Class LexicalAnalyzer

java.lang.Object

LexicalAnalyzer

public class LexicalAnalyzer
extends java.lang.Object

Lexical analyzer implementing the DFA.

This analyzes the lexical content of the code entered by the user. It also feed the table of symbols with identifiers, images and number of line.

Author:

Quentin Delhaye

See Also:

SymbolsTable

Field Summary

Fields

Modifier and Type	Field and Description
private java.util.List<java.lang.String>	keywords List of all the possible keywords.
private java.lang.String[]	label Array containing an identifier and the line number on which it occurred.
private SymbolsTable	symTab Table of symbols.
private java.util.List<java.lang.String>	units List of all the possible lexical units corresponding to the equivalent keyword.
private java.lang.String[]	variable Array containing an identifier and its corresponding image.

Constructor Summary

Constructors

Constructor and Description
LexicalAnalyzer() Constructor

Method Summary

Methods

Modifier and Type	Method and Description
private boolean	isComment(java.lang.String input, boolean newLine) Checks if the input String is a comment.
private boolean	isIdentifier(java.lang.String input) Checks if the input String is an identifier.
private boolean	isImage(java.lang.String input) Checks if the input String is an image.
private boolean	isInteger(java.lang.String input) Checks if the input String is an integer.
private boolean	isReal(java.lang.String input) Checks if the input String is a real number.
private boolean	isString(java.lang.String input) Checks if the input String is a string.
java.lang.String[]	nextToken(java.lang.String input, boolean newLine, int lineNum) Analyzes the String it is feed with.
void	printSymbolsTable() Ask the table of symbols to the SymbolsTable object and print it on the standard output.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

keywords

private java.util.List<java.lang.String> keywords

List of all the possible keywords.

units

private java.util.List<java.lang.String> units

List of all the possible lexical units corresponding to the equivalent keyword.

See Also:

keywords

variable

private java.lang.String[] variable

Array containing an identifier and its corresponding image. Used to feed the table of symbols.

See Also:

SymbolsTable.addVariable(java.lang.String[])

label

private java.lang.String[] label

Array containing an identifier and the line number on which it occurred. Used to feed the table of symbols.

See Also:

SymbolsTable.addLabel(java.lang.String[])

symTab

private SymbolsTable symTab

Table of symbols.

See Also:

SymbolsTable

Constructor Detail

LexicalAnalyzer

public LexicalAnalyzer()

Constructor

Initializes the keywords and lexical units ArrayLists. Creates the table of symbols.

Method Detail

isIdentifier

private boolean isIdentifier(java.lang.String input)

Checks if the input String is an identifier.

Parameters:

input - Candidate to the identifier status.

Returns:

True if the input matches the regex.

isImage

private boolean isImage(java.lang.String input)

Checks if the input String is an image.

Parameters:

input - Candidate to the image status.

Returns:

True if the input matches the regex.

isInteger

private boolean isInteger(java.lang.String input)

Checks if the input String is an integer.

Parameters:

input - Candidate to the integer status.

Returns:

True if the input matches the regex.

isReal

private boolean isReal(java.lang.String input)

Checks if the input String is a real number.

Parameters:

input - Candidate to the real status.

Returns:

True if the input matches the regex.

isString

private boolean isString(java.lang.String input)

Checks if the input String is a string.

Parameters:

input - Candidate to the string status.

Returns:

True if the input matches the regex.

isComment

private boolean isComment(java.lang.String input,
                boolean newLine)

Checks if the input String is a comment.

Parameters:

input - Candidate to the comment status.

Returns:

True if the input matches the regex.

nextToken

public java.lang.String[] nextToken(java.lang.String input,
                           boolean newLine,
                           int lineNum)

Analyzes the String it is feed with.

It begins by checking either the input is a comment or not. If not, it splits it and begins the analysis. As soon as a token is recognized, the method gives it back to the caller along the corresponding lexical unit.

It will also feed the table of symbols with various couple of identifier/image or identifier/line number.

Parameters:

input - String to analyze.

newLine - Boolean telling if the input String is the beginning of a new line or not. Useful for the isComment() method.

lineNum - Line of the current String being analyzed. Useful for the table of symbols.

Returns:

Array containing the result of the analysis:

• [0]: token.
• [1]: lexical unit.

See Also:

SymbolsTable.addLabel(java.lang.String[]), SymbolsTable.addVariable(java.lang.String[])

printSymbolsTable

public void printSymbolsTable()

Ask the table of symbols to the SymbolsTable object and print it on the standard output.

See Also:

SymbolsTable.toString()