muali / swd-interpreter

Parser and interpreter of a simple mathcad-like language

swd-interpreter

In this task you develop a small parser and interpreter of a simple mathcad-like language Based on existing codebase you will:

1. (Done) Support parsing and evaluation of simple arithmetic expressions

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   (2 + 1) + (12)

ru.spbau.interpreter.Statements.Expressions.Expression grammar is defined the following way:

    Expr -> Const | (Expr) | Expr + Expr
    Const -> \d+

2. Support variables

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    var x = 234 + 45
    var a = x + 12

Updated grammar:

    Expr -> Const | Var | (Expr) | Expr + Expr
    Var -> \w+
    Assign -> var Var = Expr 
    Stmt = Expr | Assign

3. Support scoping

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    var x = 2 + 6 // x == 8 
        var y = x + 8 // new scope, y == 16
        var x = 0 // local scoped x
        var q = x + 7 // q == 7
    var z = x + 1 //z == 9

While interpreting, program should print every var value daclaration

4. Develop simple API to allow program static analysis

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Examples (implement any 1):

• Calculate number of vars in program
• Calculate numer of addition operator usages
• Calculate number of parenthis in program
• ...