vim-patch:8.1.0902: incomplete set of assignment operators

Problem:    Incomplete set of assignment operators.
Solution:   Add /=, *= and %=. (Ozaki Kiichi, closes vim/vim#3931)
https://github.com/vim/vim/commit/ff697e6cef8ced7717a21fd525ab3200b2f1724f

4 files changed, 126 insertions, 30 deletions

diff --git a/runtime/doc/eval.txt b/runtime/doc/eval.txt
index c96f51772d..f035c754c0 100644
--- a/runtime/doc/eval.txt
+++ b/runtime/doc/eval.txt
@@ -9459,9 +9459,13 @@ This does NOT work: >
 			When the selected range of items is partly past the
 			end of the list, items will be added.
 
-					*:let+=* *:let-=* *:let.=* *E734*
+                                            *:let+=* *:let-=* *:letstar=*
+                                            *:let/=* *:let%=* *:let.=* *E734*
 :let {var} += {expr1}	Like ":let {var} = {var} + {expr1}".
 :let {var} -= {expr1}	Like ":let {var} = {var} - {expr1}".
+:let {var} *= {expr1}	Like ":let {var} = {var} * {expr1}".
+:let {var} /= {expr1}	Like ":let {var} = {var} / {expr1}".
+:let {var} %= {expr1}	Like ":let {var} = {var} % {expr1}".
 :let {var} .= {expr1}	Like ":let {var} = {var} . {expr1}".
 			These fail if {var} was not set yet and when the type
 			of {var} and {expr1} don't fit the operator.
diff --git a/src/nvim/eval.c b/src/nvim/eval.c
index deaed17926..7d7c2d3f33 100644
--- a/src/nvim/eval.c
+++ b/src/nvim/eval.c
@@ -1442,6 +1442,9 @@ int eval_foldexpr(char_u *arg, int *cp)
  * ":let var = expr"		assignment command.
  * ":let var += expr"		assignment command.
  * ":let var -= expr"		assignment command.
+ * ":let var *= expr"		assignment command.
+ * ":let var /= expr"		assignment command.
+ * ":let var %= expr"		assignment command.
  * ":let var .= expr"		assignment command.
  * ":let [var1, var2] = expr"	unpack list.
  */
@@ -1465,7 +1468,7 @@ void ex_let(exarg_T *eap)
     argend--;
   }
   expr = skipwhite(argend);
-  if (*expr != '=' && !(vim_strchr((char_u *)"+-.", *expr) != NULL
+  if (*expr != '=' && !(vim_strchr((char_u *)"+-*/%.", *expr) != NULL
                         && expr[1] == '=')) {
     // ":let" without "=": list variables
     if (*arg == '[') {
@@ -1488,8 +1491,8 @@ void ex_let(exarg_T *eap)
     op[0] = '=';
     op[1] = NUL;
     if (*expr != '=') {
-      if (vim_strchr((char_u *)"+-.", *expr) != NULL) {
-        op[0] = *expr;  // +=, -=, .=
+      if (vim_strchr((char_u *)"+-*/%.", *expr) != NULL) {
+        op[0] = *expr;  // +=, -=, *=, /=, %= or .=
       }
       expr = skipwhite(expr + 2);
     } else {
@@ -1864,7 +1867,7 @@ static char_u *ex_let_one(char_u *arg, typval_T *const tv,
     if (len == 0) {
       EMSG2(_(e_invarg2), name - 1);
     } else {
-      if (op != NULL && (*op == '+' || *op == '-')) {
+      if (op != NULL && vim_strchr((char_u *)"+-*/%", *op) != NULL) {
         EMSG2(_(e_letwrong), op);
       } else if (endchars != NULL
                  && vim_strchr(endchars, *skipwhite(arg)) == NULL) {
@@ -1927,10 +1930,12 @@ static char_u *ex_let_one(char_u *arg, typval_T *const tv,
           s = NULL;  // don't set the value
         } else {
           if (opt_type == 1) {  // number
-            if (*op == '+') {
-              n = numval + n;
-            } else {
-              n = numval - n;
+            switch (*op) {
+              case '+': n = numval + n; break;
+              case '-': n = numval - n; break;
+              case '*': n = numval * n; break;
+              case '/': n = numval / n; break;
+              case '%': n = numval % n; break;
             }
           } else if (opt_type == 0 && stringval != NULL) {  // string
             char *const oldstringval = stringval;
@@ -1951,7 +1956,7 @@ static char_u *ex_let_one(char_u *arg, typval_T *const tv,
   // ":let @r = expr": Set register contents.
   } else if (*arg == '@') {
     arg++;
-    if (op != NULL && (*op == '+' || *op == '-')) {
+    if (op != NULL && vim_strchr((char_u *)"+-*/%", *op) != NULL) {
       emsgf(_(e_letwrong), op);
     } else if (endchars != NULL
                && vim_strchr(endchars, *skipwhite(arg + 1)) == NULL) {
@@ -2350,7 +2355,8 @@ static void clear_lval(lval_T *lp)
 /*
  * Set a variable that was parsed by get_lval() to "rettv".
  * "endp" points to just after the parsed name.
- * "op" is NULL, "+" for "+=", "-" for "-=", "." for ".=" or "=" for "=".
+ * "op" is NULL, "+" for "+=", "-" for "-=", "*" for "*=", "/" for "/=",
+ * "%" for "%=", "." for ".=" or "=" for "=".
  */
 static void set_var_lval(lval_T *lp, char_u *endp, typval_T *rettv,
                          int copy, const char_u *op)
@@ -2365,7 +2371,7 @@ static void set_var_lval(lval_T *lp, char_u *endp, typval_T *rettv,
     if (op != NULL && *op != '=') {
       typval_T tv;
 
-      // handle +=, -= and .=
+      // handle +=, -=, *=, /=, %= and .=
       di = NULL;
       if (get_var_tv((const char *)lp->ll_name, (int)STRLEN(lp->ll_name),
                      &tv, &di, true, false) == OK) {
diff --git a/src/nvim/eval/executor.c b/src/nvim/eval/executor.c
index 99298cbbcf..e972c506dd 100644
--- a/src/nvim/eval/executor.c
+++ b/src/nvim/eval/executor.c
@@ -16,7 +16,7 @@ static char *e_letwrong = N_("E734: Wrong variable type for %s=");
 
 char *e_listidx = N_("E684: list index out of range: %" PRId64);
 
-/// Hanle tv1 += tv2, -=, .=
+/// Hanle tv1 += tv2, -=, *=, /=,  %=, .=
 ///
 /// @param[in,out]  tv1  First operand, modified typval.
 /// @param[in]  tv2  Second operand.
@@ -51,25 +51,31 @@ int eexe_mod_op(typval_T *const tv1, const typval_T *const tv2,
         if (tv2->v_type == VAR_LIST) {
           break;
         }
-        if (*op == '+' || *op == '-') {
-          // nr += nr  or  nr -= nr
+        if (vim_strchr((char_u *)"+-*/%", *op) != NULL) {
+          // nr += nr  or  nr -= nr, nr *= nr, nr /= nr, nr %= nr
           varnumber_T n = tv_get_number(tv1);
           if (tv2->v_type == VAR_FLOAT) {
             float_T f = (float_T)n;
 
-            if (*op == '+') {
-              f += tv2->vval.v_float;
-            } else {
-              f -= tv2->vval.v_float;
+            if (*op == '%') {
+              break;
+            }
+            switch (*op) {
+              case '+': f += tv2->vval.v_float; break;
+              case '-': f -= tv2->vval.v_float; break;
+              case '*': f *= tv2->vval.v_float; break;
+              case '/': f /= tv2->vval.v_float; break;
             }
             tv_clear(tv1);
             tv1->v_type = VAR_FLOAT;
             tv1->vval.v_float = f;
           } else {
-            if (*op == '+') {
-              n += tv_get_number(tv2);
-            } else {
-              n -= tv_get_number(tv2);
+            switch (*op) {
+              case '+': n += tv_get_number(tv2); break;
+              case '-': n -= tv_get_number(tv2); break;
+              case '*': n *= tv_get_number(tv2); break;
+              case '/': n /= tv_get_number(tv2); break;
+              case '%': n %= tv_get_number(tv2); break;
             }
             tv_clear(tv1);
             tv1->v_type = VAR_NUMBER;
@@ -92,18 +98,20 @@ int eexe_mod_op(typval_T *const tv1, const typval_T *const tv2,
         return OK;
       }
       case VAR_FLOAT: {
-        if (*op == '.' || (tv2->v_type != VAR_FLOAT
-                           && tv2->v_type != VAR_NUMBER
-                           && tv2->v_type != VAR_STRING)) {
+        if (*op == '%' || *op == '.'
+            || (tv2->v_type != VAR_FLOAT
+                && tv2->v_type != VAR_NUMBER
+                && tv2->v_type != VAR_STRING)) {
           break;
         }
         const float_T f = (tv2->v_type == VAR_FLOAT
                            ? tv2->vval.v_float
                            : (float_T)tv_get_number(tv2));
-        if (*op == '+') {
-          tv1->vval.v_float += f;
-        } else {
-          tv1->vval.v_float -= f;
+        switch (*op) {
+          case '+': tv1->vval.v_float += f; break;
+          case '-': tv1->vval.v_float -= f; break;
+          case '*': tv1->vval.v_float *= f; break;
+          case '/': tv1->vval.v_float /= f; break;
         }
         return OK;
       }
diff --git a/src/nvim/testdir/test_vimscript.vim b/src/nvim/testdir/test_vimscript.vim
index 5b16f6d205..05abf04d65 100644
--- a/src/nvim/testdir/test_vimscript.vim
+++ b/src/nvim/testdir/test_vimscript.vim
@@ -1294,6 +1294,84 @@ func Test_script_local_func()
   enew! | close
 endfunc
 
+func Test_compound_assignment_operators()
+    " Test for number
+    let x = 1
+    let x += 10
+    call assert_equal(11, x)
+    let x -= 5
+    call assert_equal(6, x)
+    let x *= 4
+    call assert_equal(24, x)
+    let x /= 3
+    call assert_equal(8, x)
+    let x %= 3
+    call assert_equal(2, x)
+    let x .= 'n'
+    call assert_equal('2n', x)
+
+    " Test for string
+    let x = 'str'
+    let x .= 'ing'
+    call assert_equal('string', x)
+    let x += 1
+    call assert_equal(1, x)
+    let x -= 1.5
+    call assert_equal(-0.5, x)
+
+    if has('float')
+        " Test for float
+        let x = 0.5
+        let x += 4.5
+        call assert_equal(5.0, x)
+        let x -= 1.5
+        call assert_equal(3.5, x)
+        let x *= 3.0
+        call assert_equal(10.5, x)
+        let x /= 2.5
+        call assert_equal(4.2, x)
+        call assert_fails('let x %= 0.5', 'E734')
+        call assert_fails('let x .= "f"', 'E734')
+    endif
+
+    " Test for environment variable
+    let $FOO = 1
+    call assert_fails('let $FOO += 1', 'E734')
+    call assert_fails('let $FOO -= 1', 'E734')
+    call assert_fails('let $FOO *= 1', 'E734')
+    call assert_fails('let $FOO /= 1', 'E734')
+    call assert_fails('let $FOO %= 1', 'E734')
+    let $FOO .= 's'
+    call assert_equal('1s', $FOO)
+    unlet $FOO
+
+    " Test for option variable (type: number)
+    let &scrolljump = 1
+    let &scrolljump += 5
+    call assert_equal(6, &scrolljump)
+    let &scrolljump -= 2
+    call assert_equal(4, &scrolljump)
+    let &scrolljump *= 3
+    call assert_equal(12, &scrolljump)
+    let &scrolljump /= 2
+    call assert_equal(6, &scrolljump)
+    let &scrolljump %= 5
+    call assert_equal(1, &scrolljump)
+    call assert_fails('let &scrolljump .= "j"', 'E734')
+    set scrolljump&vim
+
+    " Test for register
+    let @/ = 1
+    call assert_fails('let @/ += 1', 'E734')
+    call assert_fails('let @/ -= 1', 'E734')
+    call assert_fails('let @/ *= 1', 'E734')
+    call assert_fails('let @/ /= 1', 'E734')
+    call assert_fails('let @/ %= 1', 'E734')
+    let @/ .= 's'
+    call assert_equal('1s', @/)
+    let @/ = ''
+endfunc
+
 "-------------------------------------------------------------------------------
 " Modelines								    {{{1
 " vim: ts=8 sw=4 tw=80 fdm=marker