diff --git a/powershell/core.psm1 b/powershell/core.psm1
index b2e592de..2c64dcdb 100644
--- a/powershell/core.psm1
+++ b/powershell/core.psm1
@@ -115,8 +115,8 @@ $core_ns = @{
 
     "pr-str"      = { pr_seq $args $true  " " };
     "str"         = { pr_seq $args $false "" };
-    "prn"         = { Write-Host (pr_seq $args $true  " ") };
-    "println"     = { Write-Host (pr_seq $args $false " ") };
+    "prn"         = { Write-Host (pr_seq $args $true  " "); $null };
+    "println"     = { Write-Host (pr_seq $args $false " "); $null };
     "read-string" = { read_str $args[0] };
     "readline"    = { Write-Host $args[0] -NoNewline; [Console]::Readline() };
     "slurp"       = { Get-Content -Path $args[0] -Raw };
diff --git a/r/Makefile b/r/Makefile
index f9ec4a74..1b7e65e2 100644
--- a/r/Makefile
+++ b/r/Makefile
@@ -2,6 +2,10 @@ SOURCES_BASE = readline.r types.r reader.r printer.r
 SOURCES_LISP = env.r core.r stepA_mal.r
 SOURCES = $(SOURCES_BASE) $(SOURCES_LISP)
 
+STEPS = step0_repl.r step1_read_print.r step2_eval.r step3_env.r \
+	step4_if_fn_do.r step5_tco.r step6_file.r \
+	step7_quote.r step8_macros.r step9_try.r stepA_mal.r
+
 all: libs
 
 dist: mal.r mal
@@ -14,8 +18,7 @@ mal: mal.r
 	cat $< >> $@
 	chmod +x $@
 
-clean:
-	rm -f mal.r mal
+$(STEPS): libs
 
 .PHONY:
 libs: lib/rdyncall
@@ -25,3 +28,8 @@ lib/rdyncall:
 	mkdir -p lib
 	R CMD INSTALL rdyncall_0.7.5.tar.gz -l lib/
 	rm rdyncall_0.7.5.tar.gz
+
+clean:
+	rm -f mal.r mal
+
+
diff --git a/rexx/core.rexx b/rexx/core.rexx
index 647317a3..63fe5551 100644
--- a/rexx/core.rexx
+++ b/rexx/core.rexx
@@ -99,7 +99,7 @@ mal_readline: procedure expose values. /* mal_readline(prompt) */
   return new_nil()
 
 mal_slurp: procedure expose values. /* mal_read_string(filename) */
-  file_content = charin(obj_val(arg(1)), , 100000)
+  file_content = charin(obj_val(arg(1)), 1, 100000)
   return new_string(file_content)
 
 mal_lt: procedure expose values. /* mal_lt(a, b) */
diff --git a/tests/step4_if_fn_do.mal b/tests/step4_if_fn_do.mal
index c1721f4f..1f2f69eb 100644
--- a/tests/step4_if_fn_do.mal
+++ b/tests/step4_if_fn_do.mal
@@ -127,6 +127,8 @@
 ;=>false
 (= (list) 0)
 ;=>false
+(= (list nil) (list))
+;=>false
 
 
 ;; Testing builtin and user defined functions
diff --git a/tests/step6_file.mal b/tests/step6_file.mal
index cf1fd2f2..ec503974 100644
--- a/tests/step6_file.mal
+++ b/tests/step6_file.mal
@@ -25,6 +25,10 @@
 (slurp "../tests/test.txt")
 ;=>"A line of text\n"
 
+;;; Load the same file twice.
+(slurp "../tests/test.txt")
+;=>"A line of text\n"
+
 ;; Testing load-file
 
 (load-file "../tests/inc.mal")