diff --git a/SMILEBASIC/SMILEBASIC.visualdproj b/SMILEBASIC/SMILEBASIC.visualdproj
index af0f869..7155be3 100644
--- a/SMILEBASIC/SMILEBASIC.visualdproj
+++ b/SMILEBASIC/SMILEBASIC.visualdproj
@@ -212,6 +212,7 @@
   <File path="node.d" />
   <File path="parser.d" />
   <File path="petitcomputer.d" />
+  <File path="TEST.txt" />
   <File path="token.d" />
   <File path="type.d" />
   <File path="VM.d" />
diff --git a/SMILEBASIC/TEST.txt b/SMILEBASIC/TEST.txt
new file mode 100644
index 0000000..4092d13
--- /dev/null
+++ b/SMILEBASIC/TEST.txt
@@ -0,0 +1,28 @@
+ASSERT__ 1, "TRUE"
+A$="A"
+ASSERT__ A$=="A", "A$==A"
+A$=A$+"B"
+ASSERT__ A$=="AB", "A$==AA"
+A=0
+INC A
+ASSERT__ A==1, "A==1"
+INC A, 3
+ASSERT__ A==4, "A==4"
+DEC A, 3
+ASSERT__ A==1, "A==1"
+DEC A
+ASSERT__ A==0, "A==0"
+INCTEST 0
+DEF INCTEST A
+ INC A
+ ASSERT__ A==1, "A==1"
+ INC A, 3
+ ASSERT__ A==4, "A==4"
+ DEC A, 3
+ ASSERT__ A==1, "A==1"
+ DEC A
+ ASSERT__ A==0, "A==0"
+END
+LOCATE 10,
+COLOR 1,15
+PRINT "テスト正常終了"
\ No newline at end of file
diff --git a/SMILEBASIC/builtinfunctions.d b/SMILEBASIC/builtinfunctions.d
index e0f8479..0ba6147 100644
--- a/SMILEBASIC/builtinfunctions.d
+++ b/SMILEBASIC/builtinfunctions.d
@@ -94,6 +94,14 @@ class BuiltinFunction
     {
         p.cls;
     }
+    static void ASSERT__(PetitComputer p, int cond, wstring message)
+    {
+        if(!cond)
+        {
+            p.printConsole("Assertion failed: ", message, "\n");
+        }
+        assert(cond, message.to!string);
+    }
     //alias void function(PetitComputer, Value[], Value[]) BuiltinFunc;
     static BuiltinFunction[wstring] builtinFunctions;
     static this()
@@ -202,6 +210,10 @@ template GetFunctionParamType(T, string N)
             {
                 const string arg = "ValueType.Integer, false";
             }
+            else static if(is(P[0] == wstring))
+            {
+                const string arg = "ValueType.String, false";
+            }
             else static if(is(P[0] == DefaultValue!int))
             {
                 const string arg = "ValueType.Integer, true";
@@ -250,6 +262,11 @@ template AddFuncArg(int L, int N, int M, P...)
         enum add = 1;
         const string arg = "arg[" ~ I.to!string ~ "].castInteger";
     }
+    else static if(is(P[0] == wstring))
+    {
+        enum add = 1;
+        const string arg = "arg[" ~ I.to!string ~ "].castString";
+    }
     else static if(is(P[0] == DefaultValue!int))
     {
         enum add = 1;
diff --git a/SMILEBASIC/parser.d b/SMILEBASIC/parser.d
index a27245e..032805e 100644
--- a/SMILEBASIC/parser.d
+++ b/SMILEBASIC/parser.d
@@ -537,6 +537,7 @@ class Parser
         }
         isFuncReturnExpr = node.returnExpr;//面倒くさい
         node.functionBody = functionStatements();
+        lex.popFront();
         isFuncReturnExpr = false;
         return node;
     }
diff --git a/SMILEBASIC/petitcomputer.d b/SMILEBASIC/petitcomputer.d
index 637086c..55c049d 100644
--- a/SMILEBASIC/petitcomputer.d
+++ b/SMILEBASIC/petitcomputer.d
@@ -347,7 +347,7 @@ class PetitComputer
             }
         }+/
         //とりあえず
-        auto parser = new Parser(/*readText("FIZZBUZZ.TXT").to!wstring*//*"
+        auto parser = new Parser(readText("TEST.TXT").to!wstring/*readText("FIZZBUZZ.TXT").to!wstring*//*"
 ?ABS(-1)
 LOCATE 0,10
 COLOR 5
@@ -357,10 +357,10 @@ NEXT
 DEF FACT(N)
  IF N<=1 THEN RETURN 1
  RETURN N*FACT(N-1)
-END"*/
+END"*//*
 `CLS : CL=0 : Z=0
 WHILE 1
-INC Z
+INC Z,2
 ?Z,
 WEND
 WHILE 1
@@ -370,7 +370,7 @@ WHILE 1
     PRINT "★ 梅雨で雨が多い季節ですね ★"
   NEXT
   CL=(CL+1) MOD 16 : VSYNC 2
-WEND`/*
+WEND`*//*
 `CLS : CL=0
 WHILE 1
 FOR I=0 TO 15
@@ -452,7 +452,7 @@ GOTO @LOOP`*/
                 auto back = console[y][x].backColor;
                 auto fore = consoleColor[console[y][x].foreColor];
                 auto texture = GRPFColor[back].texture;
-                //SDL_RenderCopy(renderer, texture, &fontTable[console[y][x].charater], &rect);
+                SDL_RenderCopy(renderer, texture, &fontTable[console[y][x].charater], &rect);
                 SDL_SetTextureColorMod(GRPF.texture, fore >> 16 & 0xFF, fore >> 8 & 0xFF, fore & 0xFF);
                 SDL_SetTextureAlphaMod(GRPF.texture, fore >> 24 & 0xFF);
                 SDL_RenderCopy(renderer, GRPF.texture, &fontTable[console[y][x].charater], &rect);
diff --git a/SMILEBASIC/type.d b/SMILEBASIC/type.d
index 380c9bc..466865a 100644
--- a/SMILEBASIC/type.d
+++ b/SMILEBASIC/type.d
@@ -90,6 +90,10 @@ struct Value
     {
         return this.type == ValueType.Integer ? this.integerValue : (this.type == ValueType.Double ? this.doubleValue : 0);
     }
+    wstring castString()
+    {
+        return this.type == ValueType.String ? this.stringValue : "";
+    }
     string toString()
     {
         import std.conv;