diff --git a/grammar/Circom.g4 b/grammar/Circom.g4
index 0605d02..0752645 100644
--- a/grammar/Circom.g4
+++ b/grammar/Circom.g4
@@ -1,5 +1,7 @@
 grammar Circom;
 
+import LexerCircom;
+
 circuit
     :   pragmaDeclaration+ includeDeclaration* blockDeclaration* componentMainDeclaration?
         EOF
@@ -32,14 +34,14 @@ blockDeclaration
     ;
 
 functionDeclaration
-    : 'function' ID '(' args* ')' functionStmt
+    : 'function' ID '(' ARGS* ')' functionStmt
     ;
 
 functionStmt
     : '{' functionStmt* '}'
-    | ID selfOp
+    | ID SELF_OP
     | varDeclaration
-    | expression (assignment | assigmentOp) expression
+    | expression (ASSIGNMENT | ASSIGNMENT_OP) expression
     | 'if' parExpression functionStmt ('else' functionStmt)?
     | 'while' parExpression functionStmt
     | 'for' '(' forControl ')' functionStmt
@@ -48,28 +50,28 @@ functionStmt
     ;
 
 templateDeclaration
-    : 'template' ID '(' args* ')' statement*
-    | 'template' 'custom' ID '(' args* ')' statement*
+    : 'template' ID '(' ARGS* ')' statement*
+    | 'template' 'custom' ID '(' ARGS* ')' statement*
     ;
 
 componentMainDeclaration
-    : 'component' 'main' ('{' 'public' '[' args ']'  '}')? '=' ID '(' intSequence* ')' ';'
+    : 'component' 'main' ('{' 'public' '[' ARGS ']'  '}')? '=' ID '(' INT_SEQUENCE* ')' ';'
     ;
 
 statement
     : '{' statement* '}'
-    | ID selfOp
+    | ID SELF_OP
     | varDeclaration
     | signalDeclaration
     | componentDeclaration
     | blockInstantiation
-    | expression (assignment | constraintEq) expression
-    | (primary | ((ID arrayDimension*) '.' (ID arrayDimension*))) (leftAssignment | assigmentOp) expression
-    | expression rightAssignment primary
-    | '_' (assignment | leftAssignment) (expression | blockInstantiation)
-    | (expression | blockInstantiation) rightAssignment '_'
-    | '(' argsWithUnderscore ')' (assignment | leftAssignment) blockInstantiation
-    | blockInstantiation rightAssignment '(' argsWithUnderscore ')'
+    | expression (ASSIGNMENT | CONSTRATINT_EQ) expression
+    | (primary | (variableDefinition '.' variableDefinition)) (LEFT_ASSIGNMENT | ASSIGNMENT_OP) expression
+    | expression RIGHT_ASSIGNMENT primary
+    | '_' (ASSIGNMENT | LEFT_ASSIGNMENT) (expression | blockInstantiation)
+    | (expression | blockInstantiation) RIGHT_ASSIGNMENT '_'
+    | '(' ARGS_AND_UNDERSCORE ')' (ASSIGNMENT | LEFT_ASSIGNMENT) blockInstantiation
+    | blockInstantiation RIGHT_ASSIGNMENT '(' ARGS_AND_UNDERSCORE ')'
     | 'if' parExpression statement ('else' statement)?
     | 'while' parExpression statement
     | 'for' '(' forControl ')' statement
@@ -79,9 +81,9 @@ statement
 
 forControl: forInit ';' expression ';' forUpdate ;
 
-forInit: varDefinition (assignment rhsValue)? ;
+forInit: varDefinition (ASSIGNMENT rhsValue)? ;
 
-forUpdate: expression | (ID (selfOp | (assignment expression))) ;
+forUpdate: expression | (ID (SELF_OP | (ASSIGNMENT expression))) ;
 
 parExpression: '(' expression ')' ;
 
@@ -103,81 +105,43 @@ expression
 primary
     : '(' expression ')'
     | '[' expression (',' expression)* ']'
-    | intSequence
-    | args
-    | ID arrayDimension*
+    | variableDefinition
+    | INT_SEQUENCE
+    | ARGS
     | INT
     ;
 
 componentDefinition: 'component' ID ;
 
 componentDeclaration
-    : componentDefinition arrayDimension* (assignment blockInstantiation)?
+    : componentDefinition arrayDimension* (ASSIGNMENT blockInstantiation)?
     ;
 
-signalDefinition: 'signal' signalType? ('{' args '}')? ID arrayDimension*;
+signalDefinition: 'signal' signalType? ('{' ARGS '}')? variableDefinition;
 
 signalType: 'input' | 'output' ;
 
 signalDeclaration
-    : signalDefinition (leftAssignment rhsValue)?
-    | signalDefinition (',' ID arrayDimension*)*
+    : signalDefinition (LEFT_ASSIGNMENT rhsValue)?
+    | signalDefinition (',' variableDefinition)*
     ;
 
-varDefinition: 'var' ID arrayDimension* ;
+varDefinition: 'var' variableDefinition ;
 
 varDeclaration
-    : varDefinition (assignment rhsValue)?
-    | varDefinition (',' ID arrayDimension*)*
+    : varDefinition (ASSIGNMENT rhsValue)?
+    | varDefinition (',' variableDefinition)*
     ;
 
-assignment: '=' ;
-
-assigmentOp: '+=' | '-=' | '*=' | '**=' | '/=' | '\\=' | '%=' | '<<=' | '>>=' | '&=' | '^=' | '|=' ;
-
-selfOp: '++' | '--' ;
-
-leftAssignment: '<--' | '<==' ;
-
-rightAssignment: '-->' | '==>' ;
-
-constraintEq: '===' ;
-
 rhsValue: expression | blockInstantiation ;
 
 componentCall
-    : '(' expression (',' expression)* ')'
-    | '(' ID leftAssignment expression (',' ID leftAssignment expression)* ')'
-    | '(' expression rightAssignment ID (',' expression rightAssignment ID)* ')'
+    : '(' LEFT_ASSIGNMENT? expression (',' LEFT_ASSIGNMENT? expression)* ')'
+    | '(' expression RIGHT_ASSIGNMENT ID (',' expression RIGHT_ASSIGNMENT ID)* ')'
     ;
 
 blockInstantiation: ID '(' ((expression)* | (expression (',' expression)*)) ')' componentCall? ;
 
-arrayDimension: '[' (INT | ID | expression) ']' ;
-
-argsWithUnderscore: ('_' | ID) (',' ('_' | ID) )* ;
-
-args: ID (',' ID)* ;
-
-intSequence: INT (',' INT)* ;
-
-ID: '_'* LETTER (LETTER | DIGIT | '_' | '$')* ;             // match identifiers
-
-INT: DIGIT+ ;                                               // match integers
-
-DIGIT: [0-9] ;                                              // match single digit
-
-LETTER: [a-zA-Z] ;                                          // match single letter
-
-COMMENT
-    : '/*' .*? '*/'    -> channel(HIDDEN)                   // match anything between /* and */
-    ;
-
-LINE_COMMENT
-    : '//' ~[\r\n]* '\r'? '\n' -> channel(HIDDEN)
-    ;
-
-WS  : [ \r\t\u000C\n]+ -> channel(HIDDEN)
-    ;
-
+variableDefinition: ID arrayDimension* ;
 
+arrayDimension: '[' expression ']' ;
diff --git a/grammar/LexerCircom.g4 b/grammar/LexerCircom.g4
new file mode 100644
index 0000000..9edb0e3
--- /dev/null
+++ b/grammar/LexerCircom.g4
@@ -0,0 +1,39 @@
+lexer grammar LexerCircom;
+
+ASSIGNMENT: '=' ;
+
+ASSIGNMENT_OP: '+=' | '-=' | '*=' | '**=' | '/=' | '\\=' | '%=' | '<<=' | '>>=' | '&=' | '^=' | '|=' ;
+
+SELF_OP: '++' | '--' ;
+
+LEFT_ASSIGNMENT: '<--' | '<==' ;
+
+RIGHT_ASSIGNMENT: '-->' | '==>' ;
+
+CONSTRATINT_EQ: '===' ;
+
+ARGS_AND_UNDERSCORE: ('_' | ID) (',' ('_' | ID) )* ;
+
+ARGS: ID (',' ID)* ;
+
+INT_SEQUENCE: INT (',' INT)* ;
+
+ID: '_'* LETTER (LETTER | DIGIT | '_' | '$')* ;              // match identifiers
+
+INT: DIGIT+ ;                                                // match integers
+
+DIGIT: [0-9] ;                                               // match single digit
+
+LETTER: [a-zA-Z] ;                                           // match single letter
+
+COMMENT
+    : '/*' .*? '*/'             -> channel(HIDDEN)           // match anything between /* and */
+    ;
+
+LINE_COMMENT
+    : '//' ~[\r\n]* '\r'? '\n'  -> channel(HIDDEN)
+    ;
+
+WS  : [ \r\t\u000C\n]+          -> channel(HIDDEN)
+    ;
+