diff --git a/client/main.c b/client/main.c
index f64cda0d..011c9080 100644
--- a/client/main.c
+++ b/client/main.c
@@ -45,8 +45,8 @@ int debug_compile_and_run(Gst *vm, GstValue ast, GstValue last) {
     gst_compiler_globals(&c, gst_wrap_table(vm->registry));
     func = gst_wrap_function(gst_compiler_compile(&c, ast));
     /* Check for compilation errors */
-    if (c.error) {
-        printf("Compiler error: %s\n", c.error);
+    if (c.error.type != GST_NIL) {
+        printf("Compiler error: %s\n", (const char *)gst_to_string(vm, c.error));
         return 1;
     }
     /* Execute function */
@@ -54,7 +54,7 @@ int debug_compile_and_run(Gst *vm, GstValue ast, GstValue last) {
         if (vm->crash) {
             printf("VM crash: %s\n", vm->crash);
         } else {
-            printf("VM error: %s\n", (char *)gst_to_string(vm, vm->ret));
+            printf("VM error: %s\n", (const char *)gst_to_string(vm, vm->ret));
         }
         return 1;
     }
@@ -63,35 +63,43 @@ int debug_compile_and_run(Gst *vm, GstValue ast, GstValue last) {
 
 /* Parse a file and execute it */
 int debug_run(Gst *vm, FILE *in) {
-    char buffer[1024] = {0};
+    char buffer[2048] = {0};
     const char *reader = buffer;
-    GstValue ast;
     GstParser p;
-    /* Init parser */
-    gst_parser(&p, vm);
-    /* Get and parse input until we have a full form */
-    while (p.status != GST_PARSER_ERROR) {
-        if (*reader == '\0') {
-            if (!fgets(buffer, sizeof(buffer), in)) {
-                /* Check that parser is complete */
-                if (p.status != GST_PARSER_FULL && p.status != GST_PARSER_ROOT) {
-                    printf("Unexpected end of source\n");
-                    return 1;
+    for (;;) {
+        /* Init parser */
+        gst_parser(&p, vm);
+        while (p.status != GST_PARSER_ERROR && p.status != GST_PARSER_FULL) {
+            if (*reader == '\0') {
+                if (!fgets(buffer, sizeof(buffer), in)) {
+                    /* Add possible end of line */
+                    if (p.status == GST_PARSER_PENDING) 
+                        gst_parse_cstring(&p, "\n");
+                    /* Check that parser is complete */
+                    if (p.status != GST_PARSER_FULL && p.status != GST_PARSER_ROOT) {
+                        printf("Unexpected end of source\n");
+                        return 1;
+                    }
+                    /* Otherwise we finished the file with no problems*/
+                    return 0;
                 }
-                return 0;
+                reader = buffer;
             }
-            reader = buffer;
-        }
-        if (p.status != GST_PARSER_FULL)
             reader += gst_parse_cstring(&p, reader);
-        if (gst_parse_hasvalue(&p)) {
-            ast = gst_parse_consume(&p);
-            debug_compile_and_run(vm, ast, gst_wrap_nil());
         }
-    }
-    /* Check if file read in correctly */
-    if (p.error) {
-        printf("Parse error: %s\n", p.error);
+        /* Check if file read in correctly */
+        if (p.error) {
+            printf("Parse error: %s\n", p.error);
+            break;
+        }
+        /* Check that parser is complete */
+        if (p.status != GST_PARSER_FULL && p.status != GST_PARSER_ROOT) {
+            printf("Unexpected end of source\n");
+            break;
+        }
+        if (debug_compile_and_run(vm, gst_parse_consume(&p), vm->ret)) {
+            break;
+        }
     }
     return 1;
 }
diff --git a/core/compile.c b/core/compile.c
index 10354a6d..e2051a04 100644
--- a/core/compile.c
+++ b/core/compile.c
@@ -117,6 +117,11 @@ BUFFER_DEFINE(i16, int16_t)
 /* If there is an error during compilation,
  * jump back to start */
 static void c_error(GstCompiler *c, const char *e) {
+    c->error = gst_string_cv(c->vm, e);
+    longjmp(c->onError, 1);
+}
+
+static void c_error1(GstCompiler *c, GstValue e) {
     c->error = e;
     longjmp(c->onError, 1);
 }
@@ -183,7 +188,11 @@ static uint16_t compiler_get_local(GstCompiler *c, GstScope *scope) {
         if (scope->nextLocal + 1 == 0) {
             c_error(c, "too many local variables");
         }
-        return scope->nextLocal++;
+        ++scope->nextLocal;
+        if (scope->nextLocal > scope->frameSize) {
+            scope->frameSize = scope->nextLocal;
+        }
+        return scope->nextLocal - 1;
     } else {
         return scope->freeHeap[--scope->heapSize];
     }
@@ -471,7 +480,7 @@ static Slot compile_symbol(GstCompiler *c, FormOptions opts, GstValue sym) {
     Slot ret;
     int status = symbol_resolve(c, sym, &level, &index, &lit);
     if (!status) {
-        c_error(c, "undefined symbol");
+        c_error1(c, sym);
     }
     if (opts.resultUnused) return nil_slot();
     if (status == 2) {
@@ -626,7 +635,7 @@ static Slot compile_function(GstCompiler *c, FormOptions opts, const GstValue *f
     GstArray *params;
     FormOptions subOpts = form_options_default();
     Slot ret;
-    int varargs;
+    int varargs = 0;
     uint32_t arity;
     if (opts.resultUnused) return nil_slot();
     ret = compiler_get_target(c, opts);
@@ -1092,7 +1101,7 @@ void gst_compiler(GstCompiler *c, Gst *vm) {
     c->vm = vm;
     c->buffer = gst_buffer(vm, 128);
     c->tail = NULL;
-    c->error = NULL;
+    c->error.type = GST_NIL;
     c->trackers = NULL;
     compiler_push_scope(c, 0);
 }
@@ -1135,8 +1144,8 @@ GstFunction *gst_compiler_compile(GstCompiler *c, GstValue form) {
         c->trackers = NULL;
         if (c->tail)
             c->tail->parent = NULL;
-        if (c->error == NULL)
-            c->error = "unknown error";
+        if (c->error.type == GST_NIL)
+            c->error = gst_string_cv(c->vm, "unknown error");
         return NULL;
     }
     /* Create a scope */
@@ -1169,6 +1178,7 @@ static void gst_compiler_mark(Gst *vm, void *data, uint32_t len) {
     	return;
     /* Mark compiler */
     gst_mark_value(vm, gst_wrap_buffer(c->buffer));
+    gst_mark_value(vm, c->error);
     /* Mark trackers - the trackers themselves are all on the stack. */
     st = (SlotTracker *) c->trackers;
     while (st) {
@@ -1232,7 +1242,7 @@ static int gst_stl_compiler_compile(Gst *vm) {
     	gst_c_throwc(vm, "expected compiler");
     ret = gst_compiler_compile(c, gst_arg(vm, 1));
     if (ret == NULL)
-        gst_c_throwc(vm, c->error);
+        gst_c_throw(vm, c->error);
     gst_c_return(vm, gst_wrap_function(ret));
 }
 
diff --git a/core/parse.c b/core/parse.c
index 4544bd30..3611c80e 100644
--- a/core/parse.c
+++ b/core/parse.c
@@ -153,7 +153,7 @@ static int is_symbol_char(uint8_t c) {
     if (c >= '0' && c <= ':') return 1;
     if (c >= '<' && c <= '@') return 1;
     if (c >= '*' && c <= '/') return 1;
-    if (c >= '$' && c == '&') return 1;
+    if (c >= '#' && c <= '&') return 1;
     if (c == '_') return 1;
     if (c == '^') return 1;
     if (c == '!') return 1;
@@ -444,22 +444,6 @@ static int form_state(GstParser *p, uint8_t c) {
 static void dispatch_char(GstParser *p, uint8_t c) {
     int done = 0;
     ++p->index;
-    /* Handle comments */
-    if (p->flags & GST_PARSER_FLAG_INCOMMENT) {
-        if (c == '\n') {
-            p->flags = GST_PARSER_FLAG_EXPECTING_COMMENT;
-        }
-        return;
-    } else if (p->flags & GST_PARSER_FLAG_EXPECTING_COMMENT) {
-        if (c == '#') {
-            p->flags = GST_PARSER_FLAG_INCOMMENT;
-            return;
-        } else if (!is_whitespace(c)) {
-            p->flags = 0;
-        } else {
-            return;
-        }
-    }
     /* Dispatch character to state */
     while (!done) {
         GstParseState *top = parser_peek(p);
@@ -504,6 +488,11 @@ int gst_parse_string(GstParser *p, const uint8_t *string) {
     return i;
 }
 
+/* Parse a single byte */
+void gst_parse_byte(GstParser *p, uint8_t byte) {
+    dispatch_char(p, byte);
+}
+
 /* Check if a parser has a value that needs to be handled. If
  * so, the parser will not parse any more input until that value
  * is consumed. */
@@ -529,7 +518,6 @@ void gst_parser(GstParser *p, Gst *vm) {
     p->error = NULL;
     p->status = GST_PARSER_ROOT;
     p->value.type = GST_NIL;
-    p->flags = GST_PARSER_FLAG_EXPECTING_COMMENT;
     parser_push(p, PTYPE_ROOT, ' ');
 }
 
diff --git a/core/thread.c b/core/thread.c
index 9cc4422f..3659dd23 100644
--- a/core/thread.c
+++ b/core/thread.c
@@ -85,11 +85,13 @@ void gst_thread_pushnil(Gst *vm, GstThread *thread, uint32_t n) {
 void gst_thread_tuplepack(Gst *vm, GstThread *thread, uint32_t n) {
     GstValue *stack = thread->data + thread->count;
     uint32_t size = gst_frame_size(stack);
-    if (n >= size) {
+    if (n > size) {
+        /* Push one extra nil to ensure space for tuple */
         gst_thread_pushnil(vm, thread, n - size + 1);
         stack = thread->data + thread->count;
         stack[n].type = GST_TUPLE;
         stack[n].data.tuple = gst_tuple_end(vm, gst_tuple_begin(vm, 0));
+        gst_frame_size(stack) = n + 1;
     } else {
         uint32_t i;
         GstValue *tuple = gst_tuple_begin(vm, size - n);
@@ -97,7 +99,6 @@ void gst_thread_tuplepack(Gst *vm, GstThread *thread, uint32_t n) {
             tuple[i - n] = stack[i];
         stack[n].type = GST_TUPLE;
         stack[n].data.tuple = gst_tuple_end(vm, tuple);
-        gst_frame_size(stack) = n + 1;
     }
 }
 
diff --git a/core/vm.c b/core/vm.c
index 1432c4f8..b263272f 100644
--- a/core/vm.c
+++ b/core/vm.c
@@ -242,6 +242,7 @@ int gst_continue(Gst *vm) {
                 stack = gst_thread_stack(vm->thread);
                 for (i = 0; i < count; ++i)
                     stack[oldsize + i] = data[i];
+                /*gst_frame_size(stack) += count;*/
                 pc += 2;
             }
             break;
diff --git a/include/gst/compile.h b/include/gst/compile.h
index 829958ed..a4378773 100644
--- a/include/gst/compile.h
+++ b/include/gst/compile.h
@@ -32,7 +32,7 @@ typedef struct GstScope GstScope;
 /* Compilation state */
 struct GstCompiler {
     Gst *vm;
-    const char *error;
+    GstValue error;
     jmp_buf onError;
     GstScope *tail;
     GstBuffer *buffer;
diff --git a/include/gst/parse.h b/include/gst/parse.h
index 17aa5158..6f8b04ef 100644
--- a/include/gst/parse.h
+++ b/include/gst/parse.h
@@ -37,7 +37,6 @@ struct GstParser {
     uint32_t count;
     uint32_t cap;
     uint32_t index;
-    uint32_t flags;
     uint32_t quoteCount;
     enum {
 		GST_PARSER_PENDING = 0,
@@ -47,10 +46,6 @@ struct GstParser {
     } status;
 };
 
-/* Some parser flags */
-#define GST_PARSER_FLAG_INCOMMENT 1
-#define GST_PARSER_FLAG_EXPECTING_COMMENT 2
-
 /* Initialize a parser */
 void gst_parser(GstParser *p, Gst *vm);
 
@@ -60,6 +55,9 @@ int gst_parse_cstring(GstParser *p, const char *string);
 /* Parse a gst string. Returns number of bytes read */
 int gst_parse_string(GstParser *p, const uint8_t *string);
 
+/* Parse a single byte */
+void gst_parse_byte(GstParser *p, uint8_t byte);
+
 /* Check if a parser has a value that needs to be handled. If
  * so, the parser will not parse any more input until that value
  * is consumed. */
diff --git a/libs/compile.gst b/libs/compile.gst
deleted file mode 100644
index e743757d..00000000
--- a/libs/compile.gst
+++ /dev/null
@@ -1,27 +0,0 @@
-# Real compiler
-
-# Make compiler
-(: make-compiler (fn [] {
-    'scopes []
-    'env []
-    'labels {}
-}))
-
-# Make default form options
-(: make-formopts (fn [] {
-    'target nil
-    'resultUnused false
-    'canChoose true
-    'isTail false
-}))
-
-# Make scope
-(: make-scope (fn [] {
-    'level 0
-    'nextSlot 0
-    'frameSize 0
-    'freeSlots []
-    'literals {}
-    'literalsArray []
-    'slotMap []
-}))
diff --git a/libs/hello.gst b/libs/hello.gst
new file mode 100644
index 00000000..298f057e
--- /dev/null
+++ b/libs/hello.gst
@@ -0,0 +1,13 @@
+(print "Hello, World!")
+
+(do (+ 1 2 3))
+
+(print _ )
+
+"Comment"
+(do
+    (: i 0)
+    (while (< i 1000)
+        (print i)
+        (: i (+ i 1)))
+)
diff --git a/libs/parse.gst b/libs/parse.gst
deleted file mode 100644
index e6e9478c..00000000
--- a/libs/parse.gst
+++ /dev/null
@@ -1,8 +0,0 @@
-# Make parser
-
-(: parser (fn [in] {
-    'in in
-    'line 0
-    'index 0
-    'states []
-}))
diff --git a/libs/pp.gst b/libs/pp.gst
index 734b15e3..8474ce54 100644
--- a/libs/pp.gst
+++ b/libs/pp.gst
@@ -1,9 +1,8 @@
 (do
 
-# Declare pretty print
 (: pp nil)
 
-# Pretty print an array or tuple
+"Pretty print an array or tuple"
 (: print-seq (fn [start end a seen]
     (: seen (if seen seen {}))
     (if (get seen a) (get seen a)
@@ -21,7 +20,7 @@
             (set! seen a ret)
             ret))))
 
-# Pretty print an object or struct
+"Pretty print an object or struct"
 (: print-struct (fn [start end s seen]
     (: seen (if seen seen {}))
     (if (get seen s) (get seen s)
@@ -40,7 +39,7 @@
             (set! seen s ret)
             ret))))
 
-# Type handlers
+"Type handlers"
 (: handlers {
     "array" (fn [a seen] (print-seq "[" "]" a seen))
     "tuple" (fn [a seen] (print-seq "(" ")" a seen))
@@ -48,13 +47,13 @@
     "struct" (fn [s seen] (print-struct "#{" "}" s seen))
  })
 
-# Define pretty print
+"Define pretty print"
 (: pp (fn [x seen]
     (: handler (get handlers (type x)))
     (: handler (if handler handler tostring))
     (handler x seen)))
 
-# Export pretty print
+"Export pretty print"
 (export! 'pp pp)
 
 )
diff --git a/libs/stl.gst b/libs/stl.gst
deleted file mode 100644
index 4180ef7d..00000000
--- a/libs/stl.gst
+++ /dev/null
@@ -1,4 +0,0 @@
-(print 1)
-
-(: counter 0)
-(while (< counter 100) (print counter) (: counter (+ 1 counter)))