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C Program Formatter written in Java
I am working on a project to implement a Java program that adjusts the formatting of a C program. A few weeks ago we implemented the lexical analyzer to do this and were given a formatter class to work with. For this stage of the project we are now required to implement the if, for, while, and do loops in this formatter class. I feel like I have the correct abstract idea of how to do this, however am having trouble translating this into the code required. I am currently focusing on the IF statements, once I have completed the IF statements I will have a better understanding of completing the other statements.
The tokens that I have implemented are:
And the format class is as follows. I have added nothing more than the function skeleton with comments inside trying to map out the ideas of what I am attempting to do. As well as a few commented-out lines in the statement class.
I am looking for help implementing the IF statement formatter. Do I have the correct “steps” to allow the program to recognize an if statement? I think I can get an idea of how to complete the first few steps by following the example of the switch statement class, however I am unsure after recognizing the initial logical expression where to begin making it read through the rest of the if statement. Any help at all would be appreciated.
The tokens that I have implemented are:
enum Token {NOT_FOUND, UPPER_CASE_IDENTIFIER, CONSTANT, COMMENT,
COMPILER_DIRECTIVE, ASSIGNMENT_OPERATOR,
PRE_OR_POST_UNARY_OPERATOR, STRUCTURE_OPERATOR,
UNARY_OR_BINARY_OPERATOR,UNARY_OPERATOR, BINARY_OPERATOR,
TERNARY_OPERATOR, COLON, LEFT_PARENTHESIS, RIGHT_PARENTHESIS,
LEFT_BRACKET, RIGHT_BRACKET, LEFT_BRACE, RIGHT_BRACE, SEMICOLON,
COMMA, STRING, SC_SPECIFIER, BREAK, CASE, TYPE_SPECIFIER,
CONTINUE, DEFAULT, DO, ELSE, FOR, GOTO, IF, RETURN, SIZEOF,
STATUS, STRUCT, SWITCH, UNION, WHILE, IDENTIFIER, FIRST, NONE,
END_OF_FILE}And the format class is as follows. I have added nothing more than the function skeleton with comments inside trying to map out the ideas of what I am attempting to do. As well as a few commented-out lines in the statement class.
class Format
{
private Lexer lexer;
private Output output;
private Token token;
// The constructor establishes the input lexer and the output
// private data members.
public Format(Lexer lexer, Output output)
{
this.lexer = lexer;
this.output = output;
}
// file is the only public method. External
// declarations are formatted until a function is found, at
// which time functionBody is called to format it.
public void file()
{
token = lexer.getNextToken();
while (token != Token.END_OF_FILE)
if (externalDeclaration())
functionBody();
}
// functionBody formats the declarations and statements in a
// function body.
private void functionBody()
{
output.endLine(true);
while (token == Token.TYPE_SPECIFIER ||
token == Token.SC_SPECIFIER ||
token == Token.STRUCT || token == Token.UNION ||
token == Token.UPPER_CASE_IDENTIFIER)
parameterDeclaration();
output.indent();
output.endLine(false);
output.skipLine();
compoundStatement();
output.unindent();
output.endLine(false);
output.endPage();
}
// compoundStatement formats a multiple statement block
private void compoundStatement()
{
int noOfDeclarations= 0;
token = lexer.getNextToken();
output.endLine(false);
while (token == Token.TYPE_SPECIFIER ||
token == Token.SC_SPECIFIER ||
token == Token.STRUCT || token == Token.UNION ||
token == Token.UPPER_CASE_IDENTIFIER)
{
declaration();
noOfDeclarations++;
}
if (noOfDeclarations > 0)
output.skipLine();
while (token != Token.RIGHT_BRACE)
statement();
token = lexer.getNextToken();
output.endLine(false);
}
// statement determines the type of statement and calls the
// appropriate function to format it.
private void statement()
{
if (token == Token.IDENTIFIER)
if ((token = lexer.getNextToken()) == Token.COLON)
token = lexer.getNextToken();
else
{
token = Token.IDENTIFIER;
lexer.putLastToken();
}
switch (token)
{
case LEFT_BRACE:
compoundStatement();
break;
case SWITCH:
switchStatement();
break;
case BREAK:
case CONTINUE:
verifyNextToken(Token.SEMICOLON);
output.endLine(false);
break;
case RETURN:
if ((token = lexer.getNextToken()) != Token.SEMICOLON)
{
expression(Token.SEMICOLON);
token = lexer.getNextToken();
}
else
token = lexer.getNextToken();
output.endLine(false);
break;
case GOTO:
verifyNextToken(Token.IDENTIFIER);
verifyNextToken(Token.SEMICOLON);
output.endLine(false);
break;
// insert IF statement case
/*case IF:
ifStatement();
break;*/
default:
expression(Token.SEMICOLON);
token = lexer.getNextToken();
output.endLine(false);
}
}
// switchStatement formats a switch statement.
private void switchStatement()
{
verifyNextToken(Token.LEFT_PARENTHESIS);
expression(Token.RIGHT_PARENTHESIS);
token = lexer.getNextToken();
output.endLine(false);
output.indent();
verifyCurrentToken(Token.LEFT_BRACE);
output.endLine(false);
while (token == Token.CASE || token == Token.DEFAULT)
{
if (token == Token.CASE)
{
expression(Token.COLON);
lexer.adjustSpacing(Lexer.SUPPRESS_LEADING_SPACE);
token = lexer.getNextToken();
output.endLine(false);
output.indent();
while (token != Token.CASE && token !=
Token.DEFAULT && token != Token.RIGHT_BRACE)
statement();
output.unindent();
}
else
{
expression(Token.COLON);
lexer.adjustSpacing(Lexer.SUPPRESS_LEADING_SPACE);
token = lexer.getNextToken();
output.endLine(false);
output.indent();
while (token != Token.CASE && token != Token.DEFAULT &&
token != Token.RIGHT_BRACE)
statement();
output.unindent();
}
}
verifyCurrentToken(Token.RIGHT_BRACE);
output.endLine(false);
output.unindent();
}
// if statement
private void ifStatement()
{
// the next token should be a left parenthesis
// followed by an expression
// followed by a right parenthesis token
// followed by a statement
// possibly followed by an 'else' token
// followed by a statement
}
// for statement
private void forStatement()
{
// the next token should be a left parenthesis
// followed by an expression
// followed by a semicolon token
// followed by an expression
// followed by a semicolon token
// followed by an expression
// followed by a right parenthesis token
// followed by a statement
}
// while statement
private void whileStatement()
{
// next token is a left parenthesis
// followed by an expression
// followed by a right parenthesis token
// followed by a statement
}
// do statement
private void doStatement()
{
// next token is a statement
// followed by a while token
// followed by a left parenthesis token
// followed by an expression
// followed by a right parenthesis token
}
// externalDeclarations formats external declarations such as
// global variables and function prototypes. It returns if
// it encounters a function heading.
private boolean externalDeclaration()
{
int braceCount = 0;
boolean indentAtSemicolon = false;
Token lastToken = Token.NOT_FOUND;
while ((braceCount > 0) || (token != Token.SEMICOLON))
{
lexer.checkDeclarationSpacing(token);
if (token == Token.LEFT_BRACE)
{
output.endLine(false);
output.indent();
lastToken = token;
token = lexer.getNextToken();
output.endLine(false);
braceCount++;
}
else if (token == Token.RIGHT_BRACE)
{
lastToken = token;
token = lexer.getNextToken();
indentAtSemicolon = true;
braceCount--;
}
else if (token == Token.LEFT_PARENTHESIS)
{
lastToken = token;
token = lexer.getNextToken();
}
else if (token == Token.RIGHT_PARENTHESIS)
{
lastToken = token;
token = lexer.getNextToken();
if (token != Token.SEMICOLON)
return true;
}
else if (token == Token.ASSIGNMENT_OPERATOR)
while (token != Token.SEMICOLON)
{
lastToken = token;
token = lexer.getNextToken();
lexer.checkExpressionSpacing(token, lastToken);
}
else if (token == Token.SEMICOLON)
{
lastToken = token;
token = lexer.getNextToken();
if (braceCount > 0)
output.endLine(false);
if (indentAtSemicolon)
{
output.indent();
indentAtSemicolon = false;
}
}
else
{
lastToken = token;
token = lexer.getNextToken();
}
}
token = lexer.getNextToken();
output.endLine(false);
if (indentAtSemicolon)
output.indent();
return false;
}
// parameterDeclaration formats parameter declarations.
private void parameterDeclaration()
{
int braceCount = 0;
while ((braceCount > 0) || (token != Token.SEMICOLON))
{
lexer.checkDeclarationSpacing(token);
if (token == Token.LEFT_BRACE)
{
output.endLine(false);
output.indent();
token = lexer.getNextToken();
output.endLine(false);
braceCount++;
}
else if (token == Token.RIGHT_BRACE)
{
token = lexer.getNextToken();
output.indent();
braceCount--;
}
else if ((braceCount > 0 ) && (token == Token.SEMICOLON))
{
token = lexer.getNextToken();
output.endLine(false);
}
else
token = lexer.getNextToken();
}
token = lexer.getNextToken();
output.endLine(false);
}
// declaration formats local declarations.
private void declaration()
{
int braceCount = 0;
boolean indentAtSemicolon = false;
while ((braceCount > 0) || (token != Token.SEMICOLON))
{
lexer.checkDeclarationSpacing(token);
if (token == Token.LEFT_BRACE)
{
output.endLine(false);
output.indent();
token = lexer.getNextToken();
output.endLine(false);
braceCount++;
}
else if (token == Token.RIGHT_BRACE)
{
token = lexer.getNextToken();
indentAtSemicolon = true;
braceCount--;
}
else if (token == Token.SEMICOLON)
{
token = lexer.getNextToken();
if (braceCount > 0)
output.endLine(false);
if (indentAtSemicolon)
{
output.indent();
indentAtSemicolon = false;
}
}
else if (token == Token.ASSIGNMENT_OPERATOR)
expression(Token.SEMICOLON);
else
token = lexer.getNextToken();
}
token = lexer.getNextToken();
output.endLine(false);
if (indentAtSemicolon)
output.indent();
}
// expression formats an expression. The delimiting token must
// be provided.
private void expression(Token terminator)
{
Token lastToken;
lastToken = Token.NOT_FOUND;
while (token != terminator)
{
lexer.checkExpressionSpacing(token, lastToken);
if (token == Token.LEFT_PARENTHESIS)
{
if (lastToken == Token.IDENTIFIER ||
lastToken == Token.UPPER_CASE_IDENTIFIER)
lexer.adjustSpacing(Lexer.SUPPRESS_LEADING_SPACE);
token = lexer.getNextToken();
expression(Token.RIGHT_PARENTHESIS);
}
lastToken = token;
token = lexer.getNextToken();
}
}
// Gets the next token and then verifies that the supplied token is
// the required token.
private void verifyNextToken(Token requiredToken)
{
token = lexer.getNextToken();
verifyCurrentToken(requiredToken);
}
// Verifies that the supplied token is the current token.
// Displays an error message if it is not.
private void verifyCurrentToken(Token requiredToken)
{
if (token != requiredToken)
output.outputError("MISSING " + requiredToken.name());
else
token = lexer.getNextToken();
}
}I am looking for help implementing the IF statement formatter. Do I have the correct “steps” to allow the program to recognize an if statement? I think I can get an idea of how to complete the first few steps by following the example of the switch statement class, however I am unsure after recognizing the initial logical expression where to begin making it read through the rest of the if statement. Any help at all would be appreciated.
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