CODEWITHSUNDEEP
javaparsing
Ka-u Chin
Ka-u Chin

Reputation: 21

How can I take the next character in the scanner of the parser in Java

I don't know how to write the "next source character" code to find the next character of the string.

public class scanner {
    protected char currentChar;
    protected StringBuffer currentSpelling;
    protected byte currentKind;

    private void take (char expectedChar){
        if (currentChar == expectedChar){
            currentSpelling.append(currentChar);
            currentChar = next source character;
        }
    }


    private void takeIt(){
        currentSpelling.append(currentChar);
        currentChar = next source character;
    }

}

Upvotes: 2

Views: 90

Answers (1)

Davide Lorenzo MARINO
Davide Lorenzo MARINO

Reputation: 26946

Probably you need to define your source of chars. Here I passed it to the constructor of Scanner. 

public class Scanner {
    protected char currentChar;
    protected StringBuffer currentSpelling;
    protected byte currentKind;
    private Reader inputStreamReader;

    public Scanner(InputStream inputStream) {
        reader = new InputStreamReader(inputStream);
    }

    private void take (char expectedChar){
        if (currentChar == expectedChar){
            currentSpelling.append(currentChar);
            currentChar = (char) inputStreamReader.read();
        }
    }


    // Note. Probably you need to get the currentChar before append it.
    // So the order of operations should be inverted
    private void takeIt(){
        currentSpelling.append(currentChar);
        currentChar = (char) inputStreamReader.read();
    }

}

To create it you can do something like (or you can replace it to read data from another stream, for example a file):

Scanner myScanner = new Scanner(System.in);

Note: I changed the name of class from scanner to Scanner because it is a good practice to have a class Capitalized.

Upvotes: 1

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