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// Copyright (c) 2023, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
import '../back_end/code_writer.dart';
import '../constants.dart';
import 'piece.dart';
/// A piece for a series of binary expressions at the same precedence, like:
///
/// a + b + c
class InfixPiece extends Piece {
/// The series of operands.
///
/// Since we don't split on both sides of the operator, the operators will be
/// embedded in the operand pieces. If the operator is a hanging one, it will
/// be in the preceding operand, so `1 + 2` becomes "Infix(`1 +`, `2`)".
/// A leading operator like `foo as int` becomes "Infix(`foo`, `as int`)".
final List<Piece> _operands;
InfixPiece(this._operands);
@override
List<State> get additionalStates => const [State.split];
@override
void format(CodeWriter writer, State state) {
if (state == State.unsplit) {
writer.pushAllowNewlines(false);
} else {
writer.pushIndent(Indent.expression);
}
for (var i = 0; i < _operands.length; i++) {
// We can format each operand separately if the operand is on its own
// line. This happens when the operator is split and we aren't the first
// or last operand.
var separate = state == State.split && i > 0 && i < _operands.length - 1;
writer.format(_operands[i], separate: separate);
if (i < _operands.length - 1) writer.splitIf(state == State.split);
}
if (state == State.unsplit) {
writer.popAllowNewlines();
} else {
writer.popIndent();
}
}
@override
void forEachChild(void Function(Piece piece) callback) {
_operands.forEach(callback);
}
@override
State? fixedStateForPageWidth(int pageWidth) {
var totalLength = 0;
for (var operand in _operands) {
// If any operand contains a newline, then we have to split.
if (operand.containsNewline) return State.split;
totalLength += operand.totalCharacters;
if (totalLength > pageWidth) break;
}
// If the total length doesn't fit in the page, then we have to split.
if (totalLength > pageWidth) return State.split;
return null;
}
}