From 69fbc9fdd8e4c8da6743e90de409c65bee6e37d6 Mon Sep 17 00:00:00 2001
From: Lionel Sambuc <lionel.sambuc@epfl.ch>
Date: Sat, 25 Jul 2020 08:49:36 +0200
Subject: [PATCH] Set the volume in the parser for Filters

When no volume is provided, create by default a volume containing the
whole space.

This simplifies handling later on, as there is no checks and on-the-fly
generation of that value necessary. This also remove life time issues as
the volume is always present with the same life time as the rest of the
Filter.
---
 src/predictors.rs   |  6 +-----
 src/queries.lalrpop | 22 +++++++++++++++++-----
 src/symbols.rs      |  7 ++-----
 src/validators.rs   |  5 +----
 4 files changed, 21 insertions(+), 19 deletions(-)

diff --git a/src/predictors.rs b/src/predictors.rs
index fd99e44..e1d0109 100644
--- a/src/predictors.rs
+++ b/src/predictors.rs
@@ -1,4 +1,3 @@
-use mercator_db::space;
 use mercator_db::DataBase;
 
 use super::expressions::Predictor;
@@ -18,10 +17,7 @@ impl Predictor for Bag {
         match self {
             Bag::ViewPort(bag) => bag.predict(db),
             Bag::Distinct(bag) => bag.predict(db),
-            Bag::Filter(_, bag) => match bag {
-                None => Ok(db.space(space::Space::universe().name())?.volume()),
-                Some(b) => b.predict(db),
-            },
+            Bag::Filter(_, bag) => bag.predict(db),
             Bag::Complement(bag) => Ok(db.space(bag.space())?.volume() - bag.predict(db)?),
             Bag::Intersection(lh, rh) => {
                 let l = lh.predict(db)?;
diff --git a/src/queries.lalrpop b/src/queries.lalrpop
index 1760688..0086a56 100644
--- a/src/queries.lalrpop
+++ b/src/queries.lalrpop
@@ -189,13 +189,25 @@ Union: symbols::Bag = {
 Filter: symbols::Bag = {
 //     "filter" "(" <p:Predicates> "," <b:Bags> ")" =>
     "filter" "(" <b:Bags> ")" =>
-        symbols::Bag::Filter(None, Some(Box::new(b))),
-    "filter" "(" <p:Predicates> <b:("," <Bags> )?> ")" =>
+        symbols::Bag::Filter(None, Box::new(b)),
+    "filter" "(" <p:Predicates> <b:("," <Bags> )?> ")" => {
         match b {
-            None => symbols::Bag::Filter(Some(p), None),
-            Some(b) => symbols::Bag::Filter(Some(p), Some(Box::new(b))),
+            None => {
+                let (low, high) = Space::universe().bounding_box();
+                let low: Vec<_> = low.into();
+                let high: Vec<_> = high.into();
+                let shape = symbols::Shape::HyperRectangle(
+                    Space::universe().name().clone(),
+                    vec![
+                        symbols::LiteralPosition(low.into_iter().map(symbols::LiteralNumber::Float).collect()),
+                        symbols::LiteralPosition(high.into_iter().map(symbols::LiteralNumber::Float).collect()),
+                    ],
+                );
+                symbols::Bag::Filter(Some(p), Box::new(symbols::Bag::Inside(shape)))
+            }
+            Some(b) => symbols::Bag::Filter(Some(p), Box::new(b)),
         }
-
+    },
 };
 
 Predicates: symbols::Predicate = {
diff --git a/src/symbols.rs b/src/symbols.rs
index 33be326..bb8d7bd 100644
--- a/src/symbols.rs
+++ b/src/symbols.rs
@@ -61,7 +61,7 @@ pub enum Bag {
     ViewPort(Box<Bag>),
     // Bags
     Distinct(Box<Bag>),
-    Filter(Option<Predicate>, Option<Box<Bag>>),
+    Filter(Option<Predicate>, Box<Bag>),
     Complement(Box<Bag>),
     Intersection(Box<Bag>, Box<Bag>),
     Union(Box<Bag>, Box<Bag>),
@@ -77,10 +77,7 @@ impl Bag {
         match self {
             Bag::ViewPort(bag) => bag.space(),
             Bag::Distinct(bag) => bag.space(),
-            Bag::Filter(_, bag) => match bag {
-                None => space::Space::universe().name(),
-                Some(b) => b.space(),
-            },
+            Bag::Filter(_, bag) => bag.space(),
             Bag::Complement(bag) => bag.space(),
             Bag::Intersection(lh, _) => {
                 // We are assuming lh and rh are in the same space.
diff --git a/src/validators.rs b/src/validators.rs
index 4c8f265..5787891 100644
--- a/src/validators.rs
+++ b/src/validators.rs
@@ -56,10 +56,7 @@ impl Validator for Bag {
         match self {
             Bag::ViewPort(bag) => bag.validate(),
             Bag::Distinct(bag) => bag.validate(),
-            Bag::Filter(_, bag) => match bag {
-                None => Ok(LiteralPosition(vec![]).get_type()),
-                Some(b) => b.validate(),
-            },
+            Bag::Filter(_, bag) => bag.validate(),
             Bag::Complement(bag) => bag.validate(),
             Bag::Intersection(lh, rh) => compare_bag_types(lh, rh),
             Bag::Union(lh, rh) => compare_bag_types(lh, rh),