vim-patch:7.4.1407

Problem:    json_encode() does not handle NaN and inf properly. (David
            Barnett)
Solution:   For JSON turn them into "null".  For JS use "NaN" and "Infinity".
            Add isnan().
f1b6ac7229

src/nvim/eval.c

@@ -47,6 +47,7 @@
 #include "nvim/indent_c.h"
 #include "nvim/indent.h"
 #include "nvim/mark.h"
+#include "nvim/math.h"
 #include "nvim/mbyte.h"
 #include "nvim/memline.h"
 #include "nvim/memory.h"
@@ -12028,6 +12029,12 @@ static void f_islocked(typval_T *argvars, typval_T *rettv, FunPtr fptr)
   clear_lval(&lv);
 }
 
+// "isnan()" function
+static void f_isnan(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+{
+  rettv->vval.v_number = argvars[0].v_type == VAR_FLOAT
+    && xisnan(argvars[0].vval.v_float);
+}
 
 /// Turn a dictionary into a list
 ///

src/nvim/eval.lua

@@ -190,6 +190,7 @@ return {
     invert={args=1},
     isdirectory={args=1},
     islocked={args=1},
+    isnan={args=1},
     id={args=1},
     items={args=1},
     jobclose={args={1, 2}, func="f_chanclose"},

src/nvim/testdir/test_float_func.vim

@@ -289,7 +289,6 @@ func Test_trunc()
 endfunc
 
 func Test_isnan()
-  throw 'skipped: Nvim does not support isnan()'
   call assert_equal(0, isnan(1.0))
   call assert_equal(1, isnan(0.0/0.0))
   call assert_equal(0, isnan(1.0/0.0))