[PATCH] Search keywords "child" and "parent"

[Matt]

It has been noted that search keywords for parent/child relationships would be useful, ​http://www.mail-archive.com/josm-dev@openstreetmap.org/msg01869.html

[Matt]

Patch to add "child" and "parent" keywords to search.

[avar]

Nice patch, but the child and parent operators can't be used in conjunction with any other search terms. I.e. "type:way" and then "child" works for finding all nodes which belong to ways, but "type:way child" doesn't. Neither does combining them with anything else.

And "parent child" doesn't work, which I would expect to find all relations a way belongs to and all of its nodes when I have a way selected that's a member of a relation.

[Matt]

Here's a better patch, which allows expression "arguments" to the parent and child keywords. For example, to select all neighbouring ways of a selected way, "parent(child(selected)) type:way" works nicely. The parentheses are optional for single-argument expressions, but its more readable to keep them. (i.e: the above could have been "parent child selected type:way")

[Matt]

A better patch for parent/child relationship search.

[avar]

Replying to Matt:

Here's a better patch, which allows expression "arguments" to the parent and child keywords. For example, to select all neighbouring ways of a selected way, "parent(child(selected)) type:way" works nicely. The parentheses are optional for single-argument expressions, but its more readable to keep them. (i.e: the above could have been "parent child selected type:way")

This minor patch improves upon your patch:

• "child" or "parent" i.e. without argument is no longer a NullPointerException but equivalent to "parent()" or "child()" respectively. I.e. it'll match everything that's the child or parent of some other object. I thought about making it an error about "child/parent without argument" but that would be inconsistent with the rest of the search syntax where omitting optional expressions always means "match everything".

• The operators now stringify to child() and parent() instead of childof() and parentof()

Other than that I've tested this patch extensively and it's working just as expected. I can now do, for example:

parent(parent(type:node ^highway$:^traffic_signals$) ^highway$:^trunk$) ^type$:^route$

To select all route relations which cover trunk ways which have a traffic signal.

[avar]

attachment:josm.child-parent-search.3.patch​ with minor fixes

[stoecker]

In r1603.