/
list.dart
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/
list.dart
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// Copyright 2019 Google Inc. Use of this source code is governed by an
// MIT-style license that can be found in the LICENSE file or at
// https://opensource.org/licenses/MIT.
import 'dart:collection';
import 'package:collection/collection.dart';
import '../callable.dart';
import '../exception.dart';
import '../module/built_in.dart';
import '../value.dart';
/// The global definitions of Sass list functions.
final global = UnmodifiableListView([
_length, _nth, _setNth, _join, _append, _zip, _index, _isBracketed, //
_separator.withName("list-separator")
]);
/// The Sass list module.
final module = BuiltInModule("list", functions: [
_length, _nth, _setNth, _join, _append, _zip, _index, _isBracketed, //
_separator, _slash
]);
final _length = _function(
"length", r"$list", (arguments) => SassNumber(arguments[0].asList.length));
final _nth = _function("nth", r"$list, $n", (arguments) {
var list = arguments[0];
var index = arguments[1];
return list.asList[list.sassIndexToListIndex(index, "n")];
});
final _setNth = _function("set-nth", r"$list, $n, $value", (arguments) {
var list = arguments[0];
var index = arguments[1];
var value = arguments[2];
var newList = list.asList.toList();
newList[list.sassIndexToListIndex(index, "n")] = value;
return arguments[0].withListContents(newList);
});
final _join = _function(
"join", r"$list1, $list2, $separator: auto, $bracketed: auto", (arguments) {
var list1 = arguments[0];
var list2 = arguments[1];
var separatorParam = arguments[2].assertString("separator");
var bracketedParam = arguments[3];
ListSeparator separator;
if (separatorParam.text == "auto") {
if (list1.separator != ListSeparator.undecided) {
separator = list1.separator;
} else if (list2.separator != ListSeparator.undecided) {
separator = list2.separator;
} else {
separator = ListSeparator.space;
}
} else if (separatorParam.text == "space") {
separator = ListSeparator.space;
} else if (separatorParam.text == "comma") {
separator = ListSeparator.comma;
} else if (separatorParam.text == "slash") {
separator = ListSeparator.slash;
} else {
throw SassScriptException(
'\$separator: Must be "space", "comma", "slash", or "auto".');
}
var bracketed = bracketedParam is SassString && bracketedParam.text == 'auto'
? list1.hasBrackets
: bracketedParam.isTruthy;
var newList = [...list1.asList, ...list2.asList];
return SassList(newList, separator, brackets: bracketed);
});
final _append =
_function("append", r"$list, $val, $separator: auto", (arguments) {
var list = arguments[0];
var value = arguments[1];
var separatorParam = arguments[2].assertString("separator");
ListSeparator separator;
if (separatorParam.text == "auto") {
separator = list.separator == ListSeparator.undecided
? ListSeparator.space
: list.separator;
} else if (separatorParam.text == "space") {
separator = ListSeparator.space;
} else if (separatorParam.text == "comma") {
separator = ListSeparator.comma;
} else if (separatorParam.text == "slash") {
separator = ListSeparator.slash;
} else {
throw SassScriptException(
'\$separator: Must be "space", "comma", "slash", or "auto".');
}
var newList = [...list.asList, value];
return list.withListContents(newList, separator: separator);
});
final _zip = _function("zip", r"$lists...", (arguments) {
var lists = arguments[0].asList.map((list) => list.asList).toList();
if (lists.isEmpty) {
return const SassList.empty(separator: ListSeparator.comma);
}
var i = 0;
var results = <SassList>[];
while (lists.every((list) => i != list.length)) {
results.add(SassList(lists.map((list) => list[i]), ListSeparator.space));
i++;
}
return SassList(results, ListSeparator.comma);
});
final _index = _function("index", r"$list, $value", (arguments) {
var list = arguments[0].asList;
var value = arguments[1];
var index = list.indexOf(value);
return index == -1 ? sassNull : SassNumber(index + 1);
});
final _separator = _function("separator", r"$list", (arguments) {
switch (arguments[0].separator) {
case ListSeparator.comma:
return SassString("comma", quotes: false);
case ListSeparator.slash:
return SassString("slash", quotes: false);
default:
return SassString("space", quotes: false);
}
});
final _isBracketed = _function("is-bracketed", r"$list",
(arguments) => SassBoolean(arguments[0].hasBrackets));
final _slash = _function("slash", r"$elements...", (arguments) {
var list = arguments[0].asList;
if (list.length < 2) {
throw SassScriptException("At least two elements are required.");
}
return SassList(list, ListSeparator.slash);
});
/// Like [new BuiltInCallable.function], but always sets the URL to `sass:list`.
BuiltInCallable _function(
String name, String arguments, Value callback(List<Value> arguments)) =>
BuiltInCallable.function(name, arguments, callback, url: "sass:list");