Merge pull request #298 from getodk/features/xpath/variadic-distance-params

Variadic `distance`, minor related XPath geo functionality improvements

Author: eyelidlessness

.changeset/funny-items-know.md

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+---
+"@getodk/xpath": minor
+---
+
+The `xf:distance` function signature is now variadic, consistent with the revised signature specified by ODK XForms.

.changeset/funny-items-know2.md

@@ -0,0 +1,5 @@
+---
+"@getodk/xforms-engine": minor
+---
+
+The `xf:distance` XPath function now accepts multiple arguments. This makes it easier to compute the distance between multiple points within a form's primary instance. Previously, to achieve this, you'd have to introduce a `calculate` which concatenates those points together, then call the distance function with a reference to that `calculate` as the argument.

.changeset/wise-dancers-itch.md

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+---
+"@getodk/xpath": patch
+---
+
+Improved consistency with Collect/JavaRosa:
+
+
+- `area` and `distance` handle a trailing semicolon in serialized semicolon-separated `geopoint` lists
+- `distance` produces an error for invalid input
+- `area` returns `0` for invalid input

packages/common/src/fixtures/xpath-fns/variadic-distance.xml

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+<?xml version="1.0"?>
+<h:html xmlns="http://www.w3.org/2002/xforms" xmlns:h="http://www.w3.org/1999/xhtml"
+  xmlns:ev="http://www.w3.org/2001/xml-events" xmlns:xsd="http://www.w3.org/2001/XMLSchema"
+  xmlns:jr="http://openrosa.org/javarosa" xmlns:orx="http://openrosa.org/xforms"
+  xmlns:odk="http://www.opendatakit.org/xforms">
+  <h:head>
+    <h:title>Examples using the distance() and area() function</h:title>
+    <model odk:xforms-version="1.0.0">
+      <instance>
+        <data id="distance_examples" version="20241025195211">
+          <location1>-6.8137120026589315 39.29392995851879 400 10</location1>
+          <location2>-6.815178491608137 39.29533915133268</location2>
+          <location3>-6.81189589956027 39.2973513889647 600</location3>
+          <location4>-6.81223343508222 39.29735351357036</location4>
+          <geoshape_12341 />
+          <distance_1234 />
+          <area_1234 />
+          <distance_mixed />
+          <distance_via_geoshape />
+          <meta>
+            <instanceID />
+          </meta>
+        </data>
+      </instance>
+      <bind nodeset="/data/location1" readonly="true()" type="string" />
+      <bind nodeset="/data/location2" readonly="true()" type="string" />
+      <bind nodeset="/data/location3" readonly="true()" type="string" />
+      <bind nodeset="/data/location4" readonly="true()" type="string" />
+      <bind nodeset="/data/geoshape_12341" readonly="true()" type="string"
+        calculate="join(&quot;; &quot;,  /data/location1 ,  /data/location2 ,  /data/location3 ,  /data/location4 ,  /data/location1 )" />
+      <bind nodeset="/data/distance_1234" readonly="true()" type="string"
+        calculate="distance( /data/location1 ,  /data/location2 ,  /data/location3 ,  /data/location4 )" />
+      <bind nodeset="/data/area_1234" readonly="true()" type="string"
+        calculate="area( /data/geoshape_12341 )" />
+      <bind nodeset="/data/distance_mixed" readonly="true()" type="string"
+        calculate="distance( /data/location1 ,  /data/location2 ,  /data/location3 ,  /data/location4 , '-6.8137120026589315 39.29392995851879 400 10')" />
+      <bind nodeset="/data/distance_via_geoshape" readonly="true()" type="string"
+        calculate="distance( /data/geoshape_12341 )" />
+      <bind nodeset="/data/meta/instanceID" type="string" readonly="true()" jr:preload="uid" />
+    </model>
+  </h:head>
+  <h:body>
+    <input ref="/data/location1">
+      <label>where 1</label>
+    </input>
+    <input ref="/data/location2">
+      <label>where 2</label>
+    </input>
+    <input ref="/data/location3">
+      <label>where 3</label>
+    </input>
+    <input ref="/data/location4">
+      <label>where 4</label>
+    </input>
+    <input ref="/data/geoshape_12341">
+      <label>geoshape 12341</label>
+    </input>
+    <input ref="/data/distance_1234">
+      <label>distance 1234</label>
+    </input>
+    <input ref="/data/area_1234">
+      <label>area 1234</label>
+    </input>
+    <input ref="/data/distance_mixed">
+      <label>distance 12341 mixed-type arguments</label>
+    </input>
+    <input ref="/data/distance_via_geoshape">
+      <label>distance 12341 via geoshape</label>
+    </input>
+  </h:body>
+</h:html>