package com.creativewidgetworks.goldparser.simple3.rulehandlers;
import java.util.List;
import com.creativewidgetworks.goldparser.engine.ParserException;
import com.creativewidgetworks.goldparser.engine.Reduction;
import com.creativewidgetworks.goldparser.parser.ProcessRule;
import com.creativewidgetworks.goldparser.parser.Scope;
import com.creativewidgetworks.goldparser.parser.Variable;
import com.creativewidgetworks.goldparser.parser.GOLDParser;
import com.creativewidgetworks.goldparser.simple3.Simple3;
@ProcessRule(rule="<Value> ::= Id ( <OptionalArgumentList> )")
/**
* Rule handler for the call function rule.
*
* Calling function ID with no return value:
* ID(<optional_args>)
*
* Calling function ID returning a value:
* result = ID(<optional_args>)
*
* @author Ralph Iden (http://www.creativewidgetworks.com)
* @version 5.0.0
*/
public class FunctionCall extends Reduction {
private final GOLDParser theParser;
private final String functionName;
private final List<Reduction> arguments;
public FunctionCall(GOLDParser parser) {
theParser = parser;
Reduction reduction = parser.getCurrentReduction();
functionName = reduction.get(0).getData().toString();
if (reduction.get(2).asReduction() instanceof Arguments) {
arguments = (List<Reduction>)reduction.get(2).asReduction().getValue().asObject();
} else {
// This handles the single parameter case
Arguments args = new Arguments(reduction.get(2).asReduction());
arguments = (List<Reduction>)args.getValue().asObject();
}
}
@Override
public Variable getValue() {
Scope newScope = new Scope(Function.FUNCTION_PREFIX + functionName, theParser.getCurrentScope());
Scope oldScope = theParser.setCurrentScope(newScope);
try {
// Retrieve the function Reduction, set parameters, and execute the function
Variable var = theParser.getProgramVariable(Function.FUNCTION_PREFIX + functionName);
if (var != null) {
Function fn = (Function)var.asObject();
List<String> parameters = fn.getParameters();
// Make sure we have the proper number of calling parameters
if (parameters.size() != arguments.size()) {
throw new ParserException(Simple3.formatMessage("error.function_argument_count",
String.valueOf(parameters.size()), String.valueOf(arguments.size())));
}
// Set the function parameters -- these will be stored under the function's
// scope and will not be visible outside of the function. Any variables
// in other scopes having the same name will not be visible to the function.
for (int i = 0; i < parameters.size(); i++) {
theParser.setProgramVariable(parameters.get(i), arguments.get(i).getValue());
}
Reduction statements = fn.getStatements();
if (statements != null) {
statements.execute();
var = statements.getValue();
}
// Simple3 doesn't allow a simple RETURN without a value hence this
// path will never be executed. The code remains to support other
// syntaxes that allow an empty return statement. These lines of
// code will be flagged as untested by the coverage tool when the
// Simple3 tests are run.
if (var == null) {
var = new Variable("");
}
} else {
throw new ParserException(Simple3.formatMessage("error.function_undefined", functionName));
}
return var;
} finally {
theParser.setCurrentScope(oldScope);
}
}
}