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/* valalambdaexpression.vala
*
* Copyright (C) 2006-2008 Jürg Billeter
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
* Author:
* Jürg Billeter <j@bitron.ch>
*/
using GLib;
using Gee;
/**
* Represents a lambda expression in the source code. Lambda expressions are
* anonymous methods with implicitly typed parameters.
*/
public class Vala.LambdaExpression : Expression {
/**
* The expression body of this lambda expression. Only one of
* expression_body or statement_body may be set.
*/
public Expression expression_body { get; set; }
/**
* The statement body of this lambda expression. Only one of
* expression_body or statement_body may be set.
*/
public Block statement_body { get; set; }
/**
* The generated method.
*/
public Method method { get; set; }
private Gee.List<string> parameters = new ArrayList<string> ();
/**
* Creates a new lambda expression.
*
* @param expression_body expression body
* @param source_reference reference to source code
* @return newly created lambda expression
*/
public LambdaExpression (Expression expression_body, SourceReference source_reference) {
this.source_reference = source_reference;
this.expression_body = expression_body;
}
/**
* Creates a new lambda expression with statement body.
*
* @param statement_body statement body
* @param source_reference reference to source code
* @return newly created lambda expression
*/
public LambdaExpression.with_statement_body (Block statement_body, SourceReference source_reference) {
this.statement_body = statement_body;
this.source_reference = source_reference;
}
/**
* Appends implicitly typed parameter.
*
* @param param parameter name
*/
public void add_parameter (string param) {
parameters.add (param);
}
/**
* Returns copy of parameter list.
*
* @return parameter list
*/
public Gee.List<string> get_parameters () {
return new ReadOnlyList<string> (parameters);
}
public override void accept (CodeVisitor visitor) {
visitor.visit_lambda_expression (this);
visitor.visit_expression (this);
}
public override void accept_children (CodeVisitor visitor) {
if (method == null) {
if (expression_body != null) {
expression_body.accept (visitor);
visitor.visit_end_full_expression (expression_body);
} else if (statement_body != null) {
statement_body.accept (visitor);
}
} else {
method.accept (visitor);
}
}
public override bool is_pure () {
return false;
}
string get_lambda_name (SemanticAnalyzer analyzer) {
var result = "__lambda%d".printf (analyzer.next_lambda_id);
analyzer.next_lambda_id++;
return result;
}
public override bool check (SemanticAnalyzer analyzer) {
if (checked) {
return !error;
}
checked = true;
if (!(target_type is DelegateType)) {
error = true;
Report.error (source_reference, "lambda expression not allowed in this context");
return false;
}
bool in_instance_method = false;
var current_method = analyzer.find_current_method ();
if (current_method != null) {
in_instance_method = (current_method.binding == MemberBinding.INSTANCE);
} else {
in_instance_method = analyzer.is_in_constructor ();
}
var cb = (Delegate) ((DelegateType) target_type).delegate_symbol;
method = new Method (get_lambda_name (analyzer), cb.return_type);
if (!cb.has_target || !in_instance_method) {
method.binding = MemberBinding.STATIC;
}
method.owner = analyzer.current_symbol.scope;
var lambda_params = get_parameters ();
Iterator<string> lambda_param_it = lambda_params.iterator ();
foreach (FormalParameter cb_param in cb.get_parameters ()) {
if (!lambda_param_it.next ()) {
/* lambda expressions are allowed to have less parameters */
break;
}
string lambda_param = lambda_param_it.get ();
var param = new FormalParameter (lambda_param, cb_param.parameter_type);
method.add_parameter (param);
}
if (lambda_param_it.next ()) {
/* lambda expressions may not expect more parameters */
error = true;
Report.error (source_reference, "lambda expression: too many parameters");
return false;
}
if (expression_body != null) {
var block = new Block (source_reference);
block.scope.parent_scope = method.scope;
if (method.return_type.data_type != null) {
block.add_statement (new ReturnStatement (expression_body, source_reference));
} else {
block.add_statement (new ExpressionStatement (expression_body, source_reference));
}
method.body = block;
} else {
method.body = statement_body;
}
method.body.owner = method.scope;
/* lambda expressions should be usable like MemberAccess of a method */
symbol_reference = method;
if (method == null) {
if (expression_body != null) {
expression_body.check (analyzer);
} else if (statement_body != null) {
statement_body.check (analyzer);
}
} else {
method.check (analyzer);
}
value_type = new MethodType (method);
return !error;
}
}
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