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/* valasliceexpression.vala
*
* Copyright (C) 2009 Robin Sonefors
* Copyright (C) 2009-2013 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:
* Robin Sonefors <ozamosi@flukkost.nu>
* Jürg Billeter <j@bitron.ch>
*/
using GLib;
/**
* Represents an array slice expression.
*
* {{{ foo[1:5] }}}
*/
public class Vala.SliceExpression : Expression {
public Expression container {
get {
return _container;
}
private set {
_container = value;
_container.parent_node = this;
}
}
public Expression start {
get {
return _start;
}
private set {
_start = value;
_start.parent_node = this;
}
}
public Expression stop {
get {
return _stop;
}
private set {
_stop = value;
_stop.parent_node = this;
}
}
/**
* Null-safe access.
*/
public bool null_safe_access { get; set; }
Expression _container;
Expression _start;
Expression _stop;
public SliceExpression (Expression container, Expression start, Expression stop, SourceReference? source_reference = null) {
this.container = container;
this.start = start;
this.stop = stop;
this.source_reference = source_reference;
}
public override void accept (CodeVisitor visitor) {
visitor.visit_slice_expression (this);
visitor.visit_expression (this);
}
public override void accept_children (CodeVisitor visitor) {
container.accept (visitor);
start.accept (visitor);
stop.accept (visitor);
}
public override void replace_expression (Expression old_node, Expression new_node) {
if (container == old_node) {
container = new_node;
}
if (start == old_node) {
start = new_node;
}
if (stop == old_node) {
stop = new_node;
}
}
public override bool is_pure () {
return false;
}
public override bool is_accessible (Symbol sym) {
return container.is_accessible (sym) && start.is_accessible (sym) && stop.is_accessible (sym);
}
public override bool check (CodeContext context) {
if (checked) {
return !error;
}
checked = true;
if (null_safe_access) {
error = !base.check (context);
return !error;
}
if (!container.check (context)) {
error = true;
return false;
}
if (container.value_type is ArrayType) {
unowned ArrayType array_type = (ArrayType) container.value_type;
start.target_type = array_type.length_type.copy ();
stop.target_type = array_type.length_type.copy ();
}
if (!start.check (context)) {
error = true;
return false;
}
if (!stop.check (context)) {
error = true;
return false;
}
if (container.value_type == null) {
error = true;
Report.error (container.source_reference, "Invalid container expression");
return false;
}
if (lvalue) {
error = true;
Report.error (container.source_reference, "Slice expressions cannot be used as lvalue");
return false;
}
if (container.value_type is ArrayType) {
value_type = container.value_type.copy ();
value_type.value_owned = false;
// inline allocated results are not compatible with non-constant start/stop expressions
unowned ArrayType array_type = (ArrayType) value_type;
array_type.fixed_length = false;
array_type.inline_allocated = false;
array_type.length = null;
value_type.check (context);
/* check if the index is of type integer */
if (!(start.value_type is IntegerType || start.value_type is EnumValueType)) {
error = true;
Report.error (start.source_reference, "Expression of integer type expected");
}
if (!(stop.value_type is IntegerType || stop.value_type is EnumValueType)) {
error = true;
Report.error (stop.source_reference, "Expression of integer type expected");
}
} else {
var slice_method = container.value_type.get_member ("slice") as Method;
if (slice_method != null) {
var slice_call = new MethodCall (new MemberAccess (container, "slice", source_reference), source_reference);
slice_call.add_argument (start);
slice_call.add_argument (stop);
slice_call.target_type = this.target_type;
parent_node.replace_expression (this, slice_call);
return slice_call.check (context);
}
error = true;
Report.error (source_reference, "The expression `%s' does not denote an array", container.value_type.to_string ());
}
return !error;
}
public override void emit (CodeGenerator codegen) {
container.emit (codegen);
start.emit (codegen);
stop.emit (codegen);
codegen.visit_slice_expression (this);
codegen.visit_expression (this);
}
public override void get_defined_variables (Collection<Variable> collection) {
container.get_defined_variables (collection);
start.get_defined_variables (collection);
stop.get_defined_variables (collection);
}
public override void get_used_variables (Collection<Variable> collection) {
container.get_used_variables (collection);
start.get_used_variables (collection);
stop.get_used_variables (collection);
}
}
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