Tema 150119

Pagina 1

Formal Languages and Compilers Proff. Breveglieri, Crespi Reghizzi, Morzenti Written exam1: laboratory question 15/01/2019 SURNAME: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . NAME: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Student ID:. . . . . . . . . . . . . . . . Course: ◦ Laurea Specialistica ◦ V. O. ◦ Laurea Triennale ◦ Other: . . . Instructor: ◦ Prof. Breveglieri ◦ Prof Morzenti The laboratory question must be answered taking into account the implementation of the Acse compiler given with the exam text. Modify the specification of the lexical analyser ( flex input) and the syntactic analyser (bison input) and any other source file required to extend the Lance language with the scalar product operator. The operator, indicated by the @ symbol, performs the scalar product between two conformant integer arrays. The precedence of the scalar product operator is higher than any other operator. An attempt to employ it to multiply scalars or non conformant arrays must result in a compile-time error. The following code snippet provides an example of operator use. int u[3],v[3],a; v[0]=1; v[1]=2; v[2]=-1; u[0]=8; u[1]=1; u[2]=2; a = v@v + 1; /* a == 7 after this statement */ if (u@v) { write(1); /* this statement is executed */ } else { write(0); } 1Time 60’. Textbooks and notes can be used. Pencil writing is allowed. Write your name on any additional sheet. 1 1. Define the tokens (and the related declarations in Acse.lex and Acse.y). (2 points) 2. Define the syntactic rules or the modifications required to the existing ones. (4 points) 3. Define the semantic actions needed to implement the required functionality. (18…