In class we saw how to evaluate an expression given a map from identifiers to their...

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In class we saw how to evaluate an expression given a map from identifiers to their values. def evalExpr (e: Expr, env: Hap[String, Double]): Double = ... In this assignment, you are asked to handle assignment statement. The Idea here is that the assignment statement takes an environment and modifies it. def evalstatement(s: Statement, env: Rap[String, Double]): Hap[String, Double] =... As an example consider the map env Hap("x"-> 20, "y" -> 35) The assignment statement z:-x+y Assignment("z", Plus (var("x"), Var("Y"))) Should return a map Hap("x"-> 20, "y" -> 35, "2" -> 55) The strategy should be as follows: (a) evaluate the expression in the RHS of the assignment statement, (D) add the entry that maps the declared variable to the new value and (c) return this map. https://docs.scala-lang.org/overviews/collections-2.13/maps.html In []: def evalExpr(e: Expr, env: Rap[String, Double]): Double = { def binFun(el: Expir, e2: Expr, op: (Double, Double) => Double): Double = { val vi evalExpr(el, env) } e match { case Plus (el, e2) => binFun(el, ez, _ + _ ), case Minus(el, e2) => binFun(el, e2, _) } val v2 = evalExpr(e2, env) op (v1, v2) } } case Star (el, e2) => binFun(el, e2, __) case Ver(v) => { if (env.contains(v)){ } else { throw new IllegalArgumentException(s"$v undefined variable.") } env(v) } case Const(f) => f def evalstatement(s: Statement, env: Rap[String, Double]): Nap[String, Double] =smatch { case Assignment(varliame, rhsExpr) => { // YOUR CODE HERE 222 In []: //BEGIN TEST def testlap (m1: Hap[String, Double], varname: String, testval: Double) = { m1.contains (varnamne) && m1(varname) == testval } val ml = Hap[String, Double]() val v1 = Assignment(x", Const(2.0)) val m2 = evalstatement(v1, m1) assert (testlap (m2, "x", 2.0), "TEST 1 PASSED!") passed (10) //END TEST val v2 = Assignment("y", Plus (Var("x"). Const(4.0))) val m3 = evelstatenment(v2, m2) assert (testisp(m3, "x", 2.0), "TEST 2.1 PASSED!") assert(testisp(m3, "y", 6.0), "TEST 2.2 PASSED!") val v3 = Assignment("z", Star(var(""), Var("x"))) val m4 = evalstatement(v3, m3) assert (testhop (n4, "x", 2.0), "TEST 3.1 PASSED!") assert(test ap(m4, "y", 6.0), "TEST 3.2 PASSED!") assert (testop(n4, "z", 12.0), "TEST 3.3 PASSED!") In class we saw how to evaluate an expression given a map from identifiers to their values. def evalExpr (e: Expr, env: Hap[String, Double]): Double = ... In this assignment, you are asked to handle assignment statement. The Idea here is that the assignment statement takes an environment and modifies it. def evalstatement(s: Statement, env: Rap[String, Double]): Hap[String, Double] =... As an example consider the map env Hap("x"-> 20, "y" -> 35) The assignment statement z:-x+y Assignment("z", Plus (var("x"), Var("Y"))) Should return a map Hap("x"-> 20, "y" -> 35, "2" -> 55) The strategy should be as follows: (a) evaluate the expression in the RHS of the assignment statement, (D) add the entry that maps the declared variable to the new value and (c) return this map. https://docs.scala-lang.org/overviews/collections-2.13/maps.html In []: def evalExpr(e: Expr, env: Rap[String, Double]): Double = { def binFun(el: Expir, e2: Expr, op: (Double, Double) => Double): Double = { val vi evalExpr(el, env) } e match { case Plus (el, e2) => binFun(el, ez, _ + _ ), case Minus(el, e2) => binFun(el, e2, _) } val v2 = evalExpr(e2, env) op (v1, v2) } } case Star (el, e2) => binFun(el, e2, __) case Ver(v) => { if (env.contains(v)){ } else { throw new IllegalArgumentException(s"$v undefined variable.") } env(v) } case Const(f) => f def evalstatement(s: Statement, env: Rap[String, Double]): Nap[String, Double] =smatch { case Assignment(varliame, rhsExpr) => { // YOUR CODE HERE 222 In []: //BEGIN TEST def testlap (m1: Hap[String, Double], varname: String, testval: Double) = { m1.contains (varnamne) && m1(varname) == testval } val ml = Hap[String, Double]() val v1 = Assignment(x", Const(2.0)) val m2 = evalstatement(v1, m1) assert (testlap (m2, "x", 2.0), "TEST 1 PASSED!") passed (10) //END TEST val v2 = Assignment("y", Plus (Var("x"). Const(4.0))) val m3 = evelstatenment(v2, m2) assert (testisp(m3, "x", 2.0), "TEST 2.1 PASSED!") assert(testisp(m3, "y", 6.0), "TEST 2.2 PASSED!") val v3 = Assignment("z", Star(var(""), Var("x"))) val m4 = evalstatement(v3, m3) assert (testhop (n4, "x", 2.0), "TEST 3.1 PASSED!") assert(test ap(m4, "y", 6.0), "TEST 3.2 PASSED!") assert (testop(n4, "z", 12.0), "TEST 3.3 PASSED!")

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Heres the implementation for the evalstatement function scala def evalstatemen... View the full answer