CMSC 430 Project 3
The third project involves modifying the attached interpreter so that it interprets programs for the
complete language.
When the program is run on the command line, the parameters to the function should be supplied
as command line arguments. For example, for the following function header of a program in the
file text.txt:
function main x: integer, y: integer returns character;
One would execute the program as follows:
$ ./compile < test.txt 10 -10
In this case, the parameter x would be initialized to 10 and the parameter y to -10. An example
of a program execution is shown below:
$ ./compile < test.txt 10 -10
1 // Determines the quadrant of a point on the x-y plane
2
3 function main x: integer, y: integer returns character;
4 begin
5 if x > 0 then
6 if y > 0 then
7 ‘1’;
8 elsif y < 0 then
9 ‘4’;
10 else
11 ‘Y’;
12 endif;
13 elsif x < 0 then
14 if y > 0 then
15 ‘3’;
16 elsif y < 0 then
17 ‘2’;
18 else
19 ‘Y’;
20 endif;
21 else
22 if y <> 0 then
23 ‘X’;
24 else
25 ‘O’;
26 endif;
27 endif;
28 end;
Compiled Successfully
Result = 52
After the compilation listing is output, the value of the expression which comprises the body of
the function should be displayed as shown above.
The existing code evaluates some of the arithmetic, relational and logical operators together with
the case statement and decimal integer and real literals only. You are to add the necessary code
to include all of the following:
Hexadecimal integer and character literals that include escape characters
All additional arithmetic operators
All additional relational and logical operators
Both if and fold statements
Functions with multiple variables
Functions with parameters
The fold statement repeatedly applies the specified operation to the list of values, producing one
final value. A left fold associates the operator left to right and a right fold right to left. For
example, the following left fold:
fold left – (3, 2, 1) endfold;
would be evaluated as ((3 – 2) – 1) = 0, but using a right fold:
fold right – (3, 2, 1) endfold;
It would be evaluated as (3 – (2 – 1)) = 2. For operations that are associative, the result would be
the same whether it is as folded to the left or right.
This project requires modification to the bison input file, so that it defines the additional the
necessary computations for the above added features. You will need to add functions to the
library of evaluation functions already provided in values.cc. You must also make some
modifications to the functions already provided.
You are to submit two files.
1. The first is a .zip file that contains all the source code for the project. The .zip file
should contain the flex input file, which should be a .l file, the bison file, which should
be a .y file, all .cc and .h files and a makefile that builds the project.
2. The second is a Word document (PDF or RTF is also acceptable) that contains the
documentation for the project, which should include the following:
a. A discussion of how you approached the project
b. A test plan that includes test cases that you have created indicating what aspects
of the program each one is testing and a screen shot of your compiler run on that
test case
c. A discussion of lessons learned from the project and any improvements that could
be made
