[Lang] Fix string format not support keywords format (#3256)

* fix: string format not support keywords format

* fix: format in test

python/taichi/lang/impl.py

@@ -701,20 +701,26 @@ def fused_string(entries):
 
 
 @taichi_scope
-def ti_format(*args):
+def ti_format(*args, **kwargs):
     content = args[0]
     mixed = args[1:]
     new_mixed = []
+    new_mixed_kwargs = {}
     args = []
     for x in mixed:
         if isinstance(x, ti.Expr):
             new_mixed.append('{}')
             args.append(x)
         else:
             new_mixed.append(x)
-
+    for k, v in kwargs.items():
+        if isinstance(v, ti.Expr):
+            new_mixed_kwargs[k] = '{}'
+            args.append(v)
+        else:
+            new_mixed_kwargs[k] = v
     try:
-        content = content.format(*new_mixed)
+        content = content.format(*new_mixed, **new_mixed_kwargs)
     except ValueError:
         print('Number formatting is not supported with Taichi fields')
         exit(1)

tests/python/test_print.py

@@ -126,3 +126,19 @@ def test_python_scope_print_field():
     print(x)
     print(y)
     print(z)
+
+
+@ti.test(arch=ti.cpu)
+def test_print_string_format():
+    @ti.kernel
+    def func(k: ti.f32):
+        print(123)
+        print("{} abc".format(123))
+        print("{} {} {}".format(1, 2, 3))
+        print("{} {name} {value}".format(k, name=999, value=123))
+        name = 123.4
+        value = 456.7
+        print("{} {name} {value}".format(k, name=name, value=value))
+
+    func(233.3)
+    ti.sync()