flutter/packages/cassowary/lib/constraint.dart
2015-06-25 16:24:21 -07:00

43 lines
1.0 KiB
Dart

// Copyright (c) 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
part of cassowary;
enum Relation { equalTo, lessThanOrEqualTo, greaterThanOrEqualTo, }
class Constraint {
final Relation relation;
final Expression expression;
double priority = Priority.required;
Constraint(this.expression, this.relation);
Constraint operator |(double p) => this..priority = p;
String toString() {
StringBuffer buffer = new StringBuffer();
buffer.write(expression.toString());
switch (relation) {
case Relation.equalTo:
buffer.write(" == 0 ");
break;
case Relation.greaterThanOrEqualTo:
buffer.write(" >= 0 ");
break;
case Relation.lessThanOrEqualTo:
buffer.write(" <= 0 ");
break;
}
buffer.write(" | priority = ${priority}");
if (priority == Priority.required) {
buffer.write(" (required)");
}
return buffer.toString();
}
}