I will be doing further CS coursework later this summer. My submission is a partially completed Lexical Analyzer. I would like to see it completed and used to validate the attached test program. Are y

Study Assignment for Walter W Mayo

public class NCU_PL_Lexer_Driver

public static void main(String [] args) throws java.io.IOException

{

try

{

System.out.println("Beginning lexical analysis of file \"" + args[0] + "\"");

NCU_PL_Lexer lexer = new NCU_PL_Lexer(new java.io.FileInputStream(args[0]));

lexer.NCU_PL_Program();

lexer.ReInit(new java.io.FileInputStream(args[0]));

boolean EOF = false;

while(!EOF)

{

Token token = lexer.token_source.getNextToken();

String tokenKind = NCU_PL_LexerConstants.tokenImage[token.kind];

System.out.print

(

"Token: " + tokenKind +

"\n\tLine: " + token.beginLine +

"\n\tColumn: " + token.beginColumn

);

if(tokenKind.equals("<INTEGER_LITERAL>") || tokenKind.equals("<IDENTIFIER>"))

{

System.out.print("\n\tValue: " + token.image);

}

System.out.println();

EOF = (NCU_PL_LexerConstants.tokenImage[token.kind].equals("<EOF>"));

}

System.out.println("Lexical analysis successfull");

}

catch(ParseException ex)

{

System.out.println("Error parsing input: ");

System.out.println(ex.getMessage());

}

catch(TokenMgrError ex)

{

System.out.println("Error parsing input: ");

System.out.println(ex.getMessage());

}

Page 2 Study assignment for Walter W Mayo

Programming Language Grammar <ncu-pl-program> ::=	“BEGIN NCUPL” <statement>* “END” <EOF>
<statement> ::=	<output-statement> \| <input-statement> \| <variable-declaration> \| <variable-assignment> \| <if-then-statement>
<expression> ::=	“(” <expression> “)” \| <identifier> \| <integer-literal> \| <string-literal> \| <boolean-literal> \| <binary-expression>
<type> ::=	“int” \| “string” \| “bool”
<identifier> ::=	({LETTER}1 \| “_”)+ ({LETTER} \| {DIGIT}2 \| “_”)*3
Literal Values
<integer-literal> ::=	{DIGIT}+
<string-literal> ::=	“"”{ASCII}4* “"”
<boolean-literal> ::=	“true” \| “false”
Expressions
<binary-expression> ::=	<expression> (“+” \| “-“ \| “-“ \| “/” \| “==” \| “<” \| “>”) <expression>
Statements
<variable-declaration> ::=	<type> <identifier> “;”
<input-statement> ::=	“INPUT” <expression> <identifier>5 “;”
<output-statement> ::=	“OUTPUT” <expression> “;”
<variable-assignment> ::=	<identifier> “=” <expression> “;”
<if-then-statement> ::=	“IF” <expression> “THEN” <statement>
Comments
<comment> ::=	“#” {ASCII} “\n”6

TEST PROGRAM

Page 3 Study Assignment for Walter W Mayo

BEGIN NCUPL

# Variables to keep track of years

int yearOfBirth;

int currentYear;

# Variables to keep track of months

int monthOfBirth;

int currentMonth;

# Variables to keep track of days

int dayOfBirth;

int currentDay;

# Get values for birth date

INPUT "What year were you born? " yearOfBirth;

INPUT "What month were you born? " monthOfBirth;

INPUT "What day were you born? " dayOfBirth;

# Get values for current date

INPUT "What year is it now? " currentYear;

INPUT "What month is it now? " currentMonth;

INPUT "What day is it now? " currentDay;

# Declare variables to hold/accumulate days information

int daysSince0000_01_01;

int ageDaysSince0000_01_01;

# Initialize day accumulators to 365 * year + day of month

daysSince0000_01_01 = currentYear * 365;

daysSince0000_01_01 = daysSince0000_01_01 + currentDay;

ageDaysSince0000_01_01 = yearOfBirth * 365;

ageDaysSince0000_01_01 = ageDaysSince0000_01_01 + dayOfBirth;

##### For each month, check to see if the date is

##### greater than that month. If it is, add days

##### equal to the number of days in the month.

### January

IF (monthOfBirth > 1)

THEN ageDaysSince0000_01_01 = ageDaysSince0000_01_01 + 31;