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/* valaforstatement.vala
*
* Copyright (C) 2006-2010 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;
/**
* Represents a for iteration statement in the source code.
*/
public class Vala.ForStatement : Loop, Statement {
private List<Expression> initializer = new ArrayList<Expression> ();
private List<Expression> iterator = new ArrayList<Expression> ();
/**
* Creates a new for statement.
*
* @param condition loop condition
* @param body loop body
* @param source_reference reference to source code
* @return newly created for statement
*/
public ForStatement (Expression? condition, Block body, SourceReference? source_reference = null) {
base (condition, body, source_reference);
}
/**
* Appends the specified expression to the list of initializers.
*
* @param init an initializer expression
*/
public void add_initializer (Expression init) {
init.parent_node = this;
initializer.add (init);
}
/**
* Returns the list of initializers.
*
* @return initializer list
*/
public unowned List<Expression> get_initializer () {
return initializer;
}
/**
* Appends the specified expression to the iterator.
*
* @param iter an iterator expression
*/
public void add_iterator (Expression iter) {
iter.parent_node = this;
iterator.add (iter);
}
/**
* Returns the iterator.
*
* @return iterator
*/
public unowned List<Expression> get_iterator () {
return iterator;
}
public override void accept (CodeVisitor visitor) {
visitor.visit_for_statement (this);
}
public override void accept_children (CodeVisitor visitor) {
foreach (Expression init_expr in initializer) {
init_expr.accept (visitor);
visitor.visit_end_full_expression (init_expr);
}
if (condition != null) {
condition.accept (visitor);
visitor.visit_end_full_expression (condition);
}
foreach (Expression it_expr in iterator) {
it_expr.accept (visitor);
visitor.visit_end_full_expression (it_expr);
}
body.accept (visitor);
}
public override void replace_expression (Expression old_node, Expression new_node) {
base.replace_expression (old_node, new_node);
for (int i=0; i < initializer.size; i++) {
if (initializer[i] == old_node) {
initializer[i] = new_node;
new_node.parent_node = this;
}
}
for (int i=0; i < iterator.size; i++) {
if (iterator[i] == old_node) {
iterator[i] = new_node;
new_node.parent_node = this;
}
}
}
public override bool check (CodeContext context) {
if (checked) {
return !error;
}
checked = true;
// convert to simple loop
var block = new Block (source_reference);
// initializer
foreach (var init_expr in initializer) {
block.add_statement (new ExpressionStatement (init_expr, init_expr.source_reference));
}
// do not generate if block if condition is always true
if (condition == null || condition.is_always_true ()) {
} else if (condition.is_always_false ()) {
// do not generate if block if condition is always false
body.insert_statement (0, new BreakStatement (condition.source_reference));
} else {
// condition
var if_condition = new UnaryExpression (UnaryOperator.LOGICAL_NEGATION, condition, condition.source_reference);
var true_block = new Block (condition.source_reference);
true_block.add_statement (new BreakStatement (condition.source_reference));
var if_stmt = new IfStatement (if_condition, true_block, null, condition.source_reference);
body.insert_statement (0, if_stmt);
}
// iterator
var first_local = new LocalVariable (context.analyzer.bool_type.copy (), get_temp_name (), new BooleanLiteral (true, source_reference), source_reference);
block.add_statement (new DeclarationStatement (first_local, source_reference));
var iterator_block = new Block (source_reference);
foreach (var it_expr in iterator) {
iterator_block.add_statement (new ExpressionStatement (it_expr, it_expr.source_reference));
}
var first_if = new IfStatement (new UnaryExpression (UnaryOperator.LOGICAL_NEGATION, new MemberAccess.simple (first_local.name, source_reference), source_reference), iterator_block, null, source_reference);
body.insert_statement (0, first_if);
body.insert_statement (1, new ExpressionStatement (new Assignment (new MemberAccess.simple (first_local.name, source_reference), new BooleanLiteral (false, source_reference), AssignmentOperator.SIMPLE, source_reference), source_reference));
block.add_statement (new LoopStatement (body, source_reference));
unowned Block parent_block = (Block) parent_node;
parent_block.replace_statement (this, block);
if (!block.check (context)) {
error = true;
}
return !error;
}
}
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