Skip to content

Fixes inconsistencies in definition of evaluation of property path with sequence #351

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
hartig merged 4 commits into from
Jan 23, 2026
Merged

Fixes inconsistencies in definition of evaluation of property path with sequence #351

Changes from 3 commits
Commits
Show all changes
4 commits
Select commit Hold shift + click to select a range
6eefd35
Fixes inconsistencies in definition of evaluation of property path wi…
hartig Jan 18, 2026
8b78815
changes the order of things in the definition of evaluation of proper…
hartig Jan 18, 2026
9003d9c
adds missing space
hartig Jan 19, 2026
6297ece
v -> prjVar
hartig Jan 23, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
8 changes: 4 additions & 4 deletions spec/index.html
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -9948,10 +9948,10 @@ <h3>Property Path Patterns</h3>
<div class="defn">
<p><b>Definition: <span id="defn_evalPP_sequence">Evaluation of Sequence Property Path</span></b></p>
<p>Let <var>ppe<sub>1</sub></var> and <var>ppe<sub>2</sub></var> be <a href="#defn_AlgebraicPropertyPathExpression">algebraic property path expressions</a>. Let |V| be a fresh variable.</p>
<pre class="nohighlight"><var>A</var> = <a href="#defn_algJoin" class="algFct">Join</a>( ppeval(<var>X</var>, <var>ppe<sub>1</sub></var>, <var>V</var>), ppeval(<var>V</var>, <var>ppe<sub>2</sub></var>, <var>Y</var>) )</pre>
<pre class="nohighlight">ppeval(<var>X</var>, <a href="#defn_ppeSeq" class="ppeOp">Seq</a>(<var>ppe<sub>1</sub></var>, <var>ppe<sub>2</sub></var>), <var>Y</var>) = <a href="#defn_algProject" class="algFct">Project</a>(<var>A</var>, <var>PV</var>)</pre>
<p>where |PV| = { |v| ∈ {|X|,|Y|} | |v| is a variable}.</p>
<div class="issue" data-number="266"><a href="#defn_algJoin" class="algFct">Join</a> produces a multiset of solution mappings but <a href="#defn_algProject" class="algFct">Project</a> expects a sequence as its first argument. Moreover, <a href="#defn_algProject" class="algFct">Project</a> produces a sequence but ppeval(..) should be a multiset.</div>
<pre class="nohighlight">ppeval(<var>X</var>, <a href="#defn_ppeSeq" class="ppeOp">Seq</a>(<var>ppe<sub>1</sub></var>, <var>ppe<sub>2</sub></var>), <var>Y</var>) = <a href="#defn_algToMultiSet" class="algFct">ToMultiSet</a>( <a href="#defn_algProject" class="algFct">Project</a>(<a href="#defn_algToList" class="algFct">ToList</a>(<var>A</var>), <var>PV</var>) )</pre>
<p>where |A| =
Copy link
Contributor

@afs afs Jan 22, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Miinor/preference: I find it easier if things are defined before they are used -- i.e. A = before ToList(A).

Copy link
Contributor Author

@hartig hartig Jan 23, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Honestly, I don't find that easier. At least not in the way it looks like at the moment (i.e., before this PR):

Image

There I am just wondering: what is this A about, why isn't this definition just defining the ppeval as all other definitions in this section do?

<a href="#defn_algJoin" class="algFct">Join</a>( `ppeval`(|X|, <var>ppe<sub>1</sub></var>, |V|), `ppeval`(|V|, <var>ppe<sub>2</sub></var>, |Y|) )
and |PV| = { |v| ∈ {|X|,|Y|} | |v| is a variable }.</p>
</div>
<p>Informally, this is the same as:</p>
<pre class="nohighlight">SELECT * { <var>X</var> <var>P<sub>1</sub></var> _:a . _:a <var>P<sub>2</sub></var> <var>Y</var> }</pre>
Expand Down
Loading