change: more advanced searching and filtering

14 files changed, 674 insertions, 281 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 72b604aa..563b0efb 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.5.0] - Unreleased
+
+### Features
+
+- [#114](https://github.com/ClementTsang/bottom/pull/114): Process state per process (originally in 0.4.0, moved to later).
+
 ## [0.4.0] - Unreleased
 
 ### Features
@@ -13,8 +19,6 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - [#55](https://github.com/ClementTsang/bottom/issues/55): Battery monitoring widget.
 
-- [#114](https://github.com/ClementTsang/bottom/pull/114): Process state per process.
-
 - [#134](https://github.com/ClementTsang/bottom/pull/134): `hjkl` movement to delete dialog (credit to [andys8](https://github.com/andys8)).
 
 - [#59](https://github.com/ClementTsang/bottom/issues/59): `Alt-h` and `Alt-l` to move left/right in query (and rest of the app actually).
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index c616a359..4058e944 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -49,6 +49,9 @@ If you want to help contribute by submitting a PR, by all means, I'm open! In re
 
   - You can check clippy using `cargo +nightly clippy`.
 
+- You may notice that I have fern and log as dependencies; this is mostly for easy debugging via the `debug!()` macro. It writes to the
+  `debug.log` file that will automatically be created if you run in debug mode (so `cargo run`).
+
 And in regards to the pull request process:
 
 - Create a personal fork of the process and PR that, as per the [fork and pull method](https://help.github.com/en/github/collaborating-with-issues-and-pull-requests/about-collaborative-development-models).
diff --git a/Cargo.lock b/Cargo.lock
index 72666d85..ae20694c 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -63,7 +63,7 @@ name = "backtrace"
 version = "0.3.46"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "backtrace-sys 0.1.36 (registry+https://github.com/rust-lang/crates.io-index)",
+ "backtrace-sys 0.1.37 (registry+https://github.com/rust-lang/crates.io-index)",
  "cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.69 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-demangle 0.1.16 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -71,7 +71,7 @@ dependencies = [
 
 [[package]]
 name = "backtrace-sys"
-version = "0.1.36"
+version = "0.1.37"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cc 1.0.52 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -422,7 +422,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro-hack 0.5.15 (registry+https://github.com/rust-lang/crates.io-index)",
  "proc-macro2 1.0.10 (registry+https://github.com/rust-lang/crates.io-index)",
- "quote 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "syn 1.0.18 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -938,7 +938,7 @@ dependencies = [
 
 [[package]]
 name = "quote"
-version = "1.0.3"
+version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 1.0.10 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1063,7 +1063,7 @@ version = "1.0.106"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 1.0.10 (registry+https://github.com/rust-lang/crates.io-index)",
- "quote 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "syn 1.0.18 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -1107,7 +1107,7 @@ version = "1.0.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 1.0.10 (registry+https://github.com/rust-lang/crates.io-index)",
- "quote 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "unicode-xid 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -1191,7 +1191,7 @@ version = "0.5.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 1.0.10 (registry+https://github.com/rust-lang/crates.io-index)",
- "quote 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "syn 1.0.18 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -1310,7 +1310,7 @@ dependencies = [
 "checksum atty 0.2.14 (registry+https://github.com/rust-lang/crates.io-index)" = "d9b39be18770d11421cdb1b9947a45dd3f37e93092cbf377614828a319d5fee8"
 "checksum autocfg 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "f8aac770f1885fd7e387acedd76065302551364496e46b3dd00860b2f8359b9d"
 "checksum backtrace 0.3.46 (registry+https://github.com/rust-lang/crates.io-index)" = "b1e692897359247cc6bb902933361652380af0f1b7651ae5c5013407f30e109e"
-"checksum backtrace-sys 0.1.36 (registry+https://github.com/rust-lang/crates.io-index)" = "78848718ee1255a2485d1309ad9cdecfc2e7d0362dd11c6829364c6b35ae1bc7"
+"checksum backtrace-sys 0.1.37 (registry+https://github.com/rust-lang/crates.io-index)" = "18fbebbe1c9d1f383a9cc7e8ccdb471b91c8d024ee9c2ca5b5346121fe8b4399"
 "checksum base64 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)" = "b41b7ea54a0c9d92199de89e20e58d49f02f8e699814ef3fdf266f6f748d15c7"
 "checksum battery 0.7.5 (registry+https://github.com/rust-lang/crates.io-index)" = "36a698e449024a5d18994a815998bf5e2e4bc1883e35a7d7ba95b6b69ee45907"
 "checksum bitflags 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "cf1de2fe8c75bc145a2f577add951f8134889b4795d47466a54a5c846d691693"
@@ -1403,7 +1403,7 @@ dependencies = [
 "checksum proc-macro-hack 0.5.15 (registry+https://github.com/rust-lang/crates.io-index)" = "0d659fe7c6d27f25e9d80a1a094c223f5246f6a6596453e09d7229bf42750b63"
 "checksum proc-macro-nested 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)" = "8e946095f9d3ed29ec38de908c22f95d9ac008e424c7bcae54c75a79c527c694"
 "checksum proc-macro2 1.0.10 (registry+https://github.com/rust-lang/crates.io-index)" = "df246d292ff63439fea9bc8c0a270bed0e390d5ebd4db4ba15aba81111b5abe3"
-"checksum quote 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)" = "2bdc6c187c65bca4260c9011c9e3132efe4909da44726bad24cf7572ae338d7f"
+"checksum quote 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)" = "4c1f4b0efa5fc5e8ceb705136bfee52cfdb6a4e3509f770b478cd6ed434232a7"
 "checksum raw-cpuid 7.0.3 (registry+https://github.com/rust-lang/crates.io-index)" = "b4a349ca83373cfa5d6dbb66fd76e58b2cca08da71a5f6400de0a0a6a9bceeaf"
 "checksum rayon 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "db6ce3297f9c85e16621bb8cca38a06779ffc31bb8184e1be4bed2be4678a098"
 "checksum rayon-core 1.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "08a89b46efaf957e52b18062fb2f4660f8b8a4dde1807ca002690868ef2c85a9"
diff --git a/Cargo.toml b/Cargo.toml
index 58b5766a..ab5a1a70 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -27,11 +27,9 @@ crossterm = "0.17"
 chrono = "0.4.11"
 clap = "2.33.0"
 dirs = "2.0.2"
-fern = "0.6.0"
 futures = "0.3.4"
 heim = "0.0.10"
 itertools = "0.9.0"
-log = "0.4.8"
 regex = "1.3"
 sysinfo = "0.14"
 toml = "0.5.6"
@@ -42,9 +40,14 @@ serde = {version = "1.0", features = ["derive"] }
 unicode-segmentation = "1.6.0"
 unicode-width = "0.1.7"
 
+# For debugging only...
+fern = "0.6.0"
+log = "0.4.8"
+
 tui = {version = "0.9", features = ["crossterm"], default-features = false }
 # tui = {git = "https://github.com/ClementTsang/tui-rs", features = ["crossterm"], default-features = false }
 
+
 [target.'cfg(windows)'.dependencies]
 winapi = "0.3.8"
 
diff --git a/src/app.rs b/src/app.rs
index de9e8145..ff39f06e 100644
--- a/src/app.rs
+++ b/src/app.rs
@@ -19,6 +19,7 @@ pub mod data_farmer;
 pub mod data_harvester;
 pub mod layout_manager;
 mod process_killer;
+pub mod query;
 pub mod states;
 
 const MAX_SEARCH_LENGTH: usize = 200;
@@ -307,19 +308,6 @@ impl App {
         let is_in_search_widget = self.is_in_search_widget();
         if !self.is_in_dialog() {
             if is_in_search_widget {
-                if let Some(proc_widget_state) = self
-                    .proc_state
-                    .widget_states
-                    .get_mut(&(self.current_widget.widget_id - 1))
-                {
-                    if !proc_widget_state.is_grouped {
-                        if proc_widget_state.process_search_state.is_searching_with_pid {
-                            self.search_with_name();
-                        } else {
-                            self.search_with_pid();
-                        }
-                    }
-                }
             } else if let Some(proc_widget_state) = self
                 .proc_state
                 .widget_states
@@ -327,11 +315,7 @@ impl App {
             {
                 // Toggles process widget grouping state
                 proc_widget_state.is_grouped = !(proc_widget_state.is_grouped);
-                if proc_widget_state.is_grouped {
-                    self.search_with_name();
-                } else {
-                    self.proc_state.force_update = Some(self.current_widget.widget_id);
-                }
+                self.proc_state.force_update = Some(self.current_widget.widget_id);
             }
         }
     }
@@ -387,9 +371,6 @@ impl App {
                             .process_search_state
                             .search_state
                             .is_enabled = true;
-                        if proc_widget_state.is_grouped {
-                            self.search_with_name();
-                        }
                         self.move_widget_selection_down();
                     }
                 }
@@ -426,44 +407,6 @@ impl App {
         }
     }
 
-    pub fn search_with_pid(&mut self) {
-        if !self.is_in_dialog() {
-            if let Some(proc_widget_state) = self
-                .proc_state
-                .widget_states
-                .get_mut(&(self.current_widget.widget_id - 1))
-            {
-                if proc_widget_state
-                    .process_search_state
-                    .search_state
-                    .is_enabled
-                {
-                    proc_widget_state.process_search_state.is_searching_with_pid = true;
-                    self.proc_state.force_update = Some(self.current_widget.widget_id - 1);
-                }
-            }
-        }
-    }
-
-    pub fn search_with_name(&mut self) {
-        if !self.is_in_dialog() {
-            if let Some(proc_widget_state) = self
-                .proc_state
-                .widget_states
-                .get_mut(&(self.current_widget.widget_id - 1))
-            {
-                if proc_widget_state
-                    .process_search_state
-                    .search_state
-                    .is_enabled
-                {
-                    proc_widget_state.process_search_state.is_searching_with_pid = false;
-                    self.proc_state.force_update = Some(self.current_widget.widget_id - 1);
-                }
-            }
-        }
-    }
-
     pub fn toggle_ignore_case(&mut self) {
         let is_in_search_widget = self.is_in_search_widget();
         if let Some(proc_widget_state) = self
@@ -475,7 +418,7 @@ impl App {
                 proc_widget_state
                     .process_search_state
                     .search_toggle_ignore_case();
-                proc_widget_state.update_regex();
+                proc_widget_state.update_query();
                 self.proc_state.force_update = Some(self.current_widget.widget_id - 1);
             }
         }
@@ -492,7 +435,7 @@ impl App {
                 proc_widget_state
                     .process_search_state
                     .search_toggle_whole_word();
-                proc_widget_state.update_regex();
+                proc_widget_state.update_query();
                 self.proc_state.force_update = Some(self.current_widget.widget_id - 1);
             }
         }
@@ -507,7 +450,7 @@ impl App {
         {
             if is_in_search_widget && proc_widget_state.is_search_enabled() {
                 proc_widget_state.process_search_state.search_toggle_regex();
-                proc_widget_state.update_regex();
+                proc_widget_state.update_query();
                 self.proc_state.force_update = Some(self.current_widget.widget_id - 1);
             }
         }
@@ -575,7 +518,7 @@ impl App {
                             true,
                         );
 
-                        proc_widget_state.update_regex();
+                        proc_widget_state.update_query();
                         self.proc_state.force_update = Some(self.current_widget.widget_id - 1);
                     }
                 } else {
@@ -630,24 +573,18 @@ impl App {
                         .search_state
                         .cursor_direction = CursorDirection::LEFT;
 
-                    proc_widget_state.update_regex();
+                    proc_widget_state.update_query();
                     self.proc_state.force_update = Some(self.current_widget.widget_id - 1);
                 }
             }
         }
     }
 
-    pub fn get_current_regex_matcher(
-        &self, widget_id: u64,
-    ) -> &Option<std::result::Result<regex::Regex, regex::Error>> {
-        match self.proc_state.widget_states.get(&widget_id) {
-            Some(proc_widget_state) => {
-                &proc_widget_state
-                    .process_search_state
-                    .search_state
-                    .current_regex
-            }
-            None => &None,
+    pub fn get_process_filter(&self, widget_id: u64) -> &Option<query::Query> {
+        if let Some(process_widget_state) = self.proc_state.widget_states.get(&widget_id) {
+            &process_widget_state.process_search_state.search_state.query
+        } else {
+            &None
         }
     }
 
@@ -872,6 +809,8 @@ impl App {
     }
 
     pub fn start_dd(&mut self) {
+        self.reset_multi_tap_keys();
+
         if let Some(proc_widget_state) = self
             .proc_state
             .widget_states
@@ -885,32 +824,25 @@ impl App {
                 if proc_widget_state.scroll_state.current_scroll_position
                     < corresponding_filtered_process_list.len() as u64
                 {
-                    let current_process = if self.is_grouped(self.current_widget.widget_id) {
-                        let group_pids = &corresponding_filtered_process_list
-                            [proc_widget_state.scroll_state.current_scroll_position as usize]
-                            .group_pids;
-
-                        let mut ret = ("".to_string(), group_pids.clone());
-
-                        for pid in group_pids {
-                            if let Some(process) = self.canvas_data.process_data.get(&pid) {
-                                ret.0 = process.name.clone();
-                                break;
-                            }
+                    let current_process: (String, Vec<u32>);
+                    if self.is_grouped(self.current_widget.widget_id) {
+                        if let Some(process) = &corresponding_filtered_process_list
+                            .get(proc_widget_state.scroll_state.current_scroll_position as usize)
+                        {
+                            current_process = (process.name.to_string(), process.group_pids.clone())
+                        } else {
+                            return;
                         }
-                        ret
                     } else {
                         let process = corresponding_filtered_process_list
                             [proc_widget_state.scroll_state.current_scroll_position as usize]
                             .clone();
-                        (process.name.clone(), vec![process.pid])
+                        current_process = (process.name.clone(), vec![process.pid])
                     };
 
                     self.to_delete_process_list = Some(current_process);
                     self.delete_dialog_state.is_showing_dd = true;
                 }
-
-                self.reset_multi_tap_keys();
             }
         }
     }
@@ -977,7 +909,7 @@ impl App {
                             .char_cursor_position +=
                             UnicodeWidthChar::width(caught_char).unwrap_or(0);
 
-                        proc_widget_state.update_regex();
+                        proc_widget_state.update_query();
                         self.proc_state.force_update = Some(self.current_widget.widget_id - 1);
                         proc_widget_state
                             .process_search_state
diff --git a/src/app/query.rs b/src/app/query.rs
new file mode 100644
index 00000000..cfb8a571
--- /dev/null
+++ b/src/app/query.rs
@@ -0,0 +1,267 @@
+use crate::{
+    data_conversion::ConvertedProcessData,
+    utils::error::{BottomError, Result},
+};
+
+#[derive(Debug)]
+pub struct Query {
+    pub query: And,
+}
+
+impl Query {
+    pub fn process_regexes(
+        &mut self, is_searching_whole_word: bool, is_ignoring_case: bool,
+        is_searching_with_regex: bool,
+    ) -> Result<()> {
+        self.query.process_regexes(
+            is_searching_whole_word,
+            is_ignoring_case,
+            is_searching_with_regex,
+        )
+    }
+
+    pub fn check(&self, process: &ConvertedProcessData) -> bool {
+        self.query.check(process)
+    }
+}
+
+#[derive(Debug)]
+pub struct And {
+    pub lhs: Or,
+    pub rhs: Option<Box<Or>>,
+}
+
+impl And {
+    pub fn process_regexes(
+        &mut self, is_searching_whole_word: bool, is_ignoring_case: bool,
+        is_searching_with_regex: bool,
+    ) -> Result<()> {
+        self.lhs.process_regexes(
+            is_searching_whole_word,
+            is_ignoring_case,
+            is_searching_with_regex,
+        )?;
+        if let Some(rhs) = &mut self.rhs {
+            rhs.process_regexes(
+                is_searching_whole_word,
+                is_ignoring_case,
+                is_searching_with_regex,
+            )?;
+        }
+
+        Ok(())
+    }
+
+    pub fn check(&self, process: &ConvertedProcessData) -> bool {
+        if let Some(rhs) = &self.rhs {
+            self.lhs.check(process) && rhs.check(process)
+        } else {
+            self.lhs.check(process)
+        }
+    }
+}
+
+#[derive(Debug)]
+pub struct Or {
+    pub lhs: Prefix,
+    pub rhs: Option<Box<Prefix>>,
+}
+
+impl Or {
+    pub fn process_regexes(
+        &mut self, is_searching_whole_word: bool, is_ignoring_case: bool,
+        is_searching_with_regex: bool,
+    ) -> Result<()> {
+        self.lhs.process_regexes(
+            is_searching_whole_word,
+            is_ignoring_case,
+            is_searching_with_regex,
+        )?;
+        if let Some(rhs) = &mut self.rhs {
+            rhs.process_regexes(
+                is_searching_whole_word,
+                is_ignoring_case,
+                is_searching_with_regex,
+            )?;
+        }
+
+        Ok(())
+    }
+
+    pub fn check(&self, process: &ConvertedProcessData) -> bool {
+        if let Some(rhs) = &self.rhs {
+            self.lhs.check(process) || rhs.check(process)
+        } else {
+            self.lhs.check(process)
+        }
+    }
+}
+
+#[derive(Debug)]
+pub enum PrefixType {
+    Pid,
+    Cpu,
+    Mem,
+    Rps,
+    Wps,
+    TRead,
+    TWrite,
+    Name,
+    __Nonexhaustive,
+}
+
+impl std::str::FromStr for PrefixType {
+    type Err = BottomError;
+
+    fn from_str(s: &str) -> Result<Self> {
+        use PrefixType::*;
+
+        let lower_case = s.to_lowercase();
+        match lower_case.as_str() {
+            "cpu" => Ok(Cpu),
+            "mem" => Ok(Mem),
+            "r" => Ok(Rps),
+            "w" => Ok(Wps),
+            "read" => Ok(TRead),
+            "write" => Ok(TWrite),
+            "pid" => Ok(Pid),
+            _ => Ok(Name),
+        }
+    }
+}
+
+#[derive(Debug)]
+pub struct Prefix {
+    pub and: Option<Box<And>>,
+    pub regex_prefix: Option<(PrefixType, StringQuery)>,
+    pub compare_prefix: Option<(PrefixType, NumericalQuery)>,
+}
+
+impl Prefix {
+    pub fn process_regexes(
+        &mut self, is_searching_whole_word: bool, is_ignoring_case: bool,
+        is_searching_with_regex: bool,
+    ) -> Result<()> {
+        if let Some(and) = &mut self.and {
+            return and.process_regexes(
+                is_searching_whole_word,
+                is_ignoring_case,
+                is_searching_with_regex,
+            );
+        } else if let Some((prefix_type, query_content)) = &mut self.regex_prefix {
+            if let StringQuery::Value(regex_string) = query_content {
+                match prefix_type {
+                    PrefixType::Pid | PrefixType::Name => {
+                        let escaped_regex: String;
+                        let final_regex_string = &format!(
+                            "{}{}{}{}",
+                            if is_searching_whole_word { "^" } else { "" },
+                            if is_ignoring_case { "(?i)" } else { "" },
+                            if !is_searching_with_regex {
+                                escaped_regex = regex::escape(regex_string);
+                                &escaped_regex
+                            } else {
+                                regex_string
+                            },
+                            if is_searching_whole_word { "$" } else { "" },
+                        );
+
+                        let taken_pwc = self.regex_prefix.take();
+                        if let Some((taken_pt, _)) = taken_pwc {
+                            self.regex_prefix = Some((
+                                taken_pt,
+                                StringQuery::Regex(regex::Regex::new(final_regex_string)?),
+                            ));
+                        }
+                    }
+                    _ => {}
+                }
+            }
+        }
+
+        Ok(())
+    }
+
+    pub fn check(&self, process: &ConvertedProcessData) -> bool {
+        fn matches_condition(condition: &QueryComparison, lhs: f64, rhs: f64) -> bool {
+            match condition {
+                QueryComparison::Equal => lhs == rhs,
+                QueryComparison::Less => lhs < rhs,
+                QueryComparison::Greater => lhs > rhs,
+                QueryComparison::LessOrEqual => lhs <= rhs,
+                QueryComparison::GreaterOrEqual => lhs >= rhs,
+            }
+        }
+
+        if let Some(and) = &self.and {
+            and.check(process)
+        } else if let Some((prefix_type, query_content)) = &self.regex_prefix {
+            if let StringQuery::Regex(r) = query_content {
+                match prefix_type {
+                    PrefixType::Name => r.is_match(process.name.as_str()),
+                    PrefixType::Pid => r.is_match(process.pid.to_string().as_str()),
+                    _ => true,
+                }
+            } else {
+                true
+            }
+        } else if let Some((prefix_type, numerical_query)) = &self.compare_prefix {
+            match prefix_type {
+                PrefixType::Cpu => matches_condition(
+                    &numerical_query.condition,
+                    process.cpu_usage,
+                    numerical_query.value,
+                ),
+                PrefixType::Mem => matches_condition(
+                    &numerical_query.condition,
+                    process.mem_usage,
+                    numerical_query.value,
+                ),
+                PrefixType::Rps => matches_condition(
+                    &numerical_query.condition,
+                    process.rps_f64,
+                    numerical_query.value,
+                ),
+                PrefixType::Wps => matches_condition(
+                    &numerical_query.condition,
+                    process.wps_f64,
+                    numerical_query.value,
+                ),
+                PrefixType::TRead => matches_condition(
+                    &numerical_query.condition,
+                    process.tr_f64,
+                    numerical_query.value,
+                ),
+                PrefixType::TWrite => matches_condition(
+                    &numerical_query.condition,
+                    process.tw_f64,
+                    numerical_query.value,
+                ),
+                _ => true,
+            }
+        } else {
+            true
+        }
+    }
+}
+
+#[derive(Debug)]
+pub enum QueryComparison {
+    Equal,
+    Less,
+    Greater,
+    LessOrEqual,
+    GreaterOrEqual,
+}
+
+#[derive(Debug)]
+pub enum StringQuery {
+    Value(String),
+    Regex(regex::Regex),
+}
+
+#[derive(Debug)]
+pub struct NumericalQuery {
+    pub condition: QueryComparison,
+    pub value: f64,
+}
diff --git a/src/app/states.rs b/src/app/states.rs
index ca181502..825a08fa 100644
--- a/src/app/states.rs
+++ b/src/app/states.rs
@@ -1,10 +1,18 @@
-use std::{collections::HashMap, time::Instant};
+use std::{
+    collections::{HashMap, VecDeque},
+    time::Instant,
+};
 
 use unicode_segmentation::GraphemeCursor;
 
 use tui::widgets::TableState;
 
-use crate::{app::layout_manager::BottomWidgetType, constants, data_harvester::processes};
+use crate::{
+    app::{layout_manager::BottomWidgetType, query::*},
+    constants,
+    data_harvester::processes,
+    utils::error::{BottomError::*, Result},
+};
 
 #[derive(Debug)]
 pub enum ScrollDirection {
@@ -61,7 +69,6 @@ impl Default for AppHelpDialogState {
 pub struct AppSearchState {
     pub is_enabled: bool,
     pub current_search_query: String,
-    pub current_regex: Option<std::result::Result<regex::Regex, regex::Error>>,
     pub is_blank_search: bool,
     pub is_invalid_search: bool,
     pub grapheme_cursor: GraphemeCursor,
@@ -69,6 +76,8 @@ pub struct AppSearchState {
     pub cursor_bar: usize,
     /// This represents the position in terms of CHARACTERS, not graphemes
     pub char_cursor_position: usize,
+    /// The query
+    pub query: Option<Query>,
 }
 
 impl Default for AppSearchState {
@@ -76,13 +85,13 @@ impl Default for AppSearchState {
         AppSearchState {
             is_enabled: false,
             current_search_query: String::default(),
-            current_regex: None,
             is_invalid_search: false,
             is_blank_search: true,
             grapheme_cursor: GraphemeCursor::new(0, 0, true),
             cursor_direction: CursorDirection::RIGHT,
             cursor_bar: 0,
             char_cursor_position: 0,
+            query: None,
         }
     }
 }
@@ -104,7 +113,6 @@ impl AppSearchState {
 /// ProcessSearchState only deals with process' search's current settings and state.
 pub struct ProcessSearchState {
     pub search_state: AppSearchState,
-    pub is_searching_with_pid: bool,
     pub is_ignoring_case: bool,
     pub is_searching_whole_word: bool,
     pub is_searching_with_regex: bool,
@@ -114,7 +122,6 @@ impl Default for ProcessSearchState {
     fn default() -> Self {
         ProcessSearchState {
             search_state: AppSearchState::default(),
-            is_searching_with_pid: false,
             is_ignoring_case: true,
             is_searching_whole_word: false,
             is_searching_with_regex: false,
@@ -188,7 +195,7 @@ impl ProcWidgetState {
         &self.process_search_state.search_state.current_search_query
     }
 
-    pub fn update_regex(&mut self) {
+    pub fn update_query(&mut self) {
         if self
             .process_search_state
             .search_state
@@ -197,39 +204,13 @@ impl ProcWidgetState {
         {
             self.process_search_state.search_state.is_invalid_search = false;
             self.process_search_state.search_state.is_blank_search = true;
+        } else if let Ok(parsed_query) = self.parse_query() {
+            self.process_search_state.search_state.query = Some(parsed_query);
+            self.process_search_state.search_state.is_blank_search = false;
+            self.process_search_state.search_state.is_invalid_search = false;
         } else {
-            let regex_string = &self.process_search_state.search_state.current_search_query;
-            let escaped_regex: String;
-            let final_regex_string = &format!(
-                "{}{}{}{}",
-                if self.process_search_state.is_searching_whole_word {
-                    "^"
-                } else {
-                    ""
-                },
-                if self.process_search_state.is_ignoring_case {
-                    "(?i)"
-                } else {
-                    ""
-                },
-                if !self.process_search_state.is_searching_with_regex {
-                    escaped_regex = regex::escape(regex_string);
-                    &escaped_regex
-                } else {
-                    regex_string
-                },
-                if self.process_search_state.is_searching_whole_word {
-                    "$"
-                } else {
-                    ""
-                },
-            );
-
-            let new_regex = regex::Regex::new(final_regex_string);
             self.process_search_state.search_state.is_blank_search = false;
-            self.process_search_state.search_state.is_invalid_search = new_regex.is_err();
-
-            self.process_search_state.search_state.current_regex = Some(new_regex);
+            self.process_search_state.search_state.is_invalid_search = true;
         }
         self.scroll_state.previous_scroll_position = 0;
         self.scroll_state.current_scroll_position = 0;
@@ -260,6 +241,257 @@ impl ProcWidgetState {
             )
             .unwrap();
     }
+
+    /// The filtering function.  Based on the results of the query.
+    pub fn matches_filter(&self) -> bool {
+        // The way this will have to work is that given a "query" structure, we have
+        // to filter based on it.
+
+        false
+    }
+
+    /// In charge of parsing the given query.
+    /// We are defining the following language for a query (case-insensitive prefixes):
+    ///
+    /// - Process names: No prefix required, can use regex, match word, or case.
+    ///   Enclosing anything, including prefixes, in quotes, means we treat it as an entire process
+    ///   rather than a prefix.
+    /// - PIDs: Use prefix `pid`, can use regex or match word (case is irrelevant).
+    /// - CPU: Use prefix `cpu`, cannot use r/m/c (regex, match word, case).  Can compare.
+    /// - MEM: Use prefix `mem`, cannot use r/m/c.  Can compare.
+    /// - STATE: Use prefix `state`, TODO when we update how state looks in 0.5 probably.
+    /// - Read/s: Use prefix `r`.  Can compare.
+    /// - Write/s: Use prefix `w`.  Can compare.
+    /// - Total read: Use prefix `read`.  Can compare.
+    /// - Total write: Use prefix `write`.  Can compare.
+    ///
+    /// For queries, whitespaces are our delimiters.  We will merge together any adjacent non-prefixed
+    /// or quoted elements after splitting to treat as process names.
+    /// Furthermore, we want to support boolean joiners like AND and OR, and brackets.
+    fn parse_query(&self) -> Result<Query> {
+        fn process_string_to_filter(query: &mut VecDeque<String>) -> Result<Query> {
+            Ok(Query {
+                query: process_and(query)?,
+            })
+        }
+
+        fn process_and(query: &mut VecDeque<String>) -> Result<And> {
+            let mut lhs = process_or(query)?;
+            let mut rhs: Option<Box<Or>> = None;
+
+            while let Some(queue_top) = query.front() {
+                if queue_top.to_lowercase() == "and" {
+                    query.pop_front();
+                    rhs = Some(Box::new(process_or(query)?));
+
+                    if let Some(queue_next) = query.front() {
+                        if queue_next.to_lowercase() == "and" {
+                            // Must merge LHS and RHS
+                            lhs = Or {
+                                lhs: Prefix {
+                                    and: Some(Box::new(And { lhs, rhs })),
+                                    regex_prefix: None,
+                                    compare_prefix: None,
+                                },
+