diff --git a/.gitignore b/.gitignore
index 65ece6ae..25ba6526 100644
--- a/.gitignore
+++ b/.gitignore
@@ -10,6 +10,7 @@ janet
 /Emscripten
 /src/include/generated/*.h
 janet-*.tar.gz
+dist
 
 # Emscripten
 *.bc
diff --git a/Makefile b/Makefile
index 29a45d83..d50ddc9e 100644
--- a/Makefile
+++ b/Makefile
@@ -157,7 +157,7 @@ dist: build/janet-dist.tar.gz
 
 build/janet-%.tar.gz: $(JANET_TARGET) src/include/janet/janet.h \
 	janet.1 LICENSE CONTRIBUTING.md $(JANET_LIBRARY) \
-	build/doc.html README.md $(wildcard doc/*)
+	build/doc.html README.md $(wildcard doc/*.md)
 	tar -czvf $@ $^
 
 #########################
diff --git a/appveyor.yml b/appveyor.yml
index c8243a46..c9055a52 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -20,7 +20,10 @@ init:
 install:
     - build_win
     - build_win test
+    - choco install nsis -y -pre
+    - call "C:\Program Files (x86)\NSIS\makensis.exe" janet-installer.nsi 
     - build_win dist
+    - copy janet-install.exe dist\install.exe 
     
 build: off
 
diff --git a/build_win.bat b/build_win.bat
index a5f6483f..1169d393 100644
--- a/build_win.bat
+++ b/build_win.bat
@@ -100,7 +100,6 @@ copy README.md dist\README.md
 copy janet.lib dist\janet.lib
 copy janet.exp dist\janet.exp
 copy src\include\janet\janet.h dist\janet.h
-xcopy /s doc dist\doc
 exit /b 0
 
 :TESTFAIL
diff --git a/janet-installer.nsi b/janet-installer.nsi
new file mode 100644
index 00000000..94a8e2f7
--- /dev/null
+++ b/janet-installer.nsi
@@ -0,0 +1,55 @@
+!define MULTIUSER_EXECUTIONLEVEL Highest
+!define MULTIUSER_MUI
+!define MULTIUSER_INSTALLMODE_COMMANDLINE
+!define MULTIUSER_INSTALLMODE_INSTDIR "janet"
+!include "MultiUser.nsh"
+!include "MUI2.nsh"
+ 
+Name "Janet"
+OutFile "janet-install.exe"
+ 
+!define MUI_ABORTWARNING
+ 
+!insertmacro MUI_PAGE_WELCOME
+!insertmacro MUI_PAGE_LICENSE "LICENSE"
+!insertmacro MUI_PAGE_COMPONENTS
+!insertmacro MULTIUSER_PAGE_INSTALLMODE
+!insertmacro MUI_PAGE_DIRECTORY
+
+!insertmacro MUI_PAGE_INSTFILES
+
+!insertmacro MUI_PAGE_FINISH
+
+!insertmacro MUI_UNPAGE_CONFIRM
+!insertmacro MUI_UNPAGE_INSTFILES
+ 
+!insertmacro MUI_LANGUAGE "English"
+ 
+Section "Janet" BfWSection
+  SetOutPath $INSTDIR
+  File "janet.exe"
+  WriteUninstaller "$INSTDIR\janet-uninstall.exe"
+  
+  # Start Menu
+  CreateShortCut "$SMPROGRAMS\Janet.lnk" "$INSTDIR\janet.exe" "" ""
+SectionEnd
+
+Function .onInit
+  !insertmacro MULTIUSER_INIT
+  !insertmacro MUI_LANGDLL_DISPLAY
+FunctionEnd
+
+!insertmacro MUI_FUNCTION_DESCRIPTION_BEGIN
+  !insertmacro MUI_DESCRIPTION_TEXT ${BfWSection} "The Janet programming language."
+!insertmacro MUI_FUNCTION_DESCRIPTION_END
+ 
+Section "Uninstall"
+  Delete "$INSTDIR\janet.exe"
+  Delete "$INSTDIR\janet-uninstall.exe"
+  RMDir "$INSTDIR"
+SectionEnd
+ 
+Function un.onInit
+  !insertmacro MULTIUSER_UNINIT
+  !insertmacro MUI_UNGETLANGUAGE
+FunctionEnd
\ No newline at end of file
diff --git a/src/include/janet/janet.h b/src/include/janet/janet.h
index f3a6cddd..5e5e74df 100644
--- a/src/include/janet/janet.h
+++ b/src/include/janet/janet.h
@@ -1158,8 +1158,8 @@ JANET_API int janet_typeabstract_err(JanetArgs args, int32_t n, const JanetAbstr
 } while (0)
 #define JANET_CHECKMANY(A, N, TS) do {\
     if ((A).n > (N)) {\
-        JanetType t = janet_type((A).v[(N)]);\
-        if (!((1 << t) & (TS))) return janet_typemany_err(A, N, TS);\
+        JanetType _t_ = janet_type((A).v[(N)]);\
+        if (!((1 << _t_) & (TS))) return janet_typemany_err(A, N, TS);\
     } else {\
        if (!((TS) & JANET_NIL)) return janet_typemany_err(A, N, TS);\
     }\
@@ -1167,9 +1167,9 @@ JANET_API int janet_typeabstract_err(JanetArgs args, int32_t n, const JanetAbstr
 
 #define JANET_CHECKABSTRACT(A, N, AT) do {\
     if ((A).n > (N)) {\
-        Janet x = (A).v[(N)];\
-        if (!janet_checktype(x, JANET_ABSTRACT) ||\
-                janet_abstract_type(janet_unwrap_abstract(x)) != (AT))\
+        Janet _x_ = (A).v[(N)];\
+        if (!janet_checktype(_x_, JANET_ABSTRACT) ||\
+                janet_abstract_type(janet_unwrap_abstract(_x_)) != (AT))\
             return janet_typeabstract_err(A, N, AT);\
     } else {\
         return janet_typeabstract_err(A, N, AT);\
@@ -1177,15 +1177,16 @@ JANET_API int janet_typeabstract_err(JanetArgs args, int32_t n, const JanetAbstr
 } while (0)
 
 #define JANET_ARG_NUMBER(DEST, A, N) do { \
-    if ((A).n <= (N)) \
-        return janet_typemany_err(A, N, JANET_TFLAG_NUMBER);\
-    Janet val = (A).v[(N)];\
-    if (janet_checktype(val, JANET_REAL)) { \
-        DEST = janet_unwrap_real(val); \
-    } else if (janet_checktype(val, JANET_INTEGER)) {\
-        DEST = (double) janet_unwrap_integer(val);\
-    }\
-    else return janet_typemany_err(A, N, JANET_TFLAG_NUMBER); \
+    if ((A).n <= (N)) return janet_typemany_err(A, N, JANET_TFLAG_NUMBER); \
+    Janet _val_ = (A).v[(N)];\
+    JanetType _type_ = janet_type(_val_); \
+    if (_type_ == JANET_REAL) { \
+        DEST = janet_unwrap_real(_val_); \
+    } else if (_type_ == JANET_INTEGER) {\
+        DEST = (double) janet_unwrap_integer(_val_);\
+    } else { \
+        return janet_typemany_err(A, N, JANET_TFLAG_NUMBER); \
+    } \
 } while (0)
 
 #define JANET_ARG_BOOLEAN(DEST, A, N) do { \