3 files changed, 51 insertions, 1 deletions

diff --git a/src/fexpr/grammar.lalrpop b/src/fexpr/grammar.lalrpop
index 9584536..9eef21a 100644
--- a/src/fexpr/grammar.lalrpop
+++ b/src/fexpr/grammar.lalrpop
@@ -7,6 +7,7 @@ use super::{
 
     DateProducer,
     DurationProducer,
+    CountProducer,
 };
 use evtclib::Boss;
 use std::collections::HashSet;
@@ -73,6 +74,7 @@ LogPredicate: Box<dyn filters::log::LogFilter> = {
 
     <Comparison<DateProducer>>,
     <Comparison<DurationProducer>>,
+    <Comparison<CountProducer>>,
 
     "(" <LogFilter> ")",
 }
@@ -215,6 +217,11 @@ DurationProducer: Box<dyn DurationProducer> = {
     "-duration" => filters::values::duration(),
 }
 
+CountProducer: Box<dyn CountProducer> = {
+    <integer> => filters::values::constant(<>.parse().unwrap()),
+    "count" "(" "player" ":" <PlayerFilter> ")" => filters::values::player_count(<>),
+}
+
 match {
     "player" => "player",
     "not" => "not",
@@ -223,10 +230,12 @@ match {
     "any" => "any",
     "all" => "all",
     "exists" => "exists",
+    "count" => "count",
 
     r"\d\d\d\d-\d\d-\d\d \d\d:\d\d:\d\d" => datetime,
     r"\d\d\d\d-\d\d-\d\d" => date,
     r"((\d+m ?)?\d+s)|(\d+m)" => duration,
+    r"\d+" => integer,
     r"[[:alpha:]][\w]*" => word,
     r#""[^"]*""# => string,
 
diff --git a/src/fexpr/mod.rs b/src/fexpr/mod.rs
index 1738e44..f765acf 100644
--- a/src/fexpr/mod.rs
+++ b/src/fexpr/mod.rs
@@ -13,6 +13,7 @@ use thiserror::Error;
 
 trait DateProducer = filters::values::Producer<Output = chrono::DateTime<chrono::Utc>>;
 trait DurationProducer = filters::values::Producer<Output = chrono::Duration>;
+trait CountProducer = filters::values::Producer<Output = u8>;
 
 lalrpop_mod!(#[allow(clippy::all)] pub grammar, "/fexpr/grammar.rs");
 
diff --git a/src/filters/values.rs b/src/filters/values.rs
index 141aecd..df5b805 100644
--- a/src/filters/values.rs
+++ b/src/filters/values.rs
@@ -13,12 +13,14 @@
 //! the two resulting values with the given comparison operator.
 use std::{
     cmp::Ordering,
+    convert::TryFrom,
     fmt::{self, Debug},
 };
 
 use chrono::{DateTime, Duration, Utc};
+use evtclib::Agent;
 
-use super::{log::LogFilter, Filter, Inclusion};
+use super::{log::LogFilter, player::PlayerFilter, Filter, Inclusion};
 use crate::{EarlyLogResult, LogResult};
 
 /// A producer for a given value.
@@ -194,6 +196,44 @@ pub fn duration() -> Box<dyn Producer<Output = Duration>> {
     Box::new(DurationProducer)
 }
 
+#[derive(Debug)]
+struct PlayerCountProducer(Box<dyn PlayerFilter>);
+
+impl Producer for PlayerCountProducer {
+    type Output = u8;
+
+    fn produce_early(&self, early_log: &EarlyLogResult) -> Option<Self::Output> {
+        let mut count = 0;
+        for agent in &early_log.evtc.agents {
+            if !agent.is_player() {
+                continue;
+            }
+
+            let agent = Agent::try_from(agent);
+            if let Ok(agent) = agent {
+                let result = self.0.filter_early(&agent);
+                match result {
+                    Inclusion::Include => count += 1,
+                    Inclusion::Exclude => (),
+                    Inclusion::Unknown => return None,
+                }
+            } else {
+                return None;
+            }
+        }
+        Some(count)
+    }
+
+    fn produce(&self, log: &LogResult) -> Self::Output {
+        log.players.iter().filter(|p| self.0.filter(p)).count() as u8
+    }
+}
+
+/// A producer that counts the players matching the given filter.
+pub fn player_count(filter: Box<dyn PlayerFilter>) -> Box<dyn Producer<Output = u8>> {
+    Box::new(PlayerCountProducer(filter))
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;