Merge pull request #16553 from seandewar/vim-8.2.0878

vim-patch:8.2.{0882,1051,1083}: port `reduce()` function

1 files changed, 97 insertions, 0 deletions

diff --git a/src/nvim/eval/funcs.c b/src/nvim/eval/funcs.c
index 111fae0928..db4fb06a73 100644
--- a/src/nvim/eval/funcs.c
+++ b/src/nvim/eval/funcs.c
@@ -100,6 +100,7 @@ PRAGMA_DIAG_POP
 
 static char *e_listblobarg = N_("E899: Argument of %s must be a List or Blob");
 static char *e_invalwindow = N_("E957: Invalid window number");
+static char *e_reduceempty = N_("E998: Reduce of an empty %s with no initial value");
 
 /// Dummy va_list for passing to vim_snprintf
 ///
@@ -8054,6 +8055,102 @@ static void f_reverse(typval_T *argvars, typval_T *rettv, FunPtr fptr)
   }
 }
 
+/// "reduce(list, { accumlator, element -> value } [, initial])" function
+static void f_reduce(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+{
+  if (argvars[0].v_type != VAR_LIST && argvars[0].v_type != VAR_BLOB) {
+    emsg(_(e_listblobreq));
+    return;
+  }
+
+  const char_u *func_name;
+  partial_T *partial = NULL;
+  if (argvars[1].v_type == VAR_FUNC) {
+    func_name = argvars[1].vval.v_string;
+  } else if (argvars[1].v_type == VAR_PARTIAL) {
+    partial = argvars[1].vval.v_partial;
+    func_name = partial_name(partial);
+  } else {
+    func_name = (const char_u *)tv_get_string(&argvars[1]);
+  }
+  if (*func_name == NUL) {
+    return;  // type error or empty name
+  }
+
+  funcexe_T funcexe = FUNCEXE_INIT;
+  funcexe.evaluate = true;
+  funcexe.partial = partial;
+
+  typval_T initial;
+  typval_T argv[3];
+  if (argvars[0].v_type == VAR_LIST) {
+    list_T *const l = argvars[0].vval.v_list;
+    const listitem_T *li;
+
+    if (argvars[2].v_type == VAR_UNKNOWN) {
+      if (tv_list_len(l) == 0) {
+        semsg(_(e_reduceempty), "List");
+        return;
+      }
+      const listitem_T *const first = tv_list_first(l);
+      initial = *TV_LIST_ITEM_TV(first);
+      li = TV_LIST_ITEM_NEXT(l, first);
+    } else {
+      initial = argvars[2];
+      li = tv_list_first(l);
+    }
+
+    tv_copy(&initial, rettv);
+
+    if (l != NULL) {
+      const VarLockStatus prev_locked = tv_list_locked(l);
+      const int called_emsg_start = called_emsg;
+
+      tv_list_set_lock(l, VAR_FIXED);  // disallow the list changing here
+      for (; li != NULL; li = TV_LIST_ITEM_NEXT(l, li)) {
+        argv[0] = *rettv;
+        argv[1] = *TV_LIST_ITEM_TV(li);
+        rettv->v_type = VAR_UNKNOWN;
+        const int r = call_func(func_name, -1, rettv, 2, argv, &funcexe);
+        tv_clear(&argv[0]);
+        if (r == FAIL || called_emsg != called_emsg_start) {
+          break;
+        }
+      }
+      tv_list_set_lock(l, prev_locked);
+    }
+  } else {
+    const blob_T *const b = argvars[0].vval.v_blob;
+    int i;
+
+    if (argvars[2].v_type == VAR_UNKNOWN) {
+      if (tv_blob_len(b) == 0) {
+        semsg(_(e_reduceempty), "Blob");
+        return;
+      }
+      initial.v_type = VAR_NUMBER;
+      initial.vval.v_number = tv_blob_get(b, 0);
+      i = 1;
+    } else if (argvars[2].v_type != VAR_NUMBER) {
+      emsg(_(e_number_exp));
+      return;
+    } else {
+      initial = argvars[2];
+      i = 0;
+    }
+
+    tv_copy(&initial, rettv);
+    for (; i < tv_blob_len(b); i++) {
+      argv[0] = *rettv;
+      argv[1].v_type = VAR_NUMBER;
+      argv[1].vval.v_number = tv_blob_get(b, i);
+      if (call_func(func_name, -1, rettv, 2, argv, &funcexe) == FAIL) {
+        return;
+      }
+    }
+  }
+}
+
 #define SP_NOMOVE       0x01        ///< don't move cursor
 #define SP_REPEAT       0x02        ///< repeat to find outer pair
 #define SP_RETCOUNT     0x04        ///< return matchcount