MapCSS/0.2/Proposal lists

Proposal

Some keys in OpenStreetMap allow (resp. it is common) the use of lists as values, e.g. cuisine=* and ref=*.

Also, lists can be useful for eval statements, e.g. to collect the Names or refs of route relations on the ways.

List selector

The value is treated as a semicolon-separated string, e.g. "regional;asian". If the value does not contain a semicolon, it is treated as list with only one value, e.g. "regional".

node[cuisine~=regional]    /* Matches against all nodes where the cuisine tags contains "regional" as list element */

Support:

Feature	JOSM	pgm
List selector *[cuisine~=regional]	+	+

List eval functions

Data type list: A list of values, may be empty (equals none).

The following functions may be used with lists:

General functions

Function	Description	Example	JOSM	pgm
list(a, b, ...) => list	create list of values	list("foo", "bar")	+	+
get(lst:list, i:int) => value	return the ith element of the list lst (counting starts at 0); returns none if i is out of range.	get(list("foo", "bar"), 1) => "bar"	+	+
set(lst:list, i:int, v:value) => list	set the ith element of the list lst to value v	set(list("foo", "bar"), 1, "baz") => list("foo", "baz")	+	+
append(lst:list, v:value) => list	append the value v to list lst	append(list("foo", "bar"), "baz") => list("foo", "bar", "baz")	-	+
split(sep:string, str:string) => list	splits string str at occurrences of the separator string sep, returns a list	split(";", "foo;bar") => list("foo", "bar")	+	+
join(sep:string, lst:list) => string	joins a list with sep as separator	join(";", list("foo", "bar")) => "foo;bar"	-	+
count(lst:list) => int	count of elements in the list lst	count(list("foo", "bar")) => 2	+	+
contains(lst:list, v:value) => boolean	returns true if list lst contains value v	contains(list("foo", "bar"), "bar") => true	-	+
search(lst:list, v:value) => int	returns first index of value v in list lst or none if not found.	search(list("foo", "bar"), "bar") => 1	-	+
unique(lst:list) => list	removes duplicate values from list lst	unique(list("foo", "bar", "foo")) => list("foo", "bar")	-	+
sort(lst:list) => list	order list alphabetically ascending	sort(list("foo", "bar", "12", "1", "2")) => list("1", "12", "2", "bar", "foo")	-	+
natsort(lst:list) => list	order list 'natural' sort order	sort(list("foo", "bar", "12", "1", "2")) => list("1", "2", "12", "bar", "foo")	-	+
min(lst:list) => number	returns lowest of the input values	min(list(12, 1, 2)) => 1	-	+
max(lst:list) => number	returns highest of the input values	max(list(12, 1, 2)) => 12	-	+
sum(lst:list) => number	returns the sum of all input values	sum(list(12, 1, 2)) => 15	-	-
reverse(lst:list) => list	returns the list in reverse order	reverse(list("foo", "bar", "baz")) => list("baz", "bar", "foo")	-	-
range(start:number, end:number[, step:number]) => list	returns a list of numbers, starting with start and ending with end increased by step (default: 1)	range(-5, -10, -2.5) => list(-5, -7.5, -10)	-	-

Examples

Label all restaurants with asian cuisine

*[amenity=restaurant][cuisine~=asian] {
  text: name;
}

Show route refs on ways

Collect all route refs on their respective ways and print them joined after sorting naturally.

relation[type=route][ref] way {
  refs: append(prop(refs), parent_tag(ref));
  set .has_refs;
}

way.has_refs {
  color: #ff0000;
  width: 2;
  text: join(", ", natsort(prop(refs)));
  text-position: line;
}

References

List selector

• JOSM: http://josm.openstreetmap.de/wiki/Help/Styles/MapCSSImplementation#Conditionselector
• pgmapcss: https://github.com/plepe/pgmapcss/blob/master/doc/MapCSS.creole#condition-selector

List eval functions

• JOSM: http://josm.openstreetmap.de/wiki/Help/Styles/MapCSSImplementation#Evalexpressions
• pgmapcss: https://github.com/plepe/pgmapcss/blob/master/doc/eval.creole#list-functions