/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

//
// $Rev$ $Id$
//

grammar CommandLine;

options {
    language=Java;
    output=AST;
    ASTLabelType=CommonTree;
    // k=2;
    // backtrack=true;
    // memoize=true;
}

@header {
package org.apache.geronimo.gshell.parser;
}

@lexer::header {
package org.apache.geronimo.gshell.parser;
}

//
// FIXME: Still need to work out whitespace muck, this isn't always happy... :-(
//

compilationUnit
    :  ( expression ( ';' | NewLine | EOF ) )*
    ;

expression
    : ( WhiteSpace* argument WhiteSpace* )+
    ;

argument
    : literal
    ;

literal
    : OpaqueStringLiteral
    | StringLiteral
    | PlainStringLiteral
    ;	

//
// Lexer
//

//
// FIXME: Need to figure out how to handle \r\n too
//

NewLine
    : ( '\n' )
    ;

WhiteSpace
    : ( ' ' | '\t' | '\r' ) // { $channel=HIDDEN; }
    ;

PlainStringLiteral
    : ( ~( ';' | '\'' | '"' | WhiteSpace ) )+
    ;

OpaqueStringLiteral
    : '\'' ( EscapeSequence | ~( '\\' | '\'' ) )* '\''
    ;

//
// TODO: Figure out how to parse out ${foo.bar} and "$foo bar", for variable expansion
//

StringLiteral
    :  	'"' ( EscapeSequence | ~( '\\' | '"' ) )* '"'
    ;

fragment
EscapeSequence
    :   '\\' ('b'|'t'|'n'|'f'|'r'|'\"'|'\''|'\\')
    ;