diff --git a/requirements.txt b/requirements.txt
index 796b440..3adac30 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,3 +1,3 @@
-antlr=4.13.1=ha770c72_0
-antlr4-tools=0.2.1=pypi_0
-ply=3.11=py311h06a4308_0
+antlr4-tools>=0.2.1
+ply>=3.11
+antlr4-python3-runtime>=4.9
diff --git a/src/ArithLexer.interp b/src/ArithLexer.interp
new file mode 100644
index 0000000..9f6a130
--- /dev/null
+++ b/src/ArithLexer.interp
@@ -0,0 +1,38 @@
+token literal names:
+null
+'+'
+'*'
+'**'
+'('
+')'
+null
+null
+
+token symbolic names:
+null
+null
+null
+null
+null
+null
+NUMBER
+WS
+
+rule names:
+T__0
+T__1
+T__2
+T__3
+T__4
+NUMBER
+WS
+
+channel names:
+DEFAULT_TOKEN_CHANNEL
+HIDDEN
+
+mode names:
+DEFAULT_MODE
+
+atn:
+[4, 0, 7, 40, 6, -1, 2, 0, 7, 0, 2, 1, 7, 1, 2, 2, 7, 2, 2, 3, 7, 3, 2, 4, 7, 4, 2, 5, 7, 5, 2, 6, 7, 6, 1, 0, 1, 0, 1, 1, 1, 1, 1, 2, 1, 2, 1, 2, 1, 3, 1, 3, 1, 4, 1, 4, 1, 5, 1, 5, 1, 5, 5, 5, 30, 8, 5, 10, 5, 12, 5, 33, 9, 5, 3, 5, 35, 8, 5, 1, 6, 1, 6, 1, 6, 1, 6, 0, 0, 7, 1, 1, 3, 2, 5, 3, 7, 4, 9, 5, 11, 6, 13, 7, 1, 0, 3, 1, 0, 49, 57, 1, 0, 48, 57, 3, 0, 9, 10, 13, 13, 32, 32, 41, 0, 1, 1, 0, 0, 0, 0, 3, 1, 0, 0, 0, 0, 5, 1, 0, 0, 0, 0, 7, 1, 0, 0, 0, 0, 9, 1, 0, 0, 0, 0, 11, 1, 0, 0, 0, 0, 13, 1, 0, 0, 0, 1, 15, 1, 0, 0, 0, 3, 17, 1, 0, 0, 0, 5, 19, 1, 0, 0, 0, 7, 22, 1, 0, 0, 0, 9, 24, 1, 0, 0, 0, 11, 34, 1, 0, 0, 0, 13, 36, 1, 0, 0, 0, 15, 16, 5, 43, 0, 0, 16, 2, 1, 0, 0, 0, 17, 18, 5, 42, 0, 0, 18, 4, 1, 0, 0, 0, 19, 20, 5, 42, 0, 0, 20, 21, 5, 42, 0, 0, 21, 6, 1, 0, 0, 0, 22, 23, 5, 40, 0, 0, 23, 8, 1, 0, 0, 0, 24, 25, 5, 41, 0, 0, 25, 10, 1, 0, 0, 0, 26, 35, 5, 48, 0, 0, 27, 31, 7, 0, 0, 0, 28, 30, 7, 1, 0, 0, 29, 28, 1, 0, 0, 0, 30, 33, 1, 0, 0, 0, 31, 29, 1, 0, 0, 0, 31, 32, 1, 0, 0, 0, 32, 35, 1, 0, 0, 0, 33, 31, 1, 0, 0, 0, 34, 26, 1, 0, 0, 0, 34, 27, 1, 0, 0, 0, 35, 12, 1, 0, 0, 0, 36, 37, 7, 2, 0, 0, 37, 38, 1, 0, 0, 0, 38, 39, 6, 6, 0, 0, 39, 14, 1, 0, 0, 0, 3, 0, 31, 34, 1, 6, 0, 0]
\ No newline at end of file
diff --git a/src/ArithLexer.py b/src/ArithLexer.py
new file mode 100644
index 0000000..55e067a
--- /dev/null
+++ b/src/ArithLexer.py
@@ -0,0 +1,64 @@
+# Generated from arith.g4 by ANTLR 4.13.1
+from antlr4 import *
+from io import StringIO
+import sys
+if sys.version_info[1] > 5:
+    from typing import TextIO
+else:
+    from typing.io import TextIO
+
+
+def serializedATN():
+    return [
+        4,0,7,40,6,-1,2,0,7,0,2,1,7,1,2,2,7,2,2,3,7,3,2,4,7,4,2,5,7,5,2,
+        6,7,6,1,0,1,0,1,1,1,1,1,2,1,2,1,2,1,3,1,3,1,4,1,4,1,5,1,5,1,5,5,
+        5,30,8,5,10,5,12,5,33,9,5,3,5,35,8,5,1,6,1,6,1,6,1,6,0,0,7,1,1,3,
+        2,5,3,7,4,9,5,11,6,13,7,1,0,3,1,0,49,57,1,0,48,57,3,0,9,10,13,13,
+        32,32,41,0,1,1,0,0,0,0,3,1,0,0,0,0,5,1,0,0,0,0,7,1,0,0,0,0,9,1,0,
+        0,0,0,11,1,0,0,0,0,13,1,0,0,0,1,15,1,0,0,0,3,17,1,0,0,0,5,19,1,0,
+        0,0,7,22,1,0,0,0,9,24,1,0,0,0,11,34,1,0,0,0,13,36,1,0,0,0,15,16,
+        5,43,0,0,16,2,1,0,0,0,17,18,5,42,0,0,18,4,1,0,0,0,19,20,5,42,0,0,
+        20,21,5,42,0,0,21,6,1,0,0,0,22,23,5,40,0,0,23,8,1,0,0,0,24,25,5,
+        41,0,0,25,10,1,0,0,0,26,35,5,48,0,0,27,31,7,0,0,0,28,30,7,1,0,0,
+        29,28,1,0,0,0,30,33,1,0,0,0,31,29,1,0,0,0,31,32,1,0,0,0,32,35,1,
+        0,0,0,33,31,1,0,0,0,34,26,1,0,0,0,34,27,1,0,0,0,35,12,1,0,0,0,36,
+        37,7,2,0,0,37,38,1,0,0,0,38,39,6,6,0,0,39,14,1,0,0,0,3,0,31,34,1,
+        6,0,0
+    ]
+
+class ArithLexer(Lexer):
+
+    atn = ATNDeserializer().deserialize(serializedATN())
+
+    decisionsToDFA = [ DFA(ds, i) for i, ds in enumerate(atn.decisionToState) ]
+
+    T__0 = 1
+    T__1 = 2
+    T__2 = 3
+    T__3 = 4
+    T__4 = 5
+    NUMBER = 6
+    WS = 7
+
+    channelNames = [ u"DEFAULT_TOKEN_CHANNEL", u"HIDDEN" ]
+
+    modeNames = [ "DEFAULT_MODE" ]
+
+    literalNames = [ "<INVALID>",
+            "'+'", "'*'", "'**'", "'('", "')'" ]
+
+    symbolicNames = [ "<INVALID>",
+            "NUMBER", "WS" ]
+
+    ruleNames = [ "T__0", "T__1", "T__2", "T__3", "T__4", "NUMBER", "WS" ]
+
+    grammarFileName = "arith.g4"
+
+    def __init__(self, input=None, output:TextIO = sys.stdout):
+        super().__init__(input, output)
+        self.checkVersion("4.13.1")
+        self._interp = LexerATNSimulator(self, self.atn, self.decisionsToDFA, PredictionContextCache())
+        self._actions = None
+        self._predicates = None
+
+
diff --git a/src/ArithLexer.tokens b/src/ArithLexer.tokens
new file mode 100644
index 0000000..d3047b4
--- /dev/null
+++ b/src/ArithLexer.tokens
@@ -0,0 +1,12 @@
+T__0=1
+T__1=2
+T__2=3
+T__3=4
+T__4=5
+NUMBER=6
+WS=7
+'+'=1
+'*'=2
+'**'=3
+'('=4
+')'=5
diff --git a/src/PowerLexer.interp b/src/PowerLexer.interp
new file mode 100644
index 0000000..9f6a130
--- /dev/null
+++ b/src/PowerLexer.interp
@@ -0,0 +1,38 @@
+token literal names:
+null
+'+'
+'*'
+'**'
+'('
+')'
+null
+null
+
+token symbolic names:
+null
+null
+null
+null
+null
+null
+NUMBER
+WS
+
+rule names:
+T__0
+T__1
+T__2
+T__3
+T__4
+NUMBER
+WS
+
+channel names:
+DEFAULT_TOKEN_CHANNEL
+HIDDEN
+
+mode names:
+DEFAULT_MODE
+
+atn:
+[4, 0, 7, 40, 6, -1, 2, 0, 7, 0, 2, 1, 7, 1, 2, 2, 7, 2, 2, 3, 7, 3, 2, 4, 7, 4, 2, 5, 7, 5, 2, 6, 7, 6, 1, 0, 1, 0, 1, 1, 1, 1, 1, 2, 1, 2, 1, 2, 1, 3, 1, 3, 1, 4, 1, 4, 1, 5, 1, 5, 1, 5, 5, 5, 30, 8, 5, 10, 5, 12, 5, 33, 9, 5, 3, 5, 35, 8, 5, 1, 6, 1, 6, 1, 6, 1, 6, 0, 0, 7, 1, 1, 3, 2, 5, 3, 7, 4, 9, 5, 11, 6, 13, 7, 1, 0, 3, 1, 0, 49, 57, 1, 0, 48, 57, 3, 0, 9, 10, 13, 13, 32, 32, 41, 0, 1, 1, 0, 0, 0, 0, 3, 1, 0, 0, 0, 0, 5, 1, 0, 0, 0, 0, 7, 1, 0, 0, 0, 0, 9, 1, 0, 0, 0, 0, 11, 1, 0, 0, 0, 0, 13, 1, 0, 0, 0, 1, 15, 1, 0, 0, 0, 3, 17, 1, 0, 0, 0, 5, 19, 1, 0, 0, 0, 7, 22, 1, 0, 0, 0, 9, 24, 1, 0, 0, 0, 11, 34, 1, 0, 0, 0, 13, 36, 1, 0, 0, 0, 15, 16, 5, 43, 0, 0, 16, 2, 1, 0, 0, 0, 17, 18, 5, 42, 0, 0, 18, 4, 1, 0, 0, 0, 19, 20, 5, 42, 0, 0, 20, 21, 5, 42, 0, 0, 21, 6, 1, 0, 0, 0, 22, 23, 5, 40, 0, 0, 23, 8, 1, 0, 0, 0, 24, 25, 5, 41, 0, 0, 25, 10, 1, 0, 0, 0, 26, 35, 5, 48, 0, 0, 27, 31, 7, 0, 0, 0, 28, 30, 7, 1, 0, 0, 29, 28, 1, 0, 0, 0, 30, 33, 1, 0, 0, 0, 31, 29, 1, 0, 0, 0, 31, 32, 1, 0, 0, 0, 32, 35, 1, 0, 0, 0, 33, 31, 1, 0, 0, 0, 34, 26, 1, 0, 0, 0, 34, 27, 1, 0, 0, 0, 35, 12, 1, 0, 0, 0, 36, 37, 7, 2, 0, 0, 37, 38, 1, 0, 0, 0, 38, 39, 6, 6, 0, 0, 39, 14, 1, 0, 0, 0, 3, 0, 31, 34, 1, 6, 0, 0]
\ No newline at end of file
diff --git a/src/PowerLexer.py b/src/PowerLexer.py
new file mode 100644
index 0000000..400bfad
--- /dev/null
+++ b/src/PowerLexer.py
@@ -0,0 +1,64 @@
+# Generated from arith.g4 by ANTLR 4.13.1
+from antlr4 import *
+from io import StringIO
+import sys
+if sys.version_info[1] > 5:
+    from typing import TextIO
+else:
+    from typing.io import TextIO
+
+
+def serializedATN():
+    return [
+        4,0,7,40,6,-1,2,0,7,0,2,1,7,1,2,2,7,2,2,3,7,3,2,4,7,4,2,5,7,5,2,
+        6,7,6,1,0,1,0,1,1,1,1,1,2,1,2,1,2,1,3,1,3,1,4,1,4,1,5,1,5,1,5,5,
+        5,30,8,5,10,5,12,5,33,9,5,3,5,35,8,5,1,6,1,6,1,6,1,6,0,0,7,1,1,3,
+        2,5,3,7,4,9,5,11,6,13,7,1,0,3,1,0,49,57,1,0,48,57,3,0,9,10,13,13,
+        32,32,41,0,1,1,0,0,0,0,3,1,0,0,0,0,5,1,0,0,0,0,7,1,0,0,0,0,9,1,0,
+        0,0,0,11,1,0,0,0,0,13,1,0,0,0,1,15,1,0,0,0,3,17,1,0,0,0,5,19,1,0,
+        0,0,7,22,1,0,0,0,9,24,1,0,0,0,11,34,1,0,0,0,13,36,1,0,0,0,15,16,
+        5,43,0,0,16,2,1,0,0,0,17,18,5,42,0,0,18,4,1,0,0,0,19,20,5,42,0,0,
+        20,21,5,42,0,0,21,6,1,0,0,0,22,23,5,40,0,0,23,8,1,0,0,0,24,25,5,
+        41,0,0,25,10,1,0,0,0,26,35,5,48,0,0,27,31,7,0,0,0,28,30,7,1,0,0,
+        29,28,1,0,0,0,30,33,1,0,0,0,31,29,1,0,0,0,31,32,1,0,0,0,32,35,1,
+        0,0,0,33,31,1,0,0,0,34,26,1,0,0,0,34,27,1,0,0,0,35,12,1,0,0,0,36,
+        37,7,2,0,0,37,38,1,0,0,0,38,39,6,6,0,0,39,14,1,0,0,0,3,0,31,34,1,
+        6,0,0
+    ]
+
+class PowerLexer(Lexer):
+
+    atn = ATNDeserializer().deserialize(serializedATN())
+
+    decisionsToDFA = [ DFA(ds, i) for i, ds in enumerate(atn.decisionToState) ]
+
+    T__0 = 1
+    T__1 = 2
+    T__2 = 3
+    T__3 = 4
+    T__4 = 5
+    NUMBER = 6
+    WS = 7
+
+    channelNames = [ u"DEFAULT_TOKEN_CHANNEL", u"HIDDEN" ]
+
+    modeNames = [ "DEFAULT_MODE" ]
+
+    literalNames = [ "<INVALID>",
+            "'+'", "'*'", "'**'", "'('", "')'" ]
+
+    symbolicNames = [ "<INVALID>",
+            "NUMBER", "WS" ]
+
+    ruleNames = [ "T__0", "T__1", "T__2", "T__3", "T__4", "NUMBER", "WS" ]
+
+    grammarFileName = "arith.g4"
+
+    def __init__(self, input=None, output:TextIO = sys.stdout):
+        super().__init__(input, output)
+        self.checkVersion("4.13.1")
+        self._interp = LexerATNSimulator(self, self.atn, self.decisionsToDFA, PredictionContextCache())
+        self._actions = None
+        self._predicates = None
+
+
diff --git a/src/PowerLexer.tokens b/src/PowerLexer.tokens
new file mode 100644
index 0000000..d3047b4
--- /dev/null
+++ b/src/PowerLexer.tokens
@@ -0,0 +1,12 @@
+T__0=1
+T__1=2
+T__2=3
+T__3=4
+T__4=5
+NUMBER=6
+WS=7
+'+'=1
+'*'=2
+'**'=3
+'('=4
+')'=5
diff --git a/src/arith-antlr.py b/src/arith-antlr.py
new file mode 100644
index 0000000..fdec1f0
--- /dev/null
+++ b/src/arith-antlr.py
@@ -0,0 +1,17 @@
+# execute this script from src
+# before using it, execute the following command:
+# antlr4 -Dlanguage=Python3 arith.g4
+
+# generated by the above antlr command (theoretically)
+from arithLexer  import arithLexer
+from arithParser import arithParser
+import antlr4
+
+line = input('antlr-arith>> ')
+while line != '':
+    input_stream  = antlr4.InputStream(line)
+    lexer         = arithLexer(input_stream)
+    token_stream  = antlr4.CommonTokenStream(lexer)
+    parser        = arithParser(token_stream)
+    context = parser.start()
+    line    = input('>> ')
diff --git a/src/arith.g4 b/src/arith.g4
new file mode 100644
index 0000000..605c833
--- /dev/null
+++ b/src/arith.g4
@@ -0,0 +1,30 @@
+grammar arith;
+
+program: start+;
+
+start
+    :e=expr {print($e.r)}
+    ;
+
+expr returns [r]
+    :e=expr '+' p=prod {$r = $e.r + $p.r}
+    |p=prod            {$r = $p.r}
+    ;
+
+prod returns [r]
+    :p=prod '*' pw=pow {$r = $p.r * $pw.r}
+    |pw=pow            {$r = $pw.r}
+    ;
+
+pow returns [r]
+    :b=base '**' pw=pow   {$r = $b.r ** $pw.r}
+    |b=base               {$r = $b.r}
+    ;
+
+base returns [r]
+    :'('e= expr')' {$r = $e.r}
+    |n=NUMBER      {$r = int($n.text)}
+    ;
+
+NUMBER: '0'|[1-9][0-9]*;
+WS: [ \t\n\r] -> skip;
diff --git a/src/arith.interp b/src/arith.interp
new file mode 100644
index 0000000..e616ac4
--- /dev/null
+++ b/src/arith.interp
@@ -0,0 +1,31 @@
+token literal names:
+null
+'+'
+'*'
+'**'
+'('
+')'
+null
+null
+
+token symbolic names:
+null
+null
+null
+null
+null
+null
+NUMBER
+WS
+
+rule names:
+program
+start
+expr
+prod
+pow
+base
+
+
+atn:
+[4, 1, 7, 68, 2, 0, 7, 0, 2, 1, 7, 1, 2, 2, 7, 2, 2, 3, 7, 3, 2, 4, 7, 4, 2, 5, 7, 5, 1, 0, 4, 0, 14, 8, 0, 11, 0, 12, 0, 15, 1, 1, 1, 1, 1, 1, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 5, 2, 30, 8, 2, 10, 2, 12, 2, 33, 9, 2, 1, 3, 1, 3, 1, 3, 1, 3, 1, 3, 1, 3, 1, 3, 1, 3, 1, 3, 5, 3, 44, 8, 3, 10, 3, 12, 3, 47, 9, 3, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 1, 4, 3, 4, 57, 8, 4, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 1, 5, 3, 5, 66, 8, 5, 1, 5, 0, 2, 4, 6, 6, 0, 2, 4, 6, 8, 10, 0, 0, 66, 0, 13, 1, 0, 0, 0, 2, 17, 1, 0, 0, 0, 4, 20, 1, 0, 0, 0, 6, 34, 1, 0, 0, 0, 8, 56, 1, 0, 0, 0, 10, 65, 1, 0, 0, 0, 12, 14, 3, 2, 1, 0, 13, 12, 1, 0, 0, 0, 14, 15, 1, 0, 0, 0, 15, 13, 1, 0, 0, 0, 15, 16, 1, 0, 0, 0, 16, 1, 1, 0, 0, 0, 17, 18, 3, 4, 2, 0, 18, 19, 6, 1, -1, 0, 19, 3, 1, 0, 0, 0, 20, 21, 6, 2, -1, 0, 21, 22, 3, 6, 3, 0, 22, 23, 6, 2, -1, 0, 23, 31, 1, 0, 0, 0, 24, 25, 10, 2, 0, 0, 25, 26, 5, 1, 0, 0, 26, 27, 3, 6, 3, 0, 27, 28, 6, 2, -1, 0, 28, 30, 1, 0, 0, 0, 29, 24, 1, 0, 0, 0, 30, 33, 1, 0, 0, 0, 31, 29, 1, 0, 0, 0, 31, 32, 1, 0, 0, 0, 32, 5, 1, 0, 0, 0, 33, 31, 1, 0, 0, 0, 34, 35, 6, 3, -1, 0, 35, 36, 3, 8, 4, 0, 36, 37, 6, 3, -1, 0, 37, 45, 1, 0, 0, 0, 38, 39, 10, 2, 0, 0, 39, 40, 5, 2, 0, 0, 40, 41, 3, 8, 4, 0, 41, 42, 6, 3, -1, 0, 42, 44, 1, 0, 0, 0, 43, 38, 1, 0, 0, 0, 44, 47, 1, 0, 0, 0, 45, 43, 1, 0, 0, 0, 45, 46, 1, 0, 0, 0, 46, 7, 1, 0, 0, 0, 47, 45, 1, 0, 0, 0, 48, 49, 3, 10, 5, 0, 49, 50, 5, 3, 0, 0, 50, 51, 3, 8, 4, 0, 51, 52, 6, 4, -1, 0, 52, 57, 1, 0, 0, 0, 53, 54, 3, 10, 5, 0, 54, 55, 6, 4, -1, 0, 55, 57, 1, 0, 0, 0, 56, 48, 1, 0, 0, 0, 56, 53, 1, 0, 0, 0, 57, 9, 1, 0, 0, 0, 58, 59, 5, 4, 0, 0, 59, 60, 3, 4, 2, 0, 60, 61, 5, 5, 0, 0, 61, 62, 6, 5, -1, 0, 62, 66, 1, 0, 0, 0, 63, 64, 5, 6, 0, 0, 64, 66, 6, 5, -1, 0, 65, 58, 1, 0, 0, 0, 65, 63, 1, 0, 0, 0, 66, 11, 1, 0, 0, 0, 5, 15, 31, 45, 56, 65]
\ No newline at end of file
diff --git a/src/arith.tokens b/src/arith.tokens
new file mode 100644
index 0000000..d3047b4
--- /dev/null
+++ b/src/arith.tokens
@@ -0,0 +1,12 @@
+T__0=1
+T__1=2
+T__2=3
+T__3=4
+T__4=5
+NUMBER=6
+WS=7
+'+'=1
+'*'=2
+'**'=3
+'('=4
+')'=5
diff --git a/src/arithLexer.interp b/src/arithLexer.interp
new file mode 100644
index 0000000..9f6a130
--- /dev/null
+++ b/src/arithLexer.interp
@@ -0,0 +1,38 @@
+token literal names:
+null
+'+'
+'*'
+'**'
+'('
+')'
+null
+null
+
+token symbolic names:
+null
+null
+null
+null
+null
+null
+NUMBER
+WS
+
+rule names:
+T__0
+T__1
+T__2
+T__3
+T__4
+NUMBER
+WS
+
+channel names:
+DEFAULT_TOKEN_CHANNEL
+HIDDEN
+
+mode names:
+DEFAULT_MODE
+
+atn:
+[4, 0, 7, 40, 6, -1, 2, 0, 7, 0, 2, 1, 7, 1, 2, 2, 7, 2, 2, 3, 7, 3, 2, 4, 7, 4, 2, 5, 7, 5, 2, 6, 7, 6, 1, 0, 1, 0, 1, 1, 1, 1, 1, 2, 1, 2, 1, 2, 1, 3, 1, 3, 1, 4, 1, 4, 1, 5, 1, 5, 1, 5, 5, 5, 30, 8, 5, 10, 5, 12, 5, 33, 9, 5, 3, 5, 35, 8, 5, 1, 6, 1, 6, 1, 6, 1, 6, 0, 0, 7, 1, 1, 3, 2, 5, 3, 7, 4, 9, 5, 11, 6, 13, 7, 1, 0, 3, 1, 0, 49, 57, 1, 0, 48, 57, 3, 0, 9, 10, 13, 13, 32, 32, 41, 0, 1, 1, 0, 0, 0, 0, 3, 1, 0, 0, 0, 0, 5, 1, 0, 0, 0, 0, 7, 1, 0, 0, 0, 0, 9, 1, 0, 0, 0, 0, 11, 1, 0, 0, 0, 0, 13, 1, 0, 0, 0, 1, 15, 1, 0, 0, 0, 3, 17, 1, 0, 0, 0, 5, 19, 1, 0, 0, 0, 7, 22, 1, 0, 0, 0, 9, 24, 1, 0, 0, 0, 11, 34, 1, 0, 0, 0, 13, 36, 1, 0, 0, 0, 15, 16, 5, 43, 0, 0, 16, 2, 1, 0, 0, 0, 17, 18, 5, 42, 0, 0, 18, 4, 1, 0, 0, 0, 19, 20, 5, 42, 0, 0, 20, 21, 5, 42, 0, 0, 21, 6, 1, 0, 0, 0, 22, 23, 5, 40, 0, 0, 23, 8, 1, 0, 0, 0, 24, 25, 5, 41, 0, 0, 25, 10, 1, 0, 0, 0, 26, 35, 5, 48, 0, 0, 27, 31, 7, 0, 0, 0, 28, 30, 7, 1, 0, 0, 29, 28, 1, 0, 0, 0, 30, 33, 1, 0, 0, 0, 31, 29, 1, 0, 0, 0, 31, 32, 1, 0, 0, 0, 32, 35, 1, 0, 0, 0, 33, 31, 1, 0, 0, 0, 34, 26, 1, 0, 0, 0, 34, 27, 1, 0, 0, 0, 35, 12, 1, 0, 0, 0, 36, 37, 7, 2, 0, 0, 37, 38, 1, 0, 0, 0, 38, 39, 6, 6, 0, 0, 39, 14, 1, 0, 0, 0, 3, 0, 31, 34, 1, 6, 0, 0]
\ No newline at end of file
diff --git a/src/arithLexer.py b/src/arithLexer.py
new file mode 100644
index 0000000..ecd5f9c
--- /dev/null
+++ b/src/arithLexer.py
@@ -0,0 +1,64 @@
+# Generated from arith.g4 by ANTLR 4.13.1
+from antlr4 import *
+from io import StringIO
+import sys
+if sys.version_info[1] > 5:
+    from typing import TextIO
+else:
+    from typing.io import TextIO
+
+
+def serializedATN():
+    return [
+        4,0,7,40,6,-1,2,0,7,0,2,1,7,1,2,2,7,2,2,3,7,3,2,4,7,4,2,5,7,5,2,
+        6,7,6,1,0,1,0,1,1,1,1,1,2,1,2,1,2,1,3,1,3,1,4,1,4,1,5,1,5,1,5,5,
+        5,30,8,5,10,5,12,5,33,9,5,3,5,35,8,5,1,6,1,6,1,6,1,6,0,0,7,1,1,3,
+        2,5,3,7,4,9,5,11,6,13,7,1,0,3,1,0,49,57,1,0,48,57,3,0,9,10,13,13,
+        32,32,41,0,1,1,0,0,0,0,3,1,0,0,0,0,5,1,0,0,0,0,7,1,0,0,0,0,9,1,0,
+        0,0,0,11,1,0,0,0,0,13,1,0,0,0,1,15,1,0,0,0,3,17,1,0,0,0,5,19,1,0,
+        0,0,7,22,1,0,0,0,9,24,1,0,0,0,11,34,1,0,0,0,13,36,1,0,0,0,15,16,
+        5,43,0,0,16,2,1,0,0,0,17,18,5,42,0,0,18,4,1,0,0,0,19,20,5,42,0,0,
+        20,21,5,42,0,0,21,6,1,0,0,0,22,23,5,40,0,0,23,8,1,0,0,0,24,25,5,
+        41,0,0,25,10,1,0,0,0,26,35,5,48,0,0,27,31,7,0,0,0,28,30,7,1,0,0,
+        29,28,1,0,0,0,30,33,1,0,0,0,31,29,1,0,0,0,31,32,1,0,0,0,32,35,1,
+        0,0,0,33,31,1,0,0,0,34,26,1,0,0,0,34,27,1,0,0,0,35,12,1,0,0,0,36,
+        37,7,2,0,0,37,38,1,0,0,0,38,39,6,6,0,0,39,14,1,0,0,0,3,0,31,34,1,
+        6,0,0
+    ]
+
+class arithLexer(Lexer):
+
+    atn = ATNDeserializer().deserialize(serializedATN())
+
+    decisionsToDFA = [ DFA(ds, i) for i, ds in enumerate(atn.decisionToState) ]
+
+    T__0 = 1
+    T__1 = 2
+    T__2 = 3
+    T__3 = 4
+    T__4 = 5
+    NUMBER = 6
+    WS = 7
+
+    channelNames = [ u"DEFAULT_TOKEN_CHANNEL", u"HIDDEN" ]
+
+    modeNames = [ "DEFAULT_MODE" ]
+
+    literalNames = [ "<INVALID>",
+            "'+'", "'*'", "'**'", "'('", "')'" ]
+
+    symbolicNames = [ "<INVALID>",
+            "NUMBER", "WS" ]
+
+    ruleNames = [ "T__0", "T__1", "T__2", "T__3", "T__4", "NUMBER", "WS" ]
+
+    grammarFileName = "arith.g4"
+
+    def __init__(self, input=None, output:TextIO = sys.stdout):
+        super().__init__(input, output)
+        self.checkVersion("4.13.1")
+        self._interp = LexerATNSimulator(self, self.atn, self.decisionsToDFA, PredictionContextCache())
+        self._actions = None
+        self._predicates = None
+
+
diff --git a/src/arithLexer.tokens b/src/arithLexer.tokens
new file mode 100644
index 0000000..d3047b4
--- /dev/null
+++ b/src/arithLexer.tokens
@@ -0,0 +1,12 @@
+T__0=1
+T__1=2
+T__2=3
+T__3=4
+T__4=5
+NUMBER=6
+WS=7
+'+'=1
+'*'=2
+'**'=3
+'('=4
+')'=5
diff --git a/src/arithListener.py b/src/arithListener.py
new file mode 100644
index 0000000..3732ff1
--- /dev/null
+++ b/src/arithListener.py
@@ -0,0 +1,66 @@
+# Generated from arith.g4 by ANTLR 4.13.1
+from antlr4 import *
+if "." in __name__:
+    from .arithParser import arithParser
+else:
+    from arithParser import arithParser
+
+# This class defines a complete listener for a parse tree produced by arithParser.
+class arithListener(ParseTreeListener):
+
+    # Enter a parse tree produced by arithParser#program.
+    def enterProgram(self, ctx:arithParser.ProgramContext):
+        pass
+
+    # Exit a parse tree produced by arithParser#program.
+    def exitProgram(self, ctx:arithParser.ProgramContext):
+        pass
+
+
+    # Enter a parse tree produced by arithParser#start.
+    def enterStart(self, ctx:arithParser.StartContext):
+        pass
+
+    # Exit a parse tree produced by arithParser#start.
+    def exitStart(self, ctx:arithParser.StartContext):
+        pass
+
+
+    # Enter a parse tree produced by arithParser#expr.
+    def enterExpr(self, ctx:arithParser.ExprContext):
+        pass
+
+    # Exit a parse tree produced by arithParser#expr.
+    def exitExpr(self, ctx:arithParser.ExprContext):
+        pass
+
+
+    # Enter a parse tree produced by arithParser#prod.
+    def enterProd(self, ctx:arithParser.ProdContext):
+        pass
+
+    # Exit a parse tree produced by arithParser#prod.
+    def exitProd(self, ctx:arithParser.ProdContext):
+        pass
+
+
+    # Enter a parse tree produced by arithParser#pow.
+    def enterPow(self, ctx:arithParser.PowContext):
+        pass
+
+    # Exit a parse tree produced by arithParser#pow.
+    def exitPow(self, ctx:arithParser.PowContext):
+        pass
+
+
+    # Enter a parse tree produced by arithParser#base.
+    def enterBase(self, ctx:arithParser.BaseContext):
+        pass
+
+    # Exit a parse tree produced by arithParser#base.
+    def exitBase(self, ctx:arithParser.BaseContext):
+        pass
+
+
+
+del arithParser
\ No newline at end of file
diff --git a/src/arithParser.py b/src/arithParser.py
new file mode 100644
index 0000000..4a2816c
--- /dev/null
+++ b/src/arithParser.py
@@ -0,0 +1,490 @@
+# Generated from arith.g4 by ANTLR 4.13.1
+# encoding: utf-8
+from antlr4 import *
+from io import StringIO
+import sys
+if sys.version_info[1] > 5:
+	from typing import TextIO
+else:
+	from typing.io import TextIO
+
+def serializedATN():
+    return [
+        4,1,7,68,2,0,7,0,2,1,7,1,2,2,7,2,2,3,7,3,2,4,7,4,2,5,7,5,1,0,4,0,
+        14,8,0,11,0,12,0,15,1,1,1,1,1,1,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,
+        1,2,5,2,30,8,2,10,2,12,2,33,9,2,1,3,1,3,1,3,1,3,1,3,1,3,1,3,1,3,
+        1,3,5,3,44,8,3,10,3,12,3,47,9,3,1,4,1,4,1,4,1,4,1,4,1,4,1,4,1,4,
+        3,4,57,8,4,1,5,1,5,1,5,1,5,1,5,1,5,1,5,3,5,66,8,5,1,5,0,2,4,6,6,
+        0,2,4,6,8,10,0,0,66,0,13,1,0,0,0,2,17,1,0,0,0,4,20,1,0,0,0,6,34,
+        1,0,0,0,8,56,1,0,0,0,10,65,1,0,0,0,12,14,3,2,1,0,13,12,1,0,0,0,14,
+        15,1,0,0,0,15,13,1,0,0,0,15,16,1,0,0,0,16,1,1,0,0,0,17,18,3,4,2,
+        0,18,19,6,1,-1,0,19,3,1,0,0,0,20,21,6,2,-1,0,21,22,3,6,3,0,22,23,
+        6,2,-1,0,23,31,1,0,0,0,24,25,10,2,0,0,25,26,5,1,0,0,26,27,3,6,3,
+        0,27,28,6,2,-1,0,28,30,1,0,0,0,29,24,1,0,0,0,30,33,1,0,0,0,31,29,
+        1,0,0,0,31,32,1,0,0,0,32,5,1,0,0,0,33,31,1,0,0,0,34,35,6,3,-1,0,
+        35,36,3,8,4,0,36,37,6,3,-1,0,37,45,1,0,0,0,38,39,10,2,0,0,39,40,
+        5,2,0,0,40,41,3,8,4,0,41,42,6,3,-1,0,42,44,1,0,0,0,43,38,1,0,0,0,
+        44,47,1,0,0,0,45,43,1,0,0,0,45,46,1,0,0,0,46,7,1,0,0,0,47,45,1,0,
+        0,0,48,49,3,10,5,0,49,50,5,3,0,0,50,51,3,8,4,0,51,52,6,4,-1,0,52,
+        57,1,0,0,0,53,54,3,10,5,0,54,55,6,4,-1,0,55,57,1,0,0,0,56,48,1,0,
+        0,0,56,53,1,0,0,0,57,9,1,0,0,0,58,59,5,4,0,0,59,60,3,4,2,0,60,61,
+        5,5,0,0,61,62,6,5,-1,0,62,66,1,0,0,0,63,64,5,6,0,0,64,66,6,5,-1,
+        0,65,58,1,0,0,0,65,63,1,0,0,0,66,11,1,0,0,0,5,15,31,45,56,65
+    ]
+
+class arithParser ( Parser ):
+
+    grammarFileName = "arith.g4"
+
+    atn = ATNDeserializer().deserialize(serializedATN())
+
+    decisionsToDFA = [ DFA(ds, i) for i, ds in enumerate(atn.decisionToState) ]
+
+    sharedContextCache = PredictionContextCache()
+
+    literalNames = [ "<INVALID>", "'+'", "'*'", "'**'", "'('", "')'" ]
+
+    symbolicNames = [ "<INVALID>", "<INVALID>", "<INVALID>", "<INVALID>", 
+                      "<INVALID>", "<INVALID>", "NUMBER", "WS" ]
+
+    RULE_program = 0
+    RULE_start = 1
+    RULE_expr = 2
+    RULE_prod = 3
+    RULE_pow = 4
+    RULE_base = 5
+
+    ruleNames =  [ "program", "start", "expr", "prod", "pow", "base" ]
+
+    EOF = Token.EOF
+    T__0=1
+    T__1=2
+    T__2=3
+    T__3=4
+    T__4=5
+    NUMBER=6
+    WS=7
+
+    def __init__(self, input:TokenStream, output:TextIO = sys.stdout):
+        super().__init__(input, output)
+        self.checkVersion("4.13.1")
+        self._interp = ParserATNSimulator(self, self.atn, self.decisionsToDFA, self.sharedContextCache)
+        self._predicates = None
+
+
+
+
+    class ProgramContext(ParserRuleContext):
+        __slots__ = 'parser'
+
+        def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
+            super().__init__(parent, invokingState)
+            self.parser = parser
+
+        def start(self, i:int=None):
+            if i is None:
+                return self.getTypedRuleContexts(arithParser.StartContext)
+            else:
+                return self.getTypedRuleContext(arithParser.StartContext,i)
+
+
+        def getRuleIndex(self):
+            return arithParser.RULE_program
+
+        def enterRule(self, listener:ParseTreeListener):
+            if hasattr( listener, "enterProgram" ):
+                listener.enterProgram(self)
+
+        def exitRule(self, listener:ParseTreeListener):
+            if hasattr( listener, "exitProgram" ):
+                listener.exitProgram(self)
+
+
+
+
+    def program(self):
+
+        localctx = arithParser.ProgramContext(self, self._ctx, self.state)
+        self.enterRule(localctx, 0, self.RULE_program)
+        self._la = 0 # Token type
+        try:
+            self.enterOuterAlt(localctx, 1)
+            self.state = 13 
+            self._errHandler.sync(self)
+            _la = self._input.LA(1)
+            while True:
+                self.state = 12
+                self.start()
+                self.state = 15 
+                self._errHandler.sync(self)
+                _la = self._input.LA(1)
+                if not (_la==4 or _la==6):
+                    break
+
+        except RecognitionException as re:
+            localctx.exception = re
+            self._errHandler.reportError(self, re)
+            self._errHandler.recover(self, re)
+        finally:
+            self.exitRule()
+        return localctx
+
+
+    class StartContext(ParserRuleContext):
+        __slots__ = 'parser'
+
+        def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
+            super().__init__(parent, invokingState)
+            self.parser = parser
+            self.e = None # ExprContext
+
+        def expr(self):
+            return self.getTypedRuleContext(arithParser.ExprContext,0)
+
+
+        def getRuleIndex(self):
+            return arithParser.RULE_start
+
+        def enterRule(self, listener:ParseTreeListener):
+            if hasattr( listener, "enterStart" ):
+                listener.enterStart(self)
+
+        def exitRule(self, listener:ParseTreeListener):
+            if hasattr( listener, "exitStart" ):
+                listener.exitStart(self)
+
+
+
+
+    def start(self):
+
+        localctx = arithParser.StartContext(self, self._ctx, self.state)
+        self.enterRule(localctx, 2, self.RULE_start)
+        try:
+            self.enterOuterAlt(localctx, 1)
+            self.state = 17
+            localctx.e = self.expr(0)
+            print(localctx.e.r)
+        except RecognitionException as re:
+            localctx.exception = re
+            self._errHandler.reportError(self, re)
+            self._errHandler.recover(self, re)
+        finally:
+            self.exitRule()
+        return localctx
+
+
+    class ExprContext(ParserRuleContext):
+        __slots__ = 'parser'
+
+        def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
+            super().__init__(parent, invokingState)
+            self.parser = parser
+            self.r = None
+            self.e = None # ExprContext
+            self.p = None # ProdContext
+
+        def prod(self):
+            return self.getTypedRuleContext(arithParser.ProdContext,0)
+
+
+        def expr(self):
+            return self.getTypedRuleContext(arithParser.ExprContext,0)
+
+
+        def getRuleIndex(self):
+            return arithParser.RULE_expr
+
+        def enterRule(self, listener:ParseTreeListener):
+            if hasattr( listener, "enterExpr" ):
+                listener.enterExpr(self)
+
+        def exitRule(self, listener:ParseTreeListener):
+            if hasattr( listener, "exitExpr" ):
+                listener.exitExpr(self)
+
+
+
+    def expr(self, _p:int=0):
+        _parentctx = self._ctx
+        _parentState = self.state
+        localctx = arithParser.ExprContext(self, self._ctx, _parentState)
+        _prevctx = localctx
+        _startState = 4
+        self.enterRecursionRule(localctx, 4, self.RULE_expr, _p)
+        try:
+            self.enterOuterAlt(localctx, 1)
+            self.state = 21
+            localctx.p = self.prod(0)
+            localctx.r = localctx.p.r
+            self._ctx.stop = self._input.LT(-1)
+            self.state = 31
+            self._errHandler.sync(self)
+            _alt = self._interp.adaptivePredict(self._input,1,self._ctx)
+            while _alt!=2 and _alt!=ATN.INVALID_ALT_NUMBER:
+                if _alt==1:
+                    if self._parseListeners is not None:
+                        self.triggerExitRuleEvent()
+                    _prevctx = localctx
+                    localctx = arithParser.ExprContext(self, _parentctx, _parentState)
+                    localctx.e = _prevctx
+                    self.pushNewRecursionContext(localctx, _startState, self.RULE_expr)
+                    self.state = 24
+                    if not self.precpred(self._ctx, 2):
+                        from antlr4.error.Errors import FailedPredicateException
+                        raise FailedPredicateException(self, "self.precpred(self._ctx, 2)")
+                    self.state = 25
+                    self.match(arithParser.T__0)
+                    self.state = 26
+                    localctx.p = self.prod(0)
+                    localctx.r = localctx.e.r + localctx.p.r 
+                self.state = 33
+                self._errHandler.sync(self)
+                _alt = self._interp.adaptivePredict(self._input,1,self._ctx)
+
+        except RecognitionException as re:
+            localctx.exception = re
+            self._errHandler.reportError(self, re)
+            self._errHandler.recover(self, re)
+        finally:
+            self.unrollRecursionContexts(_parentctx)
+        return localctx
+
+
+    class ProdContext(ParserRuleContext):
+        __slots__ = 'parser'
+
+        def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
+            super().__init__(parent, invokingState)
+            self.parser = parser
+            self.r = None
+            self.p = None # ProdContext
+            self.pw = None # PowContext
+
+        def pow_(self):
+            return self.getTypedRuleContext(arithParser.PowContext,0)
+
+
+        def prod(self):
+            return self.getTypedRuleContext(arithParser.ProdContext,0)
+
+
+        def getRuleIndex(self):
+            return arithParser.RULE_prod
+
+        def enterRule(self, listener:ParseTreeListener):
+            if hasattr( listener, "enterProd" ):
+                listener.enterProd(self)
+
+        def exitRule(self, listener:ParseTreeListener):
+            if hasattr( listener, "exitProd" ):
+                listener.exitProd(self)
+
+
+
+    def prod(self, _p:int=0):
+        _parentctx = self._ctx
+        _parentState = self.state
+        localctx = arithParser.ProdContext(self, self._ctx, _parentState)
+        _prevctx = localctx
+        _startState = 6
+        self.enterRecursionRule(localctx, 6, self.RULE_prod, _p)
+        try:
+            self.enterOuterAlt(localctx, 1)
+            self.state = 35
+            localctx.pw = self.pow_()
+            localctx.r = localctx.pw.r
+            self._ctx.stop = self._input.LT(-1)
+            self.state = 45
+            self._errHandler.sync(self)
+            _alt = self._interp.adaptivePredict(self._input,2,self._ctx)
+            while _alt!=2 and _alt!=ATN.INVALID_ALT_NUMBER:
+                if _alt==1:
+                    if self._parseListeners is not None:
+                        self.triggerExitRuleEvent()
+                    _prevctx = localctx
+                    localctx = arithParser.ProdContext(self, _parentctx, _parentState)
+                    localctx.p = _prevctx
+                    self.pushNewRecursionContext(localctx, _startState, self.RULE_prod)
+                    self.state = 38
+                    if not self.precpred(self._ctx, 2):
+                        from antlr4.error.Errors import FailedPredicateException
+                        raise FailedPredicateException(self, "self.precpred(self._ctx, 2)")
+                    self.state = 39
+                    self.match(arithParser.T__1)
+                    self.state = 40
+                    localctx.pw = self.pow_()
+                    localctx.r = localctx.p.r * localctx.pw.r 
+                self.state = 47
+                self._errHandler.sync(self)
+                _alt = self._interp.adaptivePredict(self._input,2,self._ctx)
+
+        except RecognitionException as re:
+            localctx.exception = re
+            self._errHandler.reportError(self, re)
+            self._errHandler.recover(self, re)
+        finally:
+            self.unrollRecursionContexts(_parentctx)
+        return localctx
+
+
+    class PowContext(ParserRuleContext):
+        __slots__ = 'parser'
+
+        def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
+            super().__init__(parent, invokingState)
+            self.parser = parser
+            self.r = None
+            self.b = None # BaseContext
+            self.pw = None # PowContext
+
+        def base(self):
+            return self.getTypedRuleContext(arithParser.BaseContext,0)
+
+
+        def pow_(self):
+            return self.getTypedRuleContext(arithParser.PowContext,0)
+
+
+        def getRuleIndex(self):
+            return arithParser.RULE_pow
+
+        def enterRule(self, listener:ParseTreeListener):
+            if hasattr( listener, "enterPow" ):
+                listener.enterPow(self)
+
+        def exitRule(self, listener:ParseTreeListener):
+            if hasattr( listener, "exitPow" ):
+                listener.exitPow(self)
+
+
+
+
+    def pow_(self):
+
+        localctx = arithParser.PowContext(self, self._ctx, self.state)
+        self.enterRule(localctx, 8, self.RULE_pow)
+        try:
+            self.state = 56
+            self._errHandler.sync(self)
+            la_ = self._interp.adaptivePredict(self._input,3,self._ctx)
+            if la_ == 1:
+                self.enterOuterAlt(localctx, 1)
+                self.state = 48
+                localctx.b = self.base()
+                self.state = 49
+                self.match(arithParser.T__2)
+                self.state = 50
+                localctx.pw = self.pow_()
+                localctx.r = localctx.b.r ** localctx.pw.r
+                pass
+
+            elif la_ == 2:
+                self.enterOuterAlt(localctx, 2)
+                self.state = 53
+                localctx.b = self.base()
+                localctx.r = localctx.b.r
+                pass
+
+
+        except RecognitionException as re:
+            localctx.exception = re
+            self._errHandler.reportError(self, re)
+            self._errHandler.recover(self, re)
+        finally:
+            self.exitRule()
+        return localctx
+
+
+    class BaseContext(ParserRuleContext):
+        __slots__ = 'parser'
+
+        def __init__(self, parser, parent:ParserRuleContext=None, invokingState:int=-1):
+            super().__init__(parent, invokingState)
+            self.parser = parser
+            self.r = None
+            self.e = None # ExprContext
+            self.n = None # Token
+
+        def expr(self):
+            return self.getTypedRuleContext(arithParser.ExprContext,0)
+
+
+        def NUMBER(self):
+            return self.getToken(arithParser.NUMBER, 0)
+
+        def getRuleIndex(self):
+            return arithParser.RULE_base
+
+        def enterRule(self, listener:ParseTreeListener):
+            if hasattr( listener, "enterBase" ):
+                listener.enterBase(self)
+
+        def exitRule(self, listener:ParseTreeListener):
+            if hasattr( listener, "exitBase" ):
+                listener.exitBase(self)
+
+
+
+
+    def base(self):
+
+        localctx = arithParser.BaseContext(self, self._ctx, self.state)
+        self.enterRule(localctx, 10, self.RULE_base)
+        try:
+            self.state = 65
+            self._errHandler.sync(self)
+            token = self._input.LA(1)
+            if token in [4]:
+                self.enterOuterAlt(localctx, 1)
+                self.state = 58
+                self.match(arithParser.T__3)
+                self.state = 59
+                localctx.e = self.expr(0)
+                self.state = 60
+                self.match(arithParser.T__4)
+                localctx.r = localctx.e.r
+                pass
+            elif token in [6]:
+                self.enterOuterAlt(localctx, 2)
+                self.state = 63
+                localctx.n = self.match(arithParser.NUMBER)
+                localctx.r = int((None if localctx.n is None else localctx.n.text))
+                pass
+            else:
+                raise NoViableAltException(self)
+
+        except RecognitionException as re:
+            localctx.exception = re
+            self._errHandler.reportError(self, re)
+            self._errHandler.recover(self, re)
+        finally:
+            self.exitRule()
+        return localctx
+
+
+
+    def sempred(self, localctx:RuleContext, ruleIndex:int, predIndex:int):
+        if self._predicates == None:
+            self._predicates = dict()
+        self._predicates[2] = self.expr_sempred
+        self._predicates[3] = self.prod_sempred
+        pred = self._predicates.get(ruleIndex, None)
+        if pred is None:
+            raise Exception("No predicate with index:" + str(ruleIndex))
+        else:
+            return pred(localctx, predIndex)
+
+    def expr_sempred(self, localctx:ExprContext, predIndex:int):
+            if predIndex == 0:
+                return self.precpred(self._ctx, 2)
+         
+
+    def prod_sempred(self, localctx:ProdContext, predIndex:int):
+            if predIndex == 1:
+                return self.precpred(self._ctx, 2)
+         
+
+
+
+