL)	// recursive!
 	    goto failret;
 
 	if (**arg != ':')
@@ -854,7 +859,7 @@ eval_dict(char_u **arg, typval_T *rettv, int flags, int literal)
 	}
 
 	*arg = skipwhite(*arg + 1);
-	if (eval1(arg, &tv, flags) == FAIL)	// recursive!
+	if (eval1(arg, &tv, &evalarg) == FAIL)	// recursive!
 	{
 	    if (evaluate)
 		clear_tv(&tvkey);
diff --git a/src/eval.c b/src/eval.c
index 38afc24894..ffb69de8d2 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -45,12 +45,12 @@ typedef struct
 } forinfo_T;
 
 static int tv_op(typval_T *tv1, typval_T *tv2, char_u  *op);
-static int eval2(char_u **arg, typval_T *rettv, int flags);
-static int eval3(char_u **arg, typval_T *rettv, int flags);
-static int eval4(char_u **arg, typval_T *rettv, int flags);
-static int eval5(char_u **arg, typval_T *rettv, int flags);
-static int eval6(char_u **arg, typval_T *rettv, int flags, int want_string);
-static int eval7(char_u **arg, typval_T *rettv, int flags, int want_string);
+static int eval2(char_u **arg, typval_T *rettv, evalarg_T *evalarg);
+static int eval3(char_u **arg, typval_T *rettv, evalarg_T *evalarg);
+static int eval4(char_u **arg, typval_T *rettv, evalarg_T *evalarg);
+static int eval5(char_u **arg, typval_T *rettv, evalarg_T *evalarg);
+static int eval6(char_u **arg, typval_T *rettv, evalarg_T *evalarg, int want_string);
+static int eval7(char_u **arg, typval_T *rettv, evalarg_T *evalarg, int want_string);
 static int eval7_leader(typval_T *rettv, char_u *start_leader, char_u **end_leaderp);
 
 static int free_unref_items(int copyID);
@@ -169,7 +169,7 @@ eval_to_bool(
 
     if (skip)
 	++emsg_skip;
-    if (eval0(arg, &tv, nextcmd, skip ? 0 : EVAL_EVALUATE) == FAIL)
+    if (eval0(arg, &tv, nextcmd, skip ? NULL : &EVALARG_EVALUATE) == FAIL)
 	*error = TRUE;
     else
     {
@@ -197,7 +197,7 @@ eval1_emsg(char_u **arg, typval_T *rettv, int evaluate)
     int		did_emsg_before = did_emsg;
     int		called_emsg_before = called_emsg;
 
-    ret = eval1(arg, rettv, evaluate ? EVAL_EVALUATE : 0);
+    ret = eval1(arg, rettv, evaluate ? &EVALARG_EVALUATE : NULL);
     if (ret == FAIL)
     {
 	// Report the invalid expression unless the expression evaluation has
@@ -325,7 +325,8 @@ eval_to_string_skip(
 
     if (skip)
 	++emsg_skip;
-    if (eval0(arg, &tv, nextcmd, skip ? 0 : EVAL_EVALUATE) == FAIL || skip)
+    if (eval0(arg, &tv, nextcmd, skip ? NULL : &EVALARG_EVALUATE)
+							       == FAIL || skip)
 	retval = NULL;
     else
     {
@@ -348,7 +349,7 @@ skip_expr(char_u **pp)
     typval_T	rettv;
 
     *pp = skipwhite(*pp);
-    return eval1(pp, &rettv, 0);
+    return eval1(pp, &rettv, NULL);
 }
 
 /*
@@ -370,7 +371,7 @@ eval_to_string(
     char_u	numbuf[NUMBUFLEN];
 #endif
 
-    if (eval0(arg, &tv, nextcmd, EVAL_EVALUATE) == FAIL)
+    if (eval0(arg, &tv, nextcmd, &EVALARG_EVALUATE) == FAIL)
 	retval = NULL;
     else
     {
@@ -440,7 +441,7 @@ eval_to_number(char_u *expr)
 
     ++emsg_off;
 
-    if (eval1(&p, &rettv, EVAL_EVALUATE) == FAIL)
+    if (eval1(&p, &rettv, &EVALARG_EVALUATE) == FAIL)
 	retval = -1;
     else
     {
@@ -463,7 +464,7 @@ eval_expr(char_u *arg, char_u **nextcmd)
     typval_T	*tv;
 
     tv = ALLOC_ONE(typval_T);
-    if (tv != NULL && eval0(arg, tv, nextcmd, EVAL_EVALUATE) == FAIL)
+    if (tv != NULL && eval0(arg, tv, nextcmd, &EVALARG_EVALUATE) == FAIL)
 	VIM_CLEAR(tv);
 
     return tv;
@@ -588,7 +589,7 @@ eval_foldexpr(char_u *arg, int *cp)
 	++sandbox;
     ++textwinlock;
     *cp = NUL;
-    if (eval0(arg, &tv, NULL, EVAL_EVALUATE) == FAIL)
+    if (eval0(arg, &tv, NULL, &EVALARG_EVALUATE) == FAIL)
 	retval = 0;
     else
     {
@@ -776,7 +777,7 @@ get_lval(
 	    else
 	    {
 		empty1 = FALSE;
-		if (eval1(&p, &var1, EVAL_EVALUATE) == FAIL)  // recursive!
+		if (eval1(&p, &var1, &EVALARG_EVALUATE) == FAIL)  // recursive!
 		    return NULL;
 		if (tv_get_string_chk(&var1) == NULL)
 		{
@@ -814,7 +815,7 @@ get_lval(
 		{
 		    lp->ll_empty2 = FALSE;
 		    // recursive!
-		    if (eval1(&p, &var2, EVAL_EVALUATE) == FAIL)
+		    if (eval1(&p, &var2, &EVALARG_EVALUATE) == FAIL)
 		    {
 			clear_tv(&var1);
 			return NULL;
@@ -1424,7 +1425,10 @@ eval_for_line(
     char_u	*expr;
     typval_T	tv;
     list_T	*l;
+    evalarg_T	evalarg;
 
+    CLEAR_FIELD(evalarg);
+    evalarg.eval_flags = skip ? 0 : EVAL_EVALUATE;
     *errp = TRUE;	// default: there is an error
 
     fi = ALLOC_CLEAR_ONE(forinfo_T);
@@ -1444,8 +1448,7 @@ eval_for_line(
 
     if (skip)
 	++emsg_skip;
-    if (eval0(skipwhite(expr + 2), &tv, nextcmdp, skip ? 0 : EVAL_EVALUATE)
-									 == OK)
+    if (eval0(skipwhite(expr + 2), &tv, nextcmdp, &evalarg) == OK)
     {
 	*errp = FALSE;
 	if (!skip)
@@ -1764,6 +1767,35 @@ eval_func(
 }
 
 /*
+ * If inside Vim9 script, "arg" points to the end of a line (ignoring comments)
+ * and there is a next line, return the next line (skipping blanks) and set
+ * "getnext".
+ * Otherwise just return "arg" unmodified and set "getnext" to FALSE.
+ * "arg" must point somewhere inside a line, not at the start.
+ */
+    static char_u *
+eval_next_non_blank(char_u *arg, evalarg_T *evalarg, int *getnext)
+{
+    *getnext = FALSE;
+    if (current_sctx.sc_version == SCRIPT_VERSION_VIM9
+	    && evalarg != NULL
+	    && evalarg->eval_cookie != NULL
+	    && (*arg == NUL || (VIM_ISWHITE(arg[-1])
+					     && (*arg == '"' || *arg == '#')))
+	    && source_nextline(evalarg->eval_cookie) != NULL)
+    {
+	char_u *p = source_nextline(evalarg->eval_cookie);
+
+	if (p != NULL)
+	{
+	    *getnext = TRUE;
+	    return skipwhite(p);
+	}
+    }
+    return arg;
+}
+
+/*
  * The "evaluate" argument: When FALSE, the argument is only parsed but not
  * executed.  The function may return OK, but the rettv will be of type
  * VAR_UNKNOWN.  The function still returns FAIL for a syntax error.
@@ -1774,7 +1806,7 @@ eval_func(
  * This calls eval1() and handles error message and nextcmd.
  * Put the result in "rettv" when returning OK and "evaluate" is TRUE.
  * Note: "rettv.v_lock" is not set.
- * "flags" has EVAL_EVALUATE and similar flags.
+ * "evalarg" can be NULL, EVALARG_EVALUATE or a pointer.
  * Return OK or FAIL.
  */
     int
@@ -1782,15 +1814,16 @@ eval0(
     char_u	*arg,
     typval_T	*rettv,
     char_u	**nextcmd,
-    int		flags)
+    evalarg_T	*evalarg)
 {
     int		ret;
     char_u	*p;
     int		did_emsg_before = did_emsg;
     int		called_emsg_before = called_emsg;
+    int		flags = evalarg == NULL ? 0 : evalarg->eval_flags;
 
     p = skipwhite(arg);
-    ret = eval1(&p, rettv, flags);
+    ret = eval1(&p, rettv, evalarg);
     if (ret == FAIL || !ends_excmd2(arg, p))
     {
 	if (ret != FAIL)
@@ -1826,23 +1859,36 @@ eval0(
  * Return OK or FAIL.
  */
     int
-eval1(char_u **arg, typval_T *rettv, int flags)
+eval1(char_u **arg, typval_T *rettv, evalarg_T *evalarg)
 {
-    int		result;
-    typval_T	var2;
-
     /*
      * Get the first variable.
      */
-    if (eval2(arg, rettv, flags) == FAIL)
+    if (eval2(arg, rettv, evalarg) == FAIL)
 	return FAIL;
 
     if ((*arg)[0] == '?')
     {
-	int evaluate = flags & EVAL_EVALUATE;
+	int		result;
+	typval_T	var2;
+	evalarg_T	nested_evalarg;
+	int		orig_flags;
+
+	if (evalarg == NULL)
+	{
+	    CLEAR_FIELD(nested_evalarg);
+	    orig_flags = 0;
+	}
+	else
+	{
+	    nested_evalarg = *evalarg;
+	    orig_flags = evalarg->eval_flags;
+	}
+
+	int evaluate = nested_evalarg.eval_flags & EVAL_EVALUATE;
 
 	result = FALSE;
-	if (flags & EVAL_EVALUATE)
+	if (evaluate)
 	{
 	    int		error = FALSE;
 
@@ -1857,7 +1903,9 @@ eval1(char_u **arg, typval_T *rettv, int flags)
 	 * Get the second variable.  Recursive!
 	 */
 	*arg = skipwhite(*arg + 1);
-	if (eval1(arg, rettv, result ? flags : flags & ~EVAL_EVALUATE) == FAIL)
+	nested_evalarg.eval_flags = result ? orig_flags
+						 : orig_flags & ~EVAL_EVALUATE;
+	if (eval1(arg, rettv, &nested_evalarg) == FAIL)
 	    return FAIL;
 
 	/*
@@ -1875,7 +1923,9 @@ eval1(char_u **arg, typval_T *rettv, int flags)
 	 * Get the third variable.  Recursive!
 	 */
 	*arg = skipwhite(*arg + 1);
-	if (eval1(arg, &var2, !result ? flags : flags & ~EVAL_EVALUATE) == FAIL)
+	nested_evalarg.eval_flags = !result ? orig_flags
+						 : orig_flags & ~EVAL_EVALUATE;
+	if (eval1(arg, &var2, &nested_evalarg) == FAIL)
 	{
 	    if (evaluate && result)
 		clear_tv(rettv);
@@ -1898,7 +1948,7 @@ eval1(char_u **arg, typval_T *rettv, int flags)
  * Return OK or FAIL.
  */
     static int
-eval2(char_u **arg, typval_T *rettv, int flags)
+eval2(char_u **arg, typval_T *rettv, evalarg_T *evalarg)
 {
     typval_T	var2;
     long	result;
@@ -1908,7 +1958,7 @@ eval2(char_u **arg, typval_T *rettv, int flags)
     /*
      * Get the first variable.
      */
-    if (eval3(arg, rettv, flags) == FAIL)
+    if (eval3(arg, rettv, evalarg) == FAIL)
 	return FAIL;
 
     /*
@@ -1918,7 +1968,22 @@ eval2(char_u **arg, typval_T *rettv, int flags)
     result = FALSE;
     while ((*arg)[0] == '|' && (*arg)[1] == '|')
     {
-	int evaluate = flags & EVAL_EVALUATE;
+	evalarg_T   nested_evalarg;
+	int	    evaluate;
+	int	    orig_flags;
+
+	if (evalarg == NULL)
+	{
+	    CLEAR_FIELD(nested_evalarg);
+	    orig_flags = 0;
+	    evaluate = FALSE;
+	}
+	else
+	{
+	    nested_evalarg = *evalarg;
+	    orig_flags = evalarg->eval_flags;
+	    evaluate = orig_flags & EVAL_EVALUATE;
+	}
 
 	if (evaluate && first)
 	{
@@ -1934,8 +1999,9 @@ eval2(char_u **arg, typval_T *rettv, int flags)
 	 * Get the second variable.
 	 */
 	*arg = skipwhite(*arg + 2);
-	if (eval3(arg, &var2, !result ? flags : flags & ~EVAL_EVALUATE)
-								       == FAIL)
+	nested_evalarg.eval_flags = !result ? orig_flags
+						 : orig_flags & ~EVAL_EVALUATE;
+	if (eval3(arg, &var2, &nested_evalarg) == FAIL)
 	    return FAIL;
 
 	/*
@@ -1969,7 +2035,7 @@ eval2(char_u **arg, typval_T *rettv, int flags)
  * Return OK or FAIL.
  */
     static int
-eval3(char_u **arg, typval_T *rettv, int flags)
+eval3(char_u **arg, typval_T *rettv, evalarg_T *evalarg)
 {
     typval_T	var2;
     long	result;
@@ -1979,7 +2045,7 @@ eval3(char_u **arg, typval_T *rettv, int flags)
     /*
      * Get the first variable.
      */
-    if (eval4(arg, rettv, flags) == FAIL)
+    if (eval4(arg, rettv, evalarg) == FAIL)
 	return FAIL;
 
     /*
@@ -1989,8 +2055,22 @@ eval3(char_u **arg, typval_T *rettv, int flags)
     result = TRUE;
     while ((*arg)[0] == '&' && (*arg)[1] == '&')
     {
-	int evaluate = flags & EVAL_EVALUATE;
+	evalarg_T   nested_evalarg;
+	int	    orig_flags;
+	int	    evaluate;
 
+	if (evalarg == NULL)
+	{
+	    CLEAR_FIELD(nested_evalarg);
+	    orig_flags = 0;
+	    evaluate = FALSE;
+	}
+	else
+	{
+	    nested_evalarg = *evalarg;
+	    orig_flags = evalarg->eval_flags;
+	    evaluate = orig_flags & EVAL_EVALUATE;
+	}
 	if (evaluate && first)
 	{
 	    if (tv_get_number_chk(rettv, &error) == 0)
@@ -2005,7 +2085,9 @@ eval3(char_u **arg, typval_T *rettv, int flags)
 	 * Get the second variable.
 	 */
 	*arg = skipwhite(*arg + 2);
-	if (eval4(arg, &var2, result ? flags : flags & ~EVAL_EVALUATE) == FAIL)
+	nested_evalarg.eval_flags = result ? orig_flags
+						 : orig_flags & ~EVAL_EVALUATE;
+	if (eval4(arg, &var2, &nested_evalarg) == FAIL)
 	    return FAIL;
 
 	/*
@@ -2048,7 +2130,7 @@ eval3(char_u **arg, typval_T *rettv, int flags)
  * Return OK or FAIL.
  */
     static int
-eval4(char_u **arg, typval_T *rettv, int flags)
+eval4(char_u **arg, typval_T *rettv, evalarg_T *evalarg)
 {
     typval_T	var2;
     char_u	*p;
@@ -2060,7 +2142,7 @@ eval4(char_u **arg, typval_T *rettv, int flags)
     /*
      * Get the first variable.
      */
-    if (eval5(arg, rettv, flags) == FAIL)
+    if (eval5(arg, rettv, evalarg) == FAIL)
 	return FAIL;
 
     p = *arg;
@@ -2128,12 +2210,12 @@ eval4(char_u **arg, typval_T *rettv, int flags)
 	 * Get the second variable.
 	 */
 	*arg = skipwhite(p + len);
-	if (eval5(arg, &var2, flags) == FAIL)
+	if (eval5(arg, &var2, evalarg) == FAIL)
 	{
 	    clear_tv(rettv);
 	    return FAIL;
 	}
-	if (flags & EVAL_EVALUATE)
+	if (evalarg != NULL && (evalarg->eval_flags & EVAL_EVALUATE))
 	{
 	    int ret = typval_compare(rettv, &var2, type, ic);
 
@@ -2195,23 +2277,14 @@ eval_addlist(typval_T *tv1, typval_T *tv2)
  * Return OK or FAIL.
  */
     static int
-eval5(char_u **arg, typval_T *rettv, int flags)
+eval5(char_u **arg, typval_T *rettv, evalarg_T *evalarg)
 {
-    typval_T	var2;
-    int		op;
-    varnumber_T	n1, n2;
-#ifdef FEAT_FLOAT
-    float_T	f1 = 0, f2 = 0;
-#endif
-    char_u	*s1, *s2;
-    char_u	buf1[NUMBUFLEN], buf2[NUMBUFLEN];
-    char_u	*p;
-    int		concat;
+    int	evaluate = evalarg == NULL ? 0 : (evalarg->eval_flags & EVAL_EVALUATE);
 
     /*
      * Get the first variable.
      */
-    if (eval6(arg, rettv, flags, FALSE) == FAIL)
+    if (eval6(arg, rettv, evalarg, FALSE) == FAIL)
 	return FAIL;
 
     /*
@@ -2219,12 +2292,20 @@ eval5(char_u **arg, typval_T *rettv, int flags)
      */
     for (;;)
     {
+	int	    getnext;
+	char_u	    *p;
+	int	    op;
+	int	    concat;
+	typval_T    var2;
+
 	// "." is only string concatenation when scriptversion is 1
-	op = **arg;
-	concat = op == '.'
-			&& (*(*arg + 1) == '.' || current_sctx.sc_version < 2);
+	p = eval_next_non_blank(*arg, evalarg, &getnext);
+	op = *p;
+	concat = op == '.' && (*(p + 1) == '.' || current_sctx.sc_version < 2);
 	if (op != '+' && op != '-' && !concat)
 	    break;
+	if (getnext)
+	    *arg = skipwhite(getsourceline(0, evalarg->eval_cookie, 0, TRUE));
 
 	if ((op != '+' || (rettv->v_type != VAR_LIST
 						 && rettv->v_type != VAR_BLOB))
@@ -2240,7 +2321,7 @@ eval5(char_u **arg, typval_T *rettv, int flags)
 	    // we know that the first operand needs to be a string or number
 	    // without evaluating the 2nd operand.  So check before to avoid
 	    // side effects after an error.
-	    if ((flags & EVAL_EVALUATE) && tv_get_string_chk(rettv) == NULL)
+	    if (evaluate && tv_get_string_chk(rettv) == NULL)
 	    {
 		clear_tv(rettv);
 		return FAIL;
@@ -2253,21 +2334,23 @@ eval5(char_u **arg, typval_T *rettv, int flags)
 	if (op == '.' && *(*arg + 1) == '.')  // .. string concatenation
 	    ++*arg;
 	*arg = skipwhite(*arg + 1);
-	if (eval6(arg, &var2, flags, op == '.') == FAIL)
+	if (eval6(arg, &var2, evalarg, op == '.') == FAIL)
 	{
 	    clear_tv(rettv);
 	    return FAIL;
 	}
 
-	if (flags & EVAL_EVALUATE)
+	if (evaluate)
 	{
 	    /*
 	     * Compute the result.
 	     */
 	    if (op == '.')
 	    {
-		s1 = tv_get_string_buf(rettv, buf1);	// already checked
-		s2 = tv_get_string_buf_chk(&var2, buf2);
+		char_u	buf1[NUMBUFLEN], buf2[NUMBUFLEN];
+		char_u	*s1 = tv_get_string_buf(rettv, buf1);
+		char_u	*s2 = tv_get_string_buf_chk(&var2, buf2);
+
 		if (s2 == NULL)		// type error ?
 		{
 		    clear_tv(rettv);
@@ -2290,9 +2373,11 @@ eval5(char_u **arg, typval_T *rettv, int flags)
 	    }
 	    else
 	    {
-		int	    error = FALSE;
-
+		int		error = FALSE;
+		varnumber_T	n1, n2;
 #ifdef FEAT_FLOAT
+		float_T	    f1 = 0, f2 = 0;
+
 		if (rettv->v_type == VAR_FLOAT)
 		{
 		    f1 = rettv->vval.v_float;
@@ -2381,7 +2466,7 @@ eval5(char_u **arg, typval_T *rettv, int flags)
 eval6(
     char_u	**arg,
     typval_T	*rettv,
-    int		flags,
+    evalarg_T	*evalarg,
     int		want_string)  // after "." operator
 {
     typval_T	var2;
@@ -2396,7 +2481,7 @@ eval6(
     /*
      * Get the first variable.
      */
-    if (eval7(arg, rettv, flags, want_string) == FAIL)
+    if (eval7(arg, rettv, evalarg, want_string) == FAIL)
 	return FAIL;
 
     /*
@@ -2404,11 +2489,17 @@ eval6(
      */
     for (;;)
     {
-	op = **arg;
+	int	evaluate = evalarg == NULL ? 0
+				       : (evalarg->eval_flags & EVAL_EVALUATE);
+	int	getnext;
+
+	op = *eval_next_non_blank(*arg, evalarg, &getnext);
 	if (op != '*' && op != '/' && op != '%')
 	    break;
+	if (getnext)
+	    *arg = skipwhite(getsourceline(0, evalarg->eval_cookie, 0, TRUE));
 
-	if (flags & EVAL_EVALUATE)
+	if (evaluate)
 	{
 #ifdef FEAT_FLOAT
 	    if (rettv->v_type == VAR_FLOAT)
@@ -2431,10 +2522,10 @@ eval6(
 	 * Get the second variable.
 	 */
 	*arg = skipwhite(*arg + 1);
-	if (eval7(arg, &var2, flags, FALSE) == FAIL)
+	if (eval7(arg, &var2, evalarg, FALSE) == FAIL)
 	    return FAIL;
 
-	if (flags & EVAL_EVALUATE)
+	if (evaluate)
 	{
 #ifdef FEAT_FLOAT
 	    if (var2.v_type == VAR_FLOAT)
@@ -2551,10 +2642,12 @@ eval6(
 eval7(
     char_u	**arg,
     typval_T	*rettv,
-    int		flags,
+    evalarg_T	*evalarg,
     int		want_string)	// after "." operator
 {
-    int		evaluate = flags & EVAL_EVALUATE;
+    int		flags = evalarg == NULL ? 0 : evalarg->eval_flags;
+    int		evaluate = evalarg != NULL
+				      && (evalarg->eval_flags & EVAL_EVALUATE);
     int		len;
     char_u	*s;
     char_u	*start_leader, *end_leader;
@@ -2672,15 +2765,17 @@ eval7(
     /*
      * nested expression: (expression).
      */
-    case '(':	*arg = skipwhite(*arg + 1);
-		ret = eval1(arg, rettv, flags);	// recursive!
-		if (**arg == ')')
-		    ++*arg;
-		else if (ret == OK)
-		{
-		    emsg(_(e_missing_close));
-		    clear_tv(rettv);
-		    ret = FAIL;
+    case '(':	{
+		    *arg = skipwhite(*arg + 1);
+		    ret = eval1(arg, rettv, evalarg);	// recursive!
+		    if (**arg == ')')
+			++*arg;
+		    else if (ret == OK)
+		    {
+			emsg(_(e_missing_close));
+			clear_tv(rettv);
+			ret = FAIL;
+		    }
 		}
 		break;
 
@@ -3030,6 +3125,11 @@ eval_index(
     }
     else
     {
+	evalarg_T	evalarg;
+
+	CLEAR_FIELD(evalarg);
+	evalarg.eval_flags = flags;
+
 	/*
 	 * something[idx]
 	 *
@@ -3038,7 +3138,7 @@ eval_index(
 	*arg = skipwhite(*arg + 1);
 	if (**arg == ':')
 	    empty1 = TRUE;
-	else if (eval1(arg, &var1, flags) == FAIL)	// recursive!
+	else if (eval1(arg, &var1, &evalarg) == FAIL)	// recursive!
 	    return FAIL;
 	else if (evaluate && tv_get_string_chk(&var1) == NULL)
 	{
@@ -3056,7 +3156,7 @@ eval_index(
 	    *arg = skipwhite(*arg + 1);
 	    if (**arg == ']')
 		empty2 = TRUE;
-	    else if (eval1(arg, &var2, flags) == FAIL)	// recursive!
+	    else if (eval1(arg, &var2, &evalarg) == FAIL)	// recursive!
 	    {
 		if (!empty1)
 		    clear_tv(&var1);
@@ -4947,6 +5047,10 @@ ex_echo(exarg_T *eap)
     int		atstart = TRUE;
     int		did_emsg_before = did_emsg;
     int		called_emsg_before = called_emsg;
+    evalarg_T	evalarg;
+
+    CLEAR_FIELD(evalarg);
+    evalarg.eval_flags = eap->skip ? 0 : EVAL_EVALUATE;
 
     if (eap->skip)
 	++emsg_skip;
@@ -4957,7 +5061,7 @@ ex_echo(exarg_T *eap)
 	need_clr_eos = needclr;
 
 	p = arg;
-	if (eval1(&arg, &rettv, eap->skip ? 0 : EVAL_EVALUATE) == FAIL)
+	if (eval1(&arg, &rettv, &evalarg) == FAIL)
 	{
 	    /*
 	     * Report the invalid expression unless the expression evaluation
diff --git a/src/evalfunc.c b/src/evalfunc.c
index c4ae951b60..53584dc46a 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -2084,7 +2084,7 @@ f_eval(typval_T *argvars, typval_T *rettv)
 	s = skipwhite(s);
 
     p = s;
-    if (s == NULL || eval1(&s, rettv, EVAL_EVALUATE) == FAIL)
+    if (s == NULL || eval1(&s, rettv, &EVALARG_EVALUATE) == FAIL)
     {
 	if (p != NULL && !aborting())
 	    semsg(_(e_invexpr2), p);
diff --git a/src/evalvars.c b/src/evalvars.c
index b3e89150ad..35c9dcb73e 100644
--- a/src/evalvars.c
+++ b/src/evalvars.c
@@ -435,7 +435,7 @@ eval_spell_expr(char_u *badword, char_u *expr)
     if (p_verbose == 0)
 	++emsg_off;
 
-    if (eval1(&p, &rettv, EVAL_EVALUATE) == OK)
+    if (eval1(&p, &rettv, &EVALARG_EVALUATE) == OK)
     {
 	if (rettv.v_type != VAR_LIST)
 	    clear_tv(&rettv);
@@ -774,7 +774,7 @@ ex_let(exarg_T *eap)
     }
     else
     {
-	int eval_flags;
+	evalarg_T   evalarg;
 
 	rettv.v_type = VAR_UNKNOWN;
 	i = FAIL;
@@ -797,14 +797,17 @@ ex_let(exarg_T *eap)
 
 	    if (eap->skip)
 		++emsg_skip;
-	    eval_flags = eap->skip ? 0 : EVAL_EVALUATE;
-	    i = eval0(expr, &rettv, &eap->nextcmd, eval_flags);
+	    evalarg.eval_flags = eap->skip ? 0 : EVAL_EVALUATE;
+	    evalarg.eval_cookie = eap->getline == getsourceline
+							  ? eap->cookie : NULL;
+	    i = eval0(expr, &rettv, &eap->nextcmd, &evalarg);
+	    if (eap->skip)
+		--emsg_skip;
 	}
 	if (eap->skip)
 	{
 	    if (i != FAIL)
 		clear_tv(&rettv);
-	    --emsg_skip;
 	}
 	else if (i != FAIL)
 	{
diff --git a/src/ex_eval.c b/src/ex_eval.c
index a13f844b14..cb32bd0791 100644
--- a/src/ex_eval.c
+++ b/src/ex_eval.c
@@ -895,9 +895,12 @@ report_discard_pending(int pending, void *value)
 ex_eval(exarg_T *eap)
 {
     typval_T	tv;
+    evalarg_T	evalarg;
 
-    if (eval0(eap->arg, &tv, &eap->nextcmd, eap->skip ? 0 : EVAL_EVALUATE)
-									 == OK)
+    evalarg.eval_flags = eap->skip ? 0 : EVAL_EVALUATE;
+    evalarg.eval_cookie = eap->getline == getsourceline ? eap->cookie : NULL;
+
+    if (eval0(eap->arg, &tv, &eap->nextcmd, &evalarg) == OK)
 	clear_tv(&tv);
 }
 
diff --git a/src/globals.h b/src/globals.h
index cd15491173..8601e2b1e5 100644
--- a/src/globals.h
+++ b/src/globals.h
@@ -1880,6 +1880,9 @@ EXTERN char windowsVersion[20] INIT(= {0});
 
 // Used for lv_first in a non-materialized range() list.
 EXTERN listitem_T range_list_item;
+
+// Passed to an eval() function to enable evaluation.
+EXTERN evalarg_T EVALARG_EVALUATE INIT2(EVAL_EVALUATE, NULL);
 #endif
 
 #ifdef MSWIN
diff --git a/src/list.c b/src/list.c
index 130ab25251..c624003a21 100644
--- a/src/list.c
+++ b/src/list.c
@@ -1165,6 +1165,10 @@ get_list_tv(char_u **arg, typval_T *rettv, int flags, int do_error)
     list_T	*l = NULL;
     typval_T	tv;
     listitem_T	*item;
+    evalarg_T	evalarg;
+
+    CLEAR_FIELD(evalarg);
+    evalarg.eval_flags = flags;
 
     if (evaluate)
     {
@@ -1176,7 +1180,7 @@ get_list_tv(char_u **arg, typval_T *rettv, int flags, int do_error)
     *arg = skipwhite(*arg + 1);
     while (**arg != ']' && **arg != NUL)
     {
-	if (eval1(arg, &tv, flags) == FAIL)	// recursive!
+	if (eval1(arg, &tv, &evalarg) == FAIL)	// recursive!
 	    goto failret;
 	if (evaluate)
 	{
diff --git a/src/proto/eval.pro b/src/proto/eval.pro
index 57dd8387cd..4fb04eb1fc 100644
--- a/src/proto/eval.pro
+++ b/src/proto/eval.pro
@@ -26,8 +26,8 @@ int next_for_item(void *fi_void, char_u *arg);
 void free_for_info(void *fi_void);
 void set_context_for_expression(expand_T *xp, char_u *arg, cmdidx_T cmdidx);
 int pattern_match(char_u *pat, char_u *text, int ic);
-int eval0(char_u *arg, typval_T *rettv, char_u **nextcmd, int flags);
-int eval1(char_u **arg, typval_T *rettv, int flags);
+int eval0(char_u *arg, typval_T *rettv, char_u **nextcmd, evalarg_T *evalarg);
+int eval1(char_u **arg, typval_T *rettv, evalarg_T *evalarg_in);
 void eval_addblob(typval_T *tv1, typval_T *tv2);
 int eval_addlist(typval_T *tv1, typval_T *tv2);
 char_u *partial_name(partial_T *pt);
diff --git a/src/proto/scriptfile.pro b/src/proto/scriptfile.pro
index e2a267141a..b5b8aae936 100644
--- a/src/proto/scriptfile.pro
+++ b/src/proto/scriptfile.pro
@@ -22,6 +22,7 @@ void ex_options(exarg_T *eap);
 linenr_T *source_breakpoint(void *cookie);
 int *source_dbg_tick(void *cookie);
 int source_level(void *cookie);
+char_u *source_nextline(void *cookie);
 int do_source(char_u *fname, int check_other, int is_vimrc, int *ret_sid);
 void ex_scriptnames(exarg_T *eap);
 void scriptnames_slash_adjust(void);
diff --git a/src/scriptfile.c b/src/scriptfile.c
index caeab19285..9ffc66c1b1 100644
--- a/src/scriptfile.c
+++ b/src/scriptfile.c
@@ -1050,6 +1050,15 @@ source_level(void *cookie)
 {
     return ((struct source_cookie *)cookie)->level;
 }
+
+/*
+ * Return the readahead line.
+ */
+    char_u *
+source_nextline(void *cookie)
+{
+    return ((struct source_cookie *)cookie)->nextline;
+}
 #endif
 
 #if (defined(MSWIN) && defined(FEAT_CSCOPE)) || defined(HAVE_FD_CLOEXEC)
diff --git a/src/structs.h b/src/structs.h
index ce9dfbcbfd..3a9bbd33c6 100644
--- a/src/structs.h
+++ b/src/structs.h
@@ -1746,6 +1746,19 @@ typedef struct
 # endif
 } scriptitem_T;
 
+// Struct passed through eval() functions.
+// See EVALARG_EVALUATE for a fixed value with eval_flags set to EVAL_EVALUATE.
+typedef struct {
+    int		eval_flags;	// EVAL_ flag values below
+
+    // copied from exarg_T when "getline" is "getsourceline". Can be NULL.
+    void	*eval_cookie;	// argument for getline()
+} evalarg_T;
+
+// Flags for expression evaluation.
+#define EVAL_EVALUATE	    1	    // when missing don't actually evaluate
+#define EVAL_CONSTANT	    2	    // when not a constant return FAIL
+
 # ifdef FEAT_PROFILE
 /*
  * Struct used in sn_prl_ga for every line of a script.
diff --git a/src/testdir/test_vim9_expr.vim b/src/testdir/test_vim9_expr.vim
index 46034fb30a..b37f92fb6a 100644
--- a/src/testdir/test_vim9_expr.vim
+++ b/src/testdir/test_vim9_expr.vim
@@ -570,6 +570,26 @@ def Test_expr5()
   assert_equal(0z01ab01ab, g:ablob + g:ablob)
 enddef
 
+def Test_expr5_vim9script()
+  " only checks line continuation
+  let lines =<< trim END
+      vim9script
+      let var = 11
+      		+ 77
+		- 22
+      assert_equal(66, var)
+  END
+  CheckScriptSuccess(lines)
+
+  lines =<< trim END
+      vim9script
+      let var = 'one'
+      		.. 'two'
+      assert_equal('onetwo', var)
+  END
+  CheckScriptSuccess(lines)
+enddef
+
 def Test_expr5_float()
   if !has('float')
     MissingFeature 'float'
@@ -661,6 +681,26 @@ def Test_expr6()
   call CheckDefFailure(["let x = 6 * xxx"], 'E1001')
 enddef
 
+def Test_expr6_vim9script()
+  " only checks line continuation
+  let lines =<< trim END
+      vim9script
+      let var = 11
+      		* 22
+		/ 3
+      assert_equal(80, var)
+  END
+  CheckScriptSuccess(lines)
+
+  lines =<< trim END
+      vim9script
+      let var = 25
+      		% 10
+      assert_equal(5, var)
+  END
+  CheckScriptSuccess(lines)
+enddef
+
 def Test_expr6_float()
   if !has('float')
     MissingFeature 'float'
diff --git a/src/userfunc.c b/src/userfunc.c
index 8a1b9edda8..a27c68d041 100644
--- a/src/userfunc.c
+++ b/src/userfunc.c
@@ -239,7 +239,7 @@ get_function_args(
 		whitep = p;
 		p = skipwhite(p);
 		expr = p;
-		if (eval1(&p, &rettv, 0) != FAIL)
+		if (eval1(&p, &rettv, NULL) != FAIL)
 		{
 		    if (ga_grow(default_args, 1) == FAIL)
 			goto err_ret;
@@ -561,6 +561,10 @@ get_func_tv(
     int		ret = OK;
     typval_T	argvars[MAX_FUNC_ARGS + 1];	// vars for arguments
     int		argcount = 0;		// number of arguments found
+    evalarg_T	evalarg;
+
+    CLEAR_FIELD(evalarg);
+    evalarg.eval_flags = funcexe->evaluate ? EVAL_EVALUATE : 0;
 
     /*
      * Get the arguments.
@@ -572,8 +576,7 @@ get_func_tv(
 	argp = skipwhite(argp + 1);	    // skip the '(' or ','
 	if (*argp == ')' || *argp == ',' || *argp == NUL)
 	    break;
-	if (eval1(&argp, &argvars[argcount],
-				funcexe->evaluate ? EVAL_EVALUATE : 0) == FAIL)
+	if (eval1(&argp, &argvars[argcount], &evalarg) == FAIL)
 	{
 	    ret = FAIL;
 	    break;
@@ -1249,7 +1252,7 @@ call_user_func(
 
 		default_expr = ((char_u **)(fp->uf_def_args.ga_data))
 						 [ai + fp->uf_def_args.ga_len];
-		if (eval1(&default_expr, &def_rettv, EVAL_EVALUATE) == FAIL)
+		if (eval1(&default_expr, &def_rettv, &EVALARG_EVALUATE) == FAIL)
 		{
 		    default_arg_err = 1;
 		    break;
@@ -1394,7 +1397,7 @@ call_user_func(
 	// A Lambda always has the command "return {expr}".  It is much faster
 	// to evaluate {expr} directly.
 	++ex_nesting_level;
-	(void)eval1(&p, rettv, EVAL_EVALUATE);
+	(void)eval1(&p, rettv, &EVALARG_EVALUATE);
 	--ex_nesting_level;
     }
     else
@@ -3697,6 +3700,7 @@ ex_return(exarg_T *eap)
     char_u	*arg = eap->arg;
     typval_T	rettv;
     int		returning = FALSE;
+    evalarg_T	evalarg;
 
     if (current_funccal == NULL)
     {
@@ -3704,13 +3708,15 @@ ex_return(exarg_T *eap)
 	return;
     }
 
+    CLEAR_FIELD(evalarg);
+    evalarg.eval_flags = eap->skip ? 0 : EVAL_EVALUATE;
+
     if (eap->skip)