/*******************************************************************************
* Copyright (c) 2009, 2010 Cloudsmith Inc. and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* Cloudsmith Inc. - initial API and implementation
*******************************************************************************/
package org.eclipse.equinox.internal.p2.metadata.expression.parser;
import java.util.*;
import org.eclipse.equinox.internal.p2.metadata.expression.Variable;
import org.eclipse.equinox.p2.metadata.expression.IExpression;
import org.eclipse.equinox.p2.metadata.expression.IExpressionFactory;
public class QLParser extends ExpressionParser {
private static final long serialVersionUID = 882034383978853143L;
private static final int TOKEN_ANY = 42;
private static final int TOKEN_LATEST = 70;
private static final int TOKEN_LIMIT = 71;
private static final int TOKEN_FIRST = 72;
private static final int TOKEN_FLATTEN = 73;
private static final int TOKEN_UNIQUE = 74;
private static final int TOKEN_SELECT = 75;
private static final int TOKEN_COLLECT = 76;
private static final int TOKEN_TRAVERSE = 77;
private static final int TOKEN_INTERSECT = 78;
private static final int TOKEN_UNION = 79;
private static final Map<String, Integer> qlKeywords;
static {
qlKeywords = new HashMap<String, Integer>();
qlKeywords.putAll(keywords);
qlKeywords.put(KEYWORD_COLLECT, new Integer(TOKEN_COLLECT));
qlKeywords.put(KEYWORD_FALSE, new Integer(TOKEN_FALSE));
qlKeywords.put(KEYWORD_FIRST, new Integer(TOKEN_FIRST));
qlKeywords.put(KEYWORD_FLATTEN, new Integer(TOKEN_FLATTEN));
qlKeywords.put(KEYWORD_LATEST, new Integer(TOKEN_LATEST));
qlKeywords.put(KEYWORD_LIMIT, new Integer(TOKEN_LIMIT));
qlKeywords.put(KEYWORD_NULL, new Integer(TOKEN_NULL));
qlKeywords.put(KEYWORD_SELECT, new Integer(TOKEN_SELECT));
qlKeywords.put(KEYWORD_TRAVERSE, new Integer(TOKEN_TRAVERSE));
qlKeywords.put(KEYWORD_TRUE, new Integer(TOKEN_TRUE));
qlKeywords.put(KEYWORD_UNIQUE, new Integer(TOKEN_UNIQUE));
qlKeywords.put(KEYWORD_INTERSECT, new Integer(TOKEN_INTERSECT));
qlKeywords.put(KEYWORD_UNION, new Integer(TOKEN_UNION));
qlKeywords.put(OPERATOR_EACH, new Integer(TOKEN_ANY));
}
public QLParser(IExpressionFactory factory) {
super(factory);
}
protected Map<String, Integer> keywordToTokenMap() {
return qlKeywords;
}
protected IExpression parseCondition() {
IExpression expr = parseOr();
if (currentToken == TOKEN_IF) {
nextToken();
IExpression ifTrue = parseOr();
assertToken(TOKEN_ELSE);
nextToken();
expr = factory.condition(expr, ifTrue, parseOr());
}
return expr;
}
protected IExpression parseMember() {
IExpression expr = parseFunction();
String name;
while (currentToken == TOKEN_DOT || currentToken == TOKEN_LB) {
int savePos = tokenPos;
int saveToken = currentToken;
Object saveTokenValue = tokenValue;
nextToken();
if (saveToken == TOKEN_DOT) {
switch (currentToken) {
case TOKEN_IDENTIFIER :
name = (String) tokenValue;
nextToken();
if (currentToken == TOKEN_LP) {
nextToken();
IExpression[] callArgs = parseArray();
assertToken(TOKEN_RP);
nextToken();
expr = factory.memberCall(expr, name, callArgs);
} else
expr = factory.member(expr, name);
break;
default :
tokenPos = savePos;
currentToken = saveToken;
tokenValue = saveTokenValue;
return expr;
}
} else {
IExpression atExpr = parseMember();
assertToken(TOKEN_RB);
nextToken();
expr = factory.at(expr, atExpr);
}
}
return expr;
}
protected IExpression parseFunction() {
if (currentToken == TOKEN_IDENTIFIER) {
Object function = factory.getFunctionMap().get(tokenValue);
if (function != null) {
int savePos = tokenPos;
int saveToken = currentToken;
Object saveTokenValue = tokenValue;
nextToken();
if (currentToken == TOKEN_LP) {
nextToken();
IExpression[] args = currentToken == TOKEN_RP ? IExpressionFactory.NO_ARGS : parseArray();
assertToken(TOKEN_RP);
nextToken();
return factory.function(function, args);
}
tokenPos = savePos;
currentToken = saveToken;
tokenValue = saveTokenValue;
}
}
return parseUnary();
}
protected IExpression parseCollectionLHS() {
IExpression expr;
switch (currentToken) {
case TOKEN_SELECT :
case TOKEN_COLLECT :
case TOKEN_FIRST :
case TOKEN_FLATTEN :
case TOKEN_TRAVERSE :
case TOKEN_LATEST :
case TOKEN_LIMIT :
case TOKEN_INTERSECT :
case TOKEN_UNION :
case TOKEN_UNIQUE :
expr = getVariableOrRootMember(rootVariable);
break;
default :
expr = super.parseCollectionLHS();
}
return expr;
}
protected IExpression parseCollectionRHS(IExpression expr, int funcToken) {
switch (funcToken) {
case TOKEN_SELECT :
expr = factory.select(expr, parseLambdaDefinition());
break;
case TOKEN_COLLECT :
expr = factory.collect(expr, parseLambdaDefinition());
break;
case TOKEN_FIRST :
expr = factory.first(expr, parseLambdaDefinition());
break;
case TOKEN_TRAVERSE :
expr = factory.traverse(expr, parseLambdaDefinition());
break;
case TOKEN_LATEST :
if (currentToken == TOKEN_RP) {
expr = factory.latest(expr);
assertToken(TOKEN_RP);
nextToken();
} else
expr = factory.latest(factory.select(expr, parseLambdaDefinition()));
break;
case TOKEN_FLATTEN :
if (currentToken == TOKEN_RP) {
expr = factory.flatten(expr);
assertToken(TOKEN_RP);
nextToken();
} else
expr = factory.flatten(factory.select(expr, parseLambdaDefinition()));
break;
case TOKEN_LIMIT :
expr = factory.limit(expr, parseCondition());
assertToken(TOKEN_RP);
nextToken();
break;
case TOKEN_INTERSECT :
expr = factory.intersect(expr, parseCondition());
assertToken(TOKEN_RP);
nextToken();
break;
case TOKEN_UNION :
expr = factory.union(expr, parseCondition());
assertToken(TOKEN_RP);
nextToken();
break;
case TOKEN_UNIQUE :
if (currentToken == TOKEN_RP)
expr = factory.unique(expr, factory.constant(null));
else {
expr = factory.unique(expr, parseMember());
assertToken(TOKEN_RP);
nextToken();
}
break;
default :
expr = super.parseCollectionRHS(expr, funcToken);
}
return expr;
}
protected IExpression parseUnary() {
IExpression expr;
switch (currentToken) {
case TOKEN_LB :
nextToken();
expr = factory.array(parseArray());
assertToken(TOKEN_RB);
nextToken();
break;
case TOKEN_ANY :
expr = factory.variable(OPERATOR_EACH);
nextToken();
break;
default :
expr = super.parseUnary();
}
return expr;
}
protected IExpression parseLambdaDefinition() {
boolean endingRC = false;
int anyIndex = -1;
IExpression[] initializers = IExpressionFactory.NO_ARGS;
IExpression[] variables;
if (currentToken == TOKEN_LC) {
// Lambda starts without currying.
endingRC = true;
nextToken();
anyIndex = 0;
variables = parseVariables();
if (variables == null)
// empty means no pipe at the end.
throw syntaxError();
} else {
anyIndex = 0;
variables = parseVariables();
if (variables == null) {
anyIndex = -1;
initializers = parseArray();
assertToken(TOKEN_LC);
nextToken();
endingRC = true;
for (int idx = 0; idx < initializers.length; ++idx) {
IExpression initializer = initializers[idx];
if (initializer instanceof Variable && OPERATOR_EACH.equals(initializer.toString())) {
if (anyIndex == -1)
anyIndex = idx;
else
anyIndex = -1; // Second Each. This is illegal
break;
}
}
if (anyIndex == -1)
throw new IllegalArgumentException("Exaclty one _ must be present among the currying expressions"); //$NON-NLS-1$
variables = parseVariables();
if (variables == null)
// empty means no pipe at the end.
throw syntaxError();
}
}
nextToken();
IExpression body = parseCondition();
if (endingRC) {
assertToken(TOKEN_RC);
nextToken();
}
assertToken(TOKEN_RP);
nextToken();
IExpression each;
IExpression[] assignments;
if (initializers.length == 0) {
if (variables.length != 1)
throw new IllegalArgumentException("Must have exactly one variable unless currying is used"); //$NON-NLS-1$
each = variables[0];
assignments = IExpressionFactory.NO_ARGS;
} else {
if (initializers.length != variables.length)
throw new IllegalArgumentException("Number of currying expressions and variables differ"); //$NON-NLS-1$
if (initializers.length == 1) {
// This is just a map from _ to some variable
each = variables[0];
assignments = IExpressionFactory.NO_ARGS;
} else {
int idx;
each = variables[anyIndex];
assignments = new IExpression[initializers.length - 1];
for (idx = 0; idx < anyIndex; ++idx)
assignments[idx] = factory.assignment(variables[idx], initializers[idx]);
for (++idx; idx < initializers.length; ++idx)
assignments[idx] = factory.assignment(variables[idx], initializers[idx]);
}
}
return factory.lambda(each, assignments, body);
}
private IExpression[] parseVariables() {
int savePos = tokenPos;
int saveToken = currentToken;
Object saveTokenValue = tokenValue;
List<Object> ids = null;
while (currentToken == TOKEN_IDENTIFIER) {
if (ids == null)
ids = new ArrayList<Object>();
ids.add(tokenValue);
nextToken();
if (currentToken == TOKEN_COMMA) {
nextToken();
continue;
}
break;
}
if (currentToken != TOKEN_PIPE) {
// This was not a variable list
tokenPos = savePos;
currentToken = saveToken;
tokenValue = saveTokenValue;
return null;
}
if (ids == null)
// Empty list but otherwise OK
return IExpressionFactory.NO_ARGS;
int top = ids.size();
IExpression[] result = new IExpression[top];
for (int idx = 0; idx < top; ++idx) {
String name = (String) ids.get(idx);
IExpression var = factory.variable(name);
push(var);
result[idx] = var;
}
return result;
}
}