diff --git a/src/executors.rs b/src/executors.rs
index 1d99978..8633292 100644
--- a/src/executors.rs
+++ b/src/executors.rs
@@ -40,6 +40,18 @@ fn complement_helper(
     }
 }
 
+fn view_port(core_id: &str, parameters: &CoreQueryParameters, bag: &Bag) -> mercator_db::ResultSet {
+    if let Some((low, high)) = parameters.view_port {
+        let vp = Bag::Inside(Shape::HyperRectangle(
+            bag.space().clone(),
+            vec![low.into(), high.into()],
+        ));
+        intersection(core_id, parameters, &vp, bag)
+    } else {
+        bag.execute(core_id, parameters)
+    }
+}
+
 fn distinct(core_id: &str, parameters: &CoreQueryParameters, bag: &Bag) -> mercator_db::ResultSet {
     match bag.execute(core_id, parameters) {
         e @ Err(_) => e,
@@ -282,6 +294,7 @@ impl Executor for Bag {
         let core = parameters.db.core(core_id)?;
 
         match self {
+            Bag::ViewPort(bag) => view_port(core_id, parameters, bag),
             Bag::Distinct(bag) => distinct(core_id, parameters, bag),
             Bag::Filter(predicate, bag) => filter(core_id, parameters, predicate, bag),
             Bag::Complement(bag) => complement(core_id, parameters, core, bag),
diff --git a/src/main.rs b/src/main.rs
index 37eb6ba..b287394 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -31,6 +31,7 @@ fn main() {
         db: &db,
         output_space: None,
         threshold_volume: None,
+        view_port: &None,
         resolution: None,
     };
     let parser = QueryParser::new();
@@ -51,7 +52,7 @@ fn main() {
                 }
 
                 info_time!("Interpretation");
-                let mut parse;
+                let parse;
                 {
                     info_time!("Parsing");
                     parse = parser.parse(&input);
diff --git a/src/predictors.rs b/src/predictors.rs
index 706e890..e1d0109 100644
--- a/src/predictors.rs
+++ b/src/predictors.rs
@@ -15,6 +15,7 @@ impl Predictor for Projection {
 impl Predictor for Bag {
     fn predict(&self, db: &DataBase) -> Result<f64, String> {
         match self {
+            Bag::ViewPort(bag) => bag.predict(db),
             Bag::Distinct(bag) => bag.predict(db),
             Bag::Filter(_, bag) => bag.predict(db),
             Bag::Complement(bag) => Ok(db.space(bag.space())?.volume() - bag.predict(db)?),
diff --git a/src/queries.lalrpop b/src/queries.lalrpop
index 9c42795..b54fbc2 100644
--- a/src/queries.lalrpop
+++ b/src/queries.lalrpop
@@ -135,7 +135,10 @@ Aggregations: symbols::Aggregation = {
 //*********************************************************************/
 // SELECTING / FILTERING DATA                                         */
 //*********************************************************************/
-pub Filters = { Bags };
+pub Filters: symbols::Bag = {
+    <Bags> =>
+        symbols::Bag::ViewPort(Box::new(<>))
+};
 
 // All these expressions generate bags.
 Bags: symbols::Bag = {
diff --git a/src/symbols.rs b/src/symbols.rs
index 5d9cfd4..24094c1 100644
--- a/src/symbols.rs
+++ b/src/symbols.rs
@@ -57,6 +57,9 @@ struct Transform {
 /**********************************************************************/
 #[derive(Clone, Debug)]
 pub enum Bag {
+    // This is an implicit operator, inserted by the parser. Never to be used directly.
+    ViewPort(Box<Bag>),
+    // Bags
     Distinct(Box<Bag>),
     Filter(Option<Predicate>, Box<Bag>),
     Complement(Box<Bag>),
@@ -72,6 +75,7 @@ pub enum Bag {
 impl Bag {
     pub fn space(&self) -> &String {
         match self {
+            Bag::ViewPort(bag) => bag.space(),
             Bag::Distinct(bag) => bag.space(),
             Bag::Filter(_, bag) => bag.space(),
             Bag::Complement(bag) => bag.space(),
@@ -333,6 +337,17 @@ impl From<&LiteralPosition> for Vec<f64> {
     }
 }
 
+impl From<&Vec<f64>> for LiteralPosition {
+    fn from(v: &Vec<f64>) -> Self {
+        let mut lv = Vec::with_capacity(v.len());
+        for value in v {
+            lv.push(LiteralNumber::Float(*value));
+        }
+
+        LiteralPosition(lv)
+    }
+}
+
 impl PartialOrd for LiteralPosition {
     fn partial_cmp(&self, other: &LiteralPosition) -> Option<Ordering> {
         let LiteralPosition(lh) = self;
diff --git a/src/validators.rs b/src/validators.rs
index 69cfcc1..3b63858 100644
--- a/src/validators.rs
+++ b/src/validators.rs
@@ -54,6 +54,7 @@ impl Validator for Bag {
         }
 
         match self {
+            Bag::ViewPort(bag) => bag.validate(),
             Bag::Distinct(bag) => bag.validate(),
             Bag::Filter(_, bag) => bag.validate(),
             Bag::Complement(bag) => bag.validate(),