[SOLVED] CMSC 430 Project 2

CMSC 430 Project 2
The second project involves modifying the syntactic analyzer for the attached compiler by
adding to the existing grammar. The full grammar of the language is shown below. The
highlighted portions of the grammar show what you must either modify or add to the existing
grammar.
function:
function_header {variable} body
function_header:
FUNCTION IDENTIFIER [parameters] RETURNS type ;
variable:
IDENTIFIER : type IS statement ; |
IDENTIFIER : LIST OF type IS list ;
list:
( expression {, expression} )
parameters:
parameter {, parameter}
parameter:
IDENTIFIER : type
type:
INTEGER | REAL | CHARACTER
body:
BEGIN statement END ;
statement:
expression ; |
WHEN condition , expression : expression ; |
SWITCH expression IS {case} OTHERS ARROW statement ENDSWITCH ; |
IF condition THEN statement {ELSIF condition THEN statement}
ELSE statement ENDIF ; |
FOLD direction operator list_choice ENDFOLD ;
case:
CASE INT_LITERAL ARROW statement
direction:
LEFT | RIGHT
operator:
ADDOP | MULOP
list_choice:
list |
IDENTIFIER
condition:
expression RELOP expression |
condition logical_operator condition |
( condition ) |
NOTOP condition
logical_operator:
ANDOP | OROP
expression:
( expression ) |
expression arithmetic_operator expression |
NEGOP expression |
INT_LITERAL | REAL_LITERAL | CHAR_LITERAL |
IDENTIFIER ( expression ) |
IDENTIFIER

arithmetic_operator: ADDOP | MULOP | MODOP | EXPOP
In the above grammar, the red symbols are nonterminals, the blue symbols are terminals and the
black punctuation are EBNF metasymbols. The braces denote repetition 0 or more times and the
brackets denote optional.
You must rewrite the grammar to eliminate the EBNF brace and bracket metasymbols and to
incorporate the significance of parentheses, operator precedence and associativity for all
operators. The precedence and associativity rules are as follows:
 Among binary arithmetic operators the exponentiation operator has highest precedence
followed by the multiplying operators and then the adding operators. But the unary
negation operator ~ has higher precedence that all of the binary operators.
 All relational operators have the same precedence.
 Among the binary logical operators, & has higher precedence than |. But the unary logical
operator ! has higher precedence than either of the binary logical operators.
 All binary operators except the exponentiation operator are left associative.
The directives to specify precedence and associativity, such as %prec and %left, may not be
used.
Your parser should be able to correctly parse any syntactically correct program without any
problem.
You must modify the syntactic analyzer to detect and recover from additional syntax errors using
the semicolon as the synchronization token. To accomplish detecting additional errors an error
production must be added to the function body, to the variable declaration and to the when
clause.
Your bison input file should not produce any shift/reduce or reduce/reduce errors. Eliminating
them can be difficult so the best strategy is not introduce any. That is best achieved by making
small incremental additions to the grammar and ensuring that no addition introduces any such
errors.
An example of compilation listing output containing syntax errors is shown below:
1 — Multiple errors
2
3 function main a integer returns real;
Syntax Error, Unexpected INTEGER, expecting ‘:’
4 b: integer is * 2;
Syntax Error, Unexpected MULOP
5 c: real is 6.0;
6 begin
7 if a > c then
8 b + / .4;
Syntax Error, Unexpected MULOP
9 else
10 case b is
11 when => 2;
Syntax Error, Unexpected ARROW, expecting INT_LITERAL
12 when 2 => c;
13 endcase;
Syntax Error, Unexpected ENDCASE, expecting OTHERS or WHEN
14 endif;
15 end;
Lexical Errors 0
Syntax Errors 5
Semantic Errors 0
You are to submit two files.
 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.
 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