Semantic Analyzer

A semantic analyzer for a subset of the Java programming language.

From Wikipedia: Semantic analysis, also context sensitive analysis, is a process in compiler construction, usually after parsing, to gather necessary semantic information from the source code. It usually includes type checking, or makes sure a variable is declared before use which is impossible to describe in Extended Backus–Naur Form and thus not easily detected during parsing.

Prerequisites:

The application was built using Java so you should have the JDK (Java Development Kit) installed on your machine to be able to run it.

Features:

1. Lexical analysis.
2. Syntax analysis (Parsing).
3. Semantic analysis.

Usage:

1. Download or clone this repository to your machine.
2. Compile and run any Tester class (Testlexer, TestParser, or TestSemantic) with a command-line argument refers to a test file path.

javac Testlexer.java
java Testlexer test_file_path

Or

javac TestParser.java
java TestParser test_file_path

Or

javac TestSemantic.java
java TestSemantic test_file_path

Note: You can find some test files in the tests folder.

Tokens (Lexemes) regular expression:

• Letter: [a-zA-Z]
• Digit: [0-9]
• Identifier: letter (letter | digit)*
• Integer: digit+
• Float: Integer . Integer
• Boolean: true | false
• Char: ‘ASCII Char‘
• Literal: Integer | Boolean | Float | Char
• ReservedWords: main | int | float | char| boolean | if | else | true | false | false | while
• AssignmentOperator: =
• EqualOperator: ==
• NotEqualOperator: !=
• RelationalOperator: <|<=|>|>=
• ArithmeticOperator: + | - | * | / | %
• UnaryOperator: - | !
• BooleanOperator: && | ||
• Operator: EqualOperator| NotEqualOperator | RelationalOperator | ArithmeticOperator| UnaryOperator | BooleanOperator | AssignmentOperator
• RightBrace: }
• LeftBrace: {
• RightParenthese: )
• LeftParenthese: (
• RightBracket: ]
• LeftBracket: [
• Semicolon: ;
• Comma: ,

Grammer BNF notation:

• Program ::= int main () { Declarations Statements }
• Declarations ::= { Declaration }
• Declaration ::= Type Identifier [ [ Integer ] ] { , Identifier [ [ Integer ] ] }
• Type ::= int | bool | float | char
• Statements ::= { Statement }
• Statement ::= ; | Block | Assignment | IfStatement | WhileStatement
• Block ::= { Statements }
• Assignment ::= Identifier [ [ Expression ] ] = Expression;
• IfStatement ::= if ( Expression ) Statement [ else Statement ]
• WhileStatement ::= while ( Expression ) Statement
• Expression ::= Conjunction { || Conjunction }
• Conjunction ::= Equality { && Equality }
• Equality ::= Relation [ EquOp Relation ]
• EquOp ::= == | !=
• Relation ::= Addition [ RelOp Addition]
• RelOp ::= < | <= | > | >=
• Addition ::= Term { AddOp Term }
• AddOp ::= + | -
• Term ::= Factor { MulOp Factor }
• MulOp ::= * | / | %
• Factor ::= [ UnaryOp ] Primary
• UnaryOP ::= - | !
• Primary ::= Identifier [ [Expression] ] | Literal | ( Expression ) | Type ( Expression)
• Identifier ::= Letter { Letter | Digit }
• Letter ::= a | b | … | z | A | B | … | Z
• Digit ::= 0 | 1 | … | 9
• Literal ::= Integer | Boolean | Float | Char
• Integer ::= Digit { Digit }
• Boolean ::= true | false
• Float ::= Integer.Integer
• Char ::= 'ASCIIChar'

Semantic Rules:

• Rule one:

  • All referenced variables must be declared.
  • All declared variables must have unique names.

• Rule two:

  An Assignment is valid if:
  1. Its target Variable is declared.
  2. Its source Expression is valid.
  3. If the target Variable is float, then the type of the source Expression must be either float or int.
  4. Otherwise if the target Variable is int, then the type of the source Expression must be either int or char.
  5. Otherwise the target Variable must have the same type as the source Expression.

License:

This software is licensed under the Modified BSD License.