Reference no: EM132690724

CMSC 430 Introduction to Compilers - University of Maryland

Project
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

parameters:
parameter {, parameter}

parameter:
IDENTIFIER : type

type:
INTEGER | REAL | BOOLEAN

body:
BEGIN statement END ;

statement: expression ; |
REDUCE operator {statement} ENDREDUCE ; |
IF expression THEN statement ELSE statement ENDIF ; |
CASE expression IS {case} OTHERS ARROW statement ; ENDCASE ;

operator:
ADDOP | MULOP

case:
WHEN INT_LITERAL ARROW statement

expression:
( expression ) |
expression binary_operator expression |
|

INT_LITERAL | IDENTIFIER

| BOOL_LITERAL |

binary_operator: ADDOP | MULOP | REMOP | EXPOP | RELOP | ANDOP | OROP

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. Among arithmetic operators the exponentiation operator has highest precedence following by the multiplying operators and then the adding operators. All relational operators have the same precedence. Among the binary logical operators, and has higher precedence than or. Of the categories of operators, the unary logical operator has highest precedence, the arithmetic operators have next highest precedence, followed by the relational operators and finally the binary logical operators. All 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 header and another to the variable declaration.

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.

Attachment:- Introduction to Compilers.rar