javajflexcup

JFlex with CUP compile errors

I am trying to run an example provided by CUP: Parsing directly to XML.

I stored the 'Minijava Grammar' in a file named minijava.cup and the scanner into a file named xml.flex. I ran JFlex to obtain Lexer.java from the xml.flex file. After that I obtained Parser.java and sym.java after running the command specified on the CUP example:

java -jar java-cup-11b.jar -locations -interface -parser Parser -xmlactions minijava.cup

My directory looks like this:

input.xml
java-cup-11b.jar
java-cup-11b-runtime.jar
jflex-1.6.1.jar
Lexer.java
minyjava.cup
Parser.java
sym.java
xml.flex

I am trying to compile the Lexer.java file by using the following command:

javac -cp java-cup-11b-runtime.jar Lexer.java

but I get 47 errrors in the format "..cannot find symbol...". The first ones specify that classes sym and minijava.Constants can't be found.

Lexer.java:17: error: cannot find symbol

public class Lexer implements java_cup.runtime.Scanner, sym, minijava.Constants{

^ symbol: class sym

Lexer.java:17: error: package minijava does not exist

public class Lexer implements java_cup.runtime.Scanner, sym, minijava.Constants {

^ Lexer.java:679: error: cannot find symbol

{return symbolFactory.newSymbol("EOF", EOF, new Location(yyline+ 1,yycolumn+1,yychar), new Location(yyline+1,yycolumn+1,yychar+1));

I do not understand why the sym.java file is not visible to Lexer or where to get the minijava.Constants file.

Solution

  • You are missing the current directory (where your sources are) in the classpath. It is not included by default, but if you put . in the %CLASSPATH% (or $CLASSPATH for unices) environment variable.

    Try to change the -cp setting to add the current directory ..

    javac -cp .;java-cup-11b-runtime.jar Lexer.java

    If you are on a GNU/Linux, OS X or any UNIX-like system, it would be

    javac -cp .:java-cup-11b-runtime.jar Lexer.java

    In the same way, add the current directory to the -cp parameter when running with java command.