CODEWITHSUNDEEP
mathtypesexpressionantlr
user11113981
user11113981

Reputation:

antlr same type arithmetic expression

Trying to write a antlr grammar that parse the arithmetic expression for only same typed variable. If it is not a same type as left or right side, it should not be parse. This is what I have; 

stat
    :   Left = VARIABLE Op = ASSIGMENT Right = expr     # Assigment
    ;

expr
    :   '('   Exp = expr ')'                            # Parens
    |   MINUS Exp = expr                                # UnaryMinus
    |   Left = expr Op = (TIMES | DIV)  Right = expr    # MulDiv
    |   Left = expr Op = (PLUS  | MINUS) Right = expr   # AddSub
    |   (VARIABLE | CONSTANT)                           # Element
    ;

ASSIGMENT   :   '=' ;
PLUS        :   '+' ;
MINUS       :   '-' ;
TIMES       :   '*' ;
DIV         :   '/' ;
LPAREN      :   '(' ;
RPAREN      :   ')' ;

I don't want anything like x = 5 + 'f' or x = c - 5, (if c is variable that is not integer)

Upvotes: 1

Views: 161

Answers (1)

Pavel Smirnov
Pavel Smirnov

Reputation: 4799

It's called Semantic analysis.

When parsing is done you have to walk through the generated AST and check correctness of each expression and variable.

Upvotes: 1

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