diff --git a/documentation/plthy.pdf b/documentation/plthy.pdf
index 18f97b3..e1b4856 100644
Binary files a/documentation/plthy.pdf and b/documentation/plthy.pdf differ
diff --git a/documentation/plthy.tex b/documentation/plthy.tex
index 7ddf0cc..556dfcb 100644
--- a/documentation/plthy.tex
+++ b/documentation/plthy.tex
@@ -37,7 +37,9 @@
         \textit{expression} & $\rightarrow$ & \textit{expression} \texttt{\{} \textit{expression} \texttt{\}} \\ \hline
         \textit{expression} & $\rightarrow$ & \texttt{(} \textit{expression} \texttt{)} \\ \hline
         \textit{expression} & $\rightarrow$ & \textit{expression} \textbf{binop} \textit{expression} \\ \hline
+        \textit{expression} & $\rightarrow$ & \textbf{unop} \textit{expression} \\ \hline
         \textit{expression} & $\rightarrow$ & \texttt{variable} \textbf{id}\\ \hline
+        \textit{expression} & $\rightarrow$ & \texttt{argument} \textbf{arg} \\ \hline
         \textit{expression} & $\rightarrow$ & \textit{statement} \\ \hline
     \end{tabular}
     \end{center}
diff --git a/plthy b/plthy
index aeb860a..559430f 100755
--- a/plthy
+++ b/plthy
@@ -1,4 +1,4 @@
-#! /home/nikolaj/.pyenv/shims/python
+#!/usr/bin/env python
 """
 Usage:
     plthy (-h| --help)
diff --git a/plthy_impl/parser.py b/plthy_impl/parser.py
index 2d4f7d5..14826ae 100644
--- a/plthy_impl/parser.py
+++ b/plthy_impl/parser.py
@@ -37,17 +37,21 @@ class Parser():
         def statement_skip(tokens):
             return ast_nodes.StatementSkip()
 
-        @self.pg.production('statement : KEYWORD_SET expression SYMBOL_SET ID')
-        def statement_set(tokens):
-            return ast_nodes.StatementSet(tokens[1], tokens[3].value)
+        @self.pg.production('statement : KEYWORD_MAYBE statement')
+        def statement_maybe(tokens):
+            return ast_nodes.Maybe(tokens[1])
 
         @self.pg.production('statement : KEYWORD_DO command')
         def statement_do(tokens):
             return ast_nodes.Do(tokens[1])
 
-        @self.pg.production('statement : KEYWORD_MAYBE statement')
-        def statement_maybe(tokens):
-            return ast_nodes.Maybe(tokens[1])
+        @self.pg.production('statement : SYMBOL_LBRACKET statements SYMBOL_RBRACKET')
+        def statement_scope(tokens):
+            return ast_nodes.Scope(tokens[1])
+
+        @self.pg.production('statement : KEYWORD_SET expression SYMBOL_SET ID')
+        def statement_set(tokens):
+            return ast_nodes.StatementSet(tokens[1], tokens[3].value)
 
         @self.pg.production('statement : KEYWORD_DEFINE ID SYMBOL_LT DATA_INT SYMBOL_GT KEYWORD_AS statement', precedence="KEYWORD_DEFINE")
         def statement_define(tokens):
@@ -57,19 +61,7 @@ class Parser():
         def statement_return(tokens):
             return ast_nodes.StatementReturn(tokens[1])
 
-        @self.pg.production('statement : SYMBOL_LBRACKET statements SYMBOL_RBRACKET')
-        def statement_scope(tokens):
-            return ast_nodes.Scope(tokens[1])
-
         ## command ##
-        @self.pg.production('command : BUILTIN SYMBOL_LT expressions SYMBOL_GT')
-        def command_builtin(tokens):
-            return ast_nodes.Builtin(tokens[0], tokens[2])
-
-        @self.pg.production('command : SYMBOL_QUOTE ID SYMBOL_QUOTE SYMBOL_LT expressions SYMBOL_GT')
-        def command_call(tokens):
-            return ast_nodes.Call(tokens[1].value,tokens[4])
-
         @self.pg.production('command : statement KEYWORD_IF expression')
         def command_if(tokens):
             return ast_nodes.CommandIf(tokens[0], tokens[2])
@@ -86,6 +78,14 @@ class Parser():
         def command_until(tokens):
             return ast_nodes.CommandUntil(tokens[0],tokens[2])
 
+        @self.pg.production('command : BUILTIN SYMBOL_LT expressions SYMBOL_GT')
+        def command_builtin(tokens):
+            return ast_nodes.Builtin(tokens[0], tokens[2])
+
+        @self.pg.production('command : SYMBOL_QUOTE ID SYMBOL_QUOTE SYMBOL_LT expressions SYMBOL_GT')
+        def command_call(tokens):
+            return ast_nodes.Call(tokens[1].value,tokens[4])
+
         ## expressions ##
         @self.pg.production('expressions : ')
         def expressions_none(_):
@@ -96,29 +96,31 @@ class Parser():
             return [tokens[0]] + tokens[2]
 
         ## expression ##
+        @self.pg.production('expression : DATA_STRING')
+        def exp_string(tokens):
+            return ast_nodes.ExpString(tokens[0].value[1:-1])
+
         @self.pg.production('expression : DATA_INT')
         def exp_int(tokens):
             return ast_nodes.ExpInt(int(tokens[0].value))
 
-        @self.pg.production('expression : SYMBOL_LPARENS expression SYMBOL_RPARENS')
-        def exp_paren(tokens):
-            return tokens[1]
-
         @self.pg.production('expression : DATA_FLOAT')
         def exp_float(tokens):
             return ast_nodes.ExpInt(float(tokens[0].value))
 
-        @self.pg.production('expression : DATA_STRING')
-        def exp_string(tokens):
-            return ast_nodes.ExpString(tokens[0].value[1:-1])
+        # Boolean
 
-        @self.pg.production('expression : statement', precedence="KEYWORD_IF")
-        def exp_statement(tokens):
-            return(tokens[0])
+        @self.pg.production('expression : SYMBOL_LCURL expressions SYMBOL_RCURL')
+        def exp_list(tokens):
+            return ast_nodes.ExpList(tokens[1])
 
-        @self.pg.production('expression : KEYWORD_VARIABLE ID')
-        def exp_variable(tokens):
-            return ast_nodes.ExpVariable(tokens[1].value)
+        @self.pg.production('expression : expression SYMBOL_LCURL expression SYMBOL_RCURL')
+        def exp_index(tokens):
+            return ast_nodes.ExpIndex(tokens[0],tokens[2])
+
+        @self.pg.production('expression : SYMBOL_LPARENS expression SYMBOL_RPARENS')
+        def exp_paren(tokens):
+            return tokens[1]
 
         @self.pg.production('expression : expression SYMBOL_PLUS expression')
         @self.pg.production('expression : expression SYMBOL_MINUS expression')
@@ -139,17 +141,17 @@ class Parser():
         def exp_not(tokens):
             pass
 
+        @self.pg.production('expression : KEYWORD_VARIABLE ID')
+        def exp_variable(tokens):
+            return ast_nodes.ExpVariable(tokens[1].value)
+
         @self.pg.production('expression : KEYWORD_ARGUMENT ARG')
         def exp_arg(tokens):
             return ast_nodes.ExpArg(int(tokens[1].value[1:]))
 
-        @self.pg.production('expression : SYMBOL_LCURL expressions SYMBOL_RCURL')
-        def exp_list(tokens):
-            return ast_nodes.ExpList(tokens[1])
-
-        @self.pg.production('expression : expression SYMBOL_LCURL expression SYMBOL_RCURL')
-        def exp_index(tokens):
-            return ast_nodes.ExpIndex(tokens[0],tokens[2])
+        @self.pg.production('expression : statement')
+        def exp_statement(tokens):
+            return(tokens[0])
 
         ## Error Handling ##
         @self.pg.error
diff --git a/tests/19_until.expected b/tests/19_until.expected
new file mode 100644
index 0000000..8b1acc1
--- /dev/null
+++ b/tests/19_until.expected
@@ -0,0 +1,10 @@
+0
+1
+2
+3
+4
+5
+6
+7
+8
+9
diff --git a/tests/19_until.plthy b/tests/19_until.plthy
new file mode 100644
index 0000000..748eeee
--- /dev/null
+++ b/tests/19_until.plthy
@@ -0,0 +1,7 @@
+hello|
+set 0 -> x|
+do [
+    do print<variable x;>|
+    set variable x+1 -> x|
+] until variable x = 10|
+goodbye|
\ No newline at end of file