diff --git a/src/libs/mod.rs b/src/libs/mod.rs
index f4a6baf..e29b260 100644
--- a/src/libs/mod.rs
+++ b/src/libs/mod.rs
@@ -1,36 +1,200 @@
 use std::{
-    io,
-    process::{Child, ChildStdin, ChildStdout, Command},
+    io::{self, BufRead, BufReader, Read, Write},
+    process::{Child, ChildStdin, ChildStdout, Command, Stdio},
+    sync::{Arc, Mutex},
 };
 
+use crate::{
+    parse::{file::File, parse},
+    script::{
+        val_data::{VData, VDataEnum},
+        val_type::VType,
+    },
+};
+
+/*
+Libraries are processes that communicate via stdout/stdin.
+data in stdout is only expected after it was requested via stdin. ignoring this will likely cause issues.
+requests in stdin can be identified via the first byte (ascii char) and end with a \n newline character.
+the identifying ascii chars:
+  i init
+    reply format:
+      two bytes, the first for major and the second for minor version number.
+      the utf8-encoded name of the library followed by a newline
+      the number of lines in the description (0 for no description) as a byte. (more than 255 lines aren't supported)
+      a (optionally markdown-formatted [TODO!]) description of the library; all lines (including the last one) must end with a newline
+      the things you would like to register; one line each unless explicitly stated otherwise; the first byte (char) decides what type to register:
+        f a function: followed by the function signature, i.e. "my_func(string int/float [string]) string/[float int]"
+        x end: indicates that you are done registering things
+  I init 2
+    TODO! (currently nothing)
+    reply should be a single line (only the newline char). If there is data before the newline char, it will be reported as an error and the script will not run.
+  f call a function:
+    followed by the function id byte (0 <= id < #funcs; function ids are assigned in ascending order as they were registered in the reply to "i"
+    and the data for each argument, in order.
+    reply: the data for the returned value
+  x exit
+sending data: (all ints are encoded so that the most significant data is sent FIRST)
+  the first byte (ascii char) identifies the type of data: (exceptions listed first: bools)
+    b false
+    B true
+    1 int
+    2 int as string
+    5 float
+    6 float as string
+    " string (format: ", 64-bit unsigned int indicating string length, so many bytes utf-8)
+
+
+*/
+
+#[derive(Debug)]
 pub struct Lib {
     process: Child,
-    stdin: ChildStdin,
-    stdout: ChildStdout,
+    stdin: Arc<Mutex<ChildStdin>>,
+    stdout: Arc<Mutex<BufReader<ChildStdout>>>,
+    pub registered_fns: Vec<(String, Vec<VType>, VType)>,
 }
 impl Lib {
     pub fn launch(mut exec: Command) -> Result<Self, LaunchError> {
-        let mut handle = match exec.spawn() {
+        let mut handle = match exec
+            .stdin(Stdio::piped())
+            .stdout(Stdio::piped())
+            .stderr(Stdio::inherit())
+            .spawn()
+        {
             Ok(v) => v,
             Err(e) => return Err(LaunchError::CouldNotSpawnProcess(e)),
         };
-        if let (Some(stdin), Some(stdout), stderr) = (
-            handle.stdin.take(),
-            handle.stdout.take(),
-            handle.stderr.take(),
-        ) {
+        if let (Some(mut stdin), Some(stdout)) = (handle.stdin.take(), handle.stdout.take()) {
+            let mut stdout = BufReader::new(stdout);
+            writeln!(stdin, "i").unwrap();
+            let vernum = {
+                let mut vernum = [0, 0];
+                stdout.read_exact(&mut vernum).unwrap();
+                (vernum[0], vernum[1])
+            };
+            let name = stdout.line().unwrap();
+            let name = name.trim();
+            eprintln!("- <<< ADDING LIB: {name} v{}.{} >>> -", vernum.0, vernum.1);
+            let lines_in_desc = stdout.one_byte().unwrap();
+            let mut lines_desc = Vec::with_capacity(lines_in_desc as _);
+            for _ in 0..lines_in_desc {
+                let line = stdout.line().unwrap();
+                let line = line.trim_end_matches('\n');
+                eprintln!("| {line}");
+                lines_desc.push(line.to_string());
+            }
+            let mut registered_fns = vec![];
+            loop {
+                let line = stdout.line().unwrap();
+                match line.chars().next() {
+                    Some('f') => {
+                        let (name, args) = line[1..]
+                            .split_once('(')
+                            .expect("function signature didn't include the ( character.");
+                        let mut fn_signature = File::new(args.to_string());
+                        let mut fn_in = vec![];
+                        loop {
+                            let t = parse::parse_type_adv(&mut fn_signature, true).unwrap();
+                            fn_in.push(t.0);
+                            if t.1 {
+                                break;
+                            }
+                        }
+                        let fn_out = parse::parse_type(&mut fn_signature).unwrap();
+                        eprintln!("Registering function \"{name}\" with args \"{}\" and return type \"{fn_out}\"", &fn_in.iter().fold(String::new(), |mut s, v| { s.push_str(format!(" {}", v).as_str()); s })[1..]);
+                        registered_fns.push((name.to_string(), fn_in, fn_out));
+                    }
+                    _ => break,
+                }
+            }
             Ok(Self {
                 process: handle,
-                stdin,
-                stdout,
+                stdin: Arc::new(Mutex::new(stdin)),
+                stdout: Arc::new(Mutex::new(stdout)),
+                registered_fns,
             })
         } else {
             return Err(LaunchError::NoStdio);
         }
     }
+
+    pub fn run_fn(&self, fnid: usize, args: &Vec<VData>) -> VData {
+        let mut stdin = self.stdin.lock().unwrap();
+        let mut stdout = self.stdout.lock().unwrap();
+        debug_assert!(args.len() == self.registered_fns[fnid].1.len());
+        write!(stdin, "f").unwrap();
+        stdin.write(&[fnid as _]).unwrap();
+        for (_i, arg) in args.iter().enumerate() {
+            data_to_bytes(arg, &mut stdin);
+        }
+        let o = data_from_bytes(&mut stdout).to();
+        o
+    }
 }
 
+#[derive(Debug)]
 pub enum LaunchError {
     NoStdio,
     CouldNotSpawnProcess(io::Error),
 }
+
+trait DirectReader {
+    fn line(&mut self) -> Result<String, io::Error>;
+    fn one_byte(&mut self) -> Result<u8, io::Error>;
+}
+impl<T> DirectReader for T
+where
+    T: BufRead,
+{
+    fn line(&mut self) -> Result<String, io::Error> {
+        let mut buf = String::new();
+        self.read_line(&mut buf)?;
+        Ok(buf)
+    }
+    fn one_byte(&mut self) -> Result<u8, io::Error> {
+        let mut b = [0];
+        self.read(&mut b)?;
+        Ok(b[0])
+    }
+}
+
+fn data_to_bytes(data: &VData, stdin: &mut ChildStdin) {
+    match &data.data {
+        VDataEnum::Bool(false) => write!(stdin, "b").unwrap(),
+        VDataEnum::Bool(true) => write!(stdin, "B").unwrap(),
+        VDataEnum::Int(_) => todo!(),
+        VDataEnum::Float(_) => todo!("floats are not yet implemented for LibFunction calls."),
+        VDataEnum::String(s) => {
+            write!(stdin, "\"").unwrap();
+            stdin.write(&(s.len() as u64).to_be_bytes()).unwrap();
+            stdin.write(s.as_bytes()).unwrap();
+        }
+        VDataEnum::Tuple(_) => todo!(),
+        VDataEnum::List(..) => todo!(),
+        VDataEnum::Function(..) | VDataEnum::Reference(..) | VDataEnum::Thread(..) => {
+            panic!("cannot use functions, references or threads in LibFunctions.")
+        }
+    }
+    stdin.flush().unwrap();
+}
+fn data_from_bytes(stdout: &mut BufReader<ChildStdout>) -> VDataEnum {
+    match stdout.one_byte().unwrap().into() {
+        'b' => VDataEnum::Bool(false),
+        'B' => VDataEnum::Bool(true),
+        '1' | '2' | '5' | '6' => todo!(),
+        '"' => {
+            let mut len_bytes = 0u64;
+            for _ in 0..8 {
+                len_bytes <<= 8;
+                len_bytes |= stdout.one_byte().unwrap() as u64;
+            }
+            let mut buf = Vec::with_capacity(len_bytes as _);
+            for _ in 0..len_bytes {
+                buf.push(stdout.one_byte().unwrap());
+            }
+            VDataEnum::String(String::from_utf8_lossy(&buf).into_owned())
+        }
+        _ => todo!(),
+    }
+}
diff --git a/src/parse/file.rs b/src/parse/file.rs
index 5b13ee0..b4d680e 100644
--- a/src/parse/file.rs
+++ b/src/parse/file.rs
@@ -8,6 +8,7 @@ pub struct File {
     chars: Vec<(usize, char)>,
     pos: FilePosition,
 }
+#[derive(Clone, Copy)]
 pub struct FilePosition {
     current_char_index: usize,
     current_line: usize,
@@ -100,6 +101,17 @@ impl File {
             None => None,
         }
     }
+    pub fn next_line(&mut self) -> String {
+        let mut o = String::new();
+        for ch in self {
+            if ch == '\n' {
+                break;
+            } else {
+                o.push(ch);
+            }
+        }
+        o
+    }
     pub fn peek(&self) -> Option<char> {
         match self.chars.get(self.pos.current_char_index) {
             Some((_, c)) => Some(*c),
diff --git a/src/parse/parse.rs b/src/parse/parse.rs
index a0cc0e5..80b70d2 100644
--- a/src/parse/parse.rs
+++ b/src/parse/parse.rs
@@ -1,10 +1,16 @@
-use crate::script::{
-    block::{
-        to_runnable, to_runnable::ToRunnableError, RScript, SBlock, SFunction, SStatement,
-        SStatementEnum,
+use std::{path::PathBuf, process::Command, sync::Arc};
+
+use crate::{
+    libs,
+    script::{
+        block::{
+            to_runnable::ToRunnableError,
+            to_runnable::{self, GInfo},
+            RScript, SBlock, SFunction, SStatement, SStatementEnum,
+        },
+        val_data::VDataEnum,
+        val_type::{VSingleType, VType},
     },
-    val_data::VDataEnum,
-    val_type::{VSingleType, VType},
 };
 
 use super::file::File;
@@ -28,6 +34,32 @@ impl From<ToRunnableError> for ScriptError {
 pub enum ParseError {}
 
 pub fn parse(file: &mut File) -> Result<RScript, ScriptError> {
+    let mut libs = vec![];
+    loop {
+        file.skip_whitespaces();
+        let pos = file.get_pos().clone();
+        let line = file.next_line();
+        if line.starts_with("lib ") {
+            let path_to_executable: PathBuf = line[4..].into();
+            let mut cmd = Command::new(&path_to_executable);
+            if let Some(parent) = path_to_executable.parent() {
+                cmd.current_dir(parent.clone());
+            }
+            match libs::Lib::launch(cmd) {
+                Ok(lib) => {
+                    libs.push(lib);
+                    eprintln!("Loaded library!");
+                }
+                Err(e) => panic!(
+                    "Unable to load library at {}: {e:?}",
+                    path_to_executable.to_string_lossy().as_ref(),
+                ),
+            }
+        } else {
+            file.set_pos(pos);
+            break;
+        }
+    }
     let func = SFunction::new(
         vec![(
             "args".to_string(),
@@ -36,10 +68,11 @@ pub fn parse(file: &mut File) -> Result<RScript, ScriptError> {
         parse_block_advanced(file, Some(false), true, true, false)?,
     );
     eprintln!();
+    #[cfg(debug_assertions)]
     eprintln!("Parsed: {func}");
     #[cfg(debug_assertions)]
     eprintln!("Parsed: {func:#?}");
-    let run = to_runnable(func)?;
+    let run = to_runnable::to_runnable(func, GInfo::new(Arc::new(libs)))?;
     #[cfg(debug_assertions)]
     eprintln!("Runnable: {run:#?}");
     Ok(run)
@@ -400,13 +433,16 @@ fn parse_function(file: &mut File) -> Result<SFunction, ParseError> {
     Ok(SFunction::new(args, parse_block(file)?))
 }
 
-fn parse_type(file: &mut File) -> Result<VType, ParseError> {
+pub(crate) fn parse_type(file: &mut File) -> Result<VType, ParseError> {
     match parse_type_adv(file, false) {
         Ok((v, _)) => Ok(v),
         Err(e) => Err(e),
     }
 }
-fn parse_type_adv(file: &mut File, in_fn_args: bool) -> Result<(VType, bool), ParseError> {
+pub(crate) fn parse_type_adv(
+    file: &mut File,
+    in_fn_args: bool,
+) -> Result<(VType, bool), ParseError> {
     let mut types = vec![];
     let mut closed_fn_args = false;
     loop {
diff --git a/src/script/block.rs b/src/script/block.rs
index 533c469..da54dd5 100644
--- a/src/script/block.rs
+++ b/src/script/block.rs
@@ -6,7 +6,9 @@ use std::{
     sync::{Arc, Mutex},
 };
 
-use self::to_runnable::ToRunnableError;
+use crate::libs;
+
+use self::to_runnable::{ToRunnableError, GInfo};
 
 use super::{
     builtins::BuiltinFunction,
@@ -84,8 +86,8 @@ fn am<T>(i: T) -> Am<T> {
     Arc::new(Mutex::new(i))
 }
 
-pub fn to_runnable(f: SFunction) -> Result<RScript, ToRunnableError> {
-    to_runnable::to_runnable(f)
+pub fn to_runnable(f: SFunction, ginfo: GInfo) -> Result<RScript, ToRunnableError> {
+    to_runnable::to_runnable(f, ginfo)
 }
 
 pub mod to_runnable {
@@ -95,10 +97,10 @@ pub mod to_runnable {
         sync::Arc,
     };
 
-    use crate::script::{
+    use crate::{script::{
         val_data::VDataEnum,
         val_type::{VSingleType, VType},
-    };
+    }, libs};
 
     use super::{
         BuiltinFunction, RBlock, RFunction, RScript, RStatement, RStatementEnum, SBlock, SFunction,
@@ -151,8 +153,21 @@ pub mod to_runnable {
     }
 
     // Global, shared between all
-    struct GInfo {
+    pub struct GInfo {
         vars: usize,
+        libs: Arc<Vec<libs::Lib>>,
+        lib_fns: HashMap<String, (usize, usize)>,
+    }
+    impl GInfo {
+        pub fn new(libs: Arc<Vec<libs::Lib>>) -> Self {
+            let mut lib_fns = HashMap::new();
+            for (libid, lib) in libs.iter().enumerate() {
+                for (fnid, (name, ..)) in lib.registered_fns.iter().enumerate() {
+                    lib_fns.insert(name.to_string(), (libid, fnid));
+                }
+            }
+            Self { vars: 0, libs, lib_fns, }
+        }
     }
     // Local, used to keep local variables separated
     #[derive(Clone)]
@@ -161,7 +176,7 @@ pub mod to_runnable {
         fns: HashMap<String, Arc<RFunction>>,
     }
 
-    pub fn to_runnable(s: SFunction) -> Result<RScript, ToRunnableError> {
+    pub fn to_runnable(s: SFunction, mut ginfo: GInfo) -> Result<RScript, ToRunnableError> {
         if s.inputs.len() != 1 || s.inputs[0].0 != "args" {
             return Err(ToRunnableError::MainWrongInput);
         }
@@ -172,7 +187,6 @@ pub mod to_runnable {
                 })],
             })
         {}
-        let mut ginfo = GInfo { vars: 0 };
         let func = function(
             &s,
             &mut ginfo,
@@ -181,7 +195,7 @@ pub mod to_runnable {
                 fns: HashMap::new(),
             },
         )?;
-        Ok(RScript::new(func, ginfo.vars)?)
+        Ok(RScript::new(func, ginfo.vars, ginfo.libs)?)
     }
 
     // go over every possible known-type input for the given function, returning all possible RFunctions.
@@ -313,7 +327,22 @@ pub mod to_runnable {
                             todo!("ERR: Builtin function \"{v}\" with wrong args - this isn't a proper error yet, sorry.");
                         }
                     } else {
+                        // LIBRARY FUNCTION?
+                        if let Some((libid, fnid)) = ginfo.lib_fns.get(v) {
+                            let (_name, fn_in, fn_out) = &ginfo.libs[*libid].registered_fns[*fnid];
+                            if fn_in.len() == rargs.len() && fn_in.iter().zip(rargs.iter()).all(|(fn_in, arg)| arg.out().fits_in(fn_in).is_empty()) {
+                                RStatementEnum::LibFunction(*libid, *fnid, rargs, fn_out.clone())
+                            } else {
+                                // TODO! better error here
+                                return Err(if fn_in.len() == rargs.len() {
+                                    todo!("Err: Wrong args for LibFunction \"{v}\".");
+                                } else {
+                                    ToRunnableError::FunctionWrongArgCount(v.to_string(), fn_in.len(), rargs.len())
+                                });
+                            }
+                        } else {
                         return Err(ToRunnableError::UseOfUndefinedFunction(v.clone()));
+                        }
                     }
                 }
             }
@@ -538,10 +567,10 @@ pub struct RBlock {
     statements: Vec<RStatement>,
 }
 impl RBlock {
-    pub fn run(&self, vars: &Vec<Am<VData>>) -> VData {
+    pub fn run(&self, vars: &Vec<Am<VData>>, libs: &Arc<Vec<libs::Lib>>) -> VData {
         let mut last = None;
         for statement in &self.statements {
-            last = Some(statement.run(vars));
+            last = Some(statement.run(vars, libs));
         }
         if let Some(v) = last {
             v
@@ -568,8 +597,8 @@ pub struct RFunction {
     pub block: RBlock,
 }
 impl RFunction {
-    pub fn run(&self, vars: &Vec<Am<VData>>) -> VData {
-        self.block.run(vars)
+    pub fn run(&self, vars: &Vec<Am<VData>>, libs: &Arc<Vec<libs::Lib>>) -> VData {
+        self.block.run(vars, libs)
     }
     pub fn out(&self, input_types: &Vec<VSingleType>) -> VType {
         self.input_output_map
@@ -610,8 +639,8 @@ pub struct RStatement {
     statement: Box<RStatementEnum>,
 }
 impl RStatement {
-    pub fn run(&self, vars: &Vec<Am<VData>>) -> VData {
-        let out = self.statement.run(vars);
+    pub fn run(&self, vars: &Vec<Am<VData>>, libs: &Arc<Vec<libs::Lib>>) -> VData {
+        let out = self.statement.run(vars, libs);
         if let Some(v) = self.output_to {
             *vars[v].lock().unwrap() = out;
             VDataEnum::Tuple(vec![]).to()
@@ -637,6 +666,7 @@ pub enum RStatementEnum {
     Variable(usize, VType, bool), // Arc<Mutex<..>> here, because imagine variable in for loop that is used in a different thread -> we need multiple "same" variables
     FunctionCall(Arc<RFunction>, Vec<RStatement>),
     BuiltinFunction(BuiltinFunction, Vec<RStatement>),
+    LibFunction(usize, usize, Vec<RStatement>, VType),
     Block(RBlock),
     If(RStatement, RStatement, Option<RStatement>),
     While(RStatement),
@@ -646,13 +676,13 @@ pub enum RStatementEnum {
     IndexFixed(RStatement, usize),
 }
 impl RStatementEnum {
-    pub fn run(&self, vars: &Vec<Am<VData>>) -> VData {
+    pub fn run(&self, vars: &Vec<Am<VData>>, libs: &Arc<Vec<libs::Lib>>) -> VData {
         match self {
             Self::Value(v) => v.clone(),
             Self::Tuple(v) => {
                 let mut w = vec![];
                 for v in v {
-                    w.push(v.run(vars));
+                    w.push(v.run(vars, libs));
                 }
                 VDataEnum::Tuple(w).to()
             }
@@ -660,7 +690,7 @@ impl RStatementEnum {
                 let mut w = vec![];
                 let mut out = VType { types: vec![] };
                 for v in v {
-                    let val = v.run(vars);
+                    let val = v.run(vars, libs);
                     out = out | val.out();
                     w.push(val);
                 }
@@ -675,18 +705,20 @@ impl RStatementEnum {
             }
             Self::FunctionCall(func, args) => {
                 for (i, input) in func.inputs.iter().enumerate() {
-                    *vars[*input].lock().unwrap() = args[i].run(vars);
+                    *vars[*input].lock().unwrap() = args[i].run(vars, libs);
                 }
-                func.run(vars)
+                func.run(vars, libs)
             }
-            Self::Block(b) => b.run(vars),
+            Self::BuiltinFunction(v, args) => v.run(args, vars, libs),
+            Self::LibFunction(libid, fnid, args, _) => libs[*libid].run_fn(*fnid, &args.iter().map(|arg| arg.run(vars, libs)).collect()),
+            Self::Block(b) => b.run(vars, libs),
             Self::If(c, t, e) => {
-                if let VDataEnum::Bool(v) = c.run(vars).data {
+                if let VDataEnum::Bool(v) = c.run(vars, libs).data {
                     if v {
-                        t.run(vars)
+                        t.run(vars, libs)
                     } else {
                         if let Some(e) = e {
-                            e.run(vars)
+                            e.run(vars, libs)
                         } else {
                             VDataEnum::Tuple(vec![]).to()
                         }
@@ -697,7 +729,7 @@ impl RStatementEnum {
             }
             Self::While(c) => loop {
                 // While loops blocks can return a bool (false to break from the loop) or a 0-1 length tuple (0-length => continue, 1-length => break with value)
-                match c.run(vars).data {
+                match c.run(vars, libs).data {
                     VDataEnum::Bool(v) => {
                         if !v {
                             break VDataEnum::Tuple(vec![]).to();
@@ -709,11 +741,11 @@ impl RStatementEnum {
                 }
             },
             Self::For(v, c, b) => {
-                let c = c.run(vars);
+                let c = c.run(vars, libs);
                 let mut vars = vars.clone();
                 let mut in_loop = |c| {
                     vars[*v] = Arc::new(Mutex::new(c));
-                    b.run(&vars);
+                    b.run(&vars, libs);
                 };
 
                 match c.data {
@@ -736,14 +768,13 @@ impl RStatementEnum {
                 }
                 VDataEnum::Tuple(vec![]).to()
             }
-            Self::BuiltinFunction(v, args) => v.run(args, vars),
             Self::Switch(switch_on, cases) => {
-                let switch_on = switch_on.run(vars);
+                let switch_on = switch_on.run(vars, libs);
                 let switch_on_type = switch_on.out();
                 let mut out = VDataEnum::Tuple(vec![]).to();
                 for (case_type, case_action) in cases.iter() {
                     if switch_on_type.fits_in(case_type).is_empty() {
-                        out = case_action.run(vars);
+                        out = case_action.run(vars, libs);
                         break;
                     }
                 }
@@ -752,7 +783,7 @@ impl RStatementEnum {
             Self::Match(match_on, cases) => 'm: {
                 for (case_condition, case_action) in cases {
                     // [t] => Some(t), t => Some(t), [] => None
-                    if let Some(v) = match case_condition.run(vars).data {
+                    if let Some(v) = match case_condition.run(vars, libs).data {
                         VDataEnum::Tuple(mut tuple) => tuple.pop(),
                         VDataEnum::Bool(v) => if v { Some(VDataEnum::Bool(v).to()) } else { None },
                         other => Some(other.to()),
@@ -760,14 +791,14 @@ impl RStatementEnum {
                         let og = {
                             std::mem::replace(&mut *vars[*match_on].lock().unwrap(), v)
                         };
-                        let res = case_action.run(vars);
+                        let res = case_action.run(vars, libs);
                         *vars[*match_on].lock().unwrap() = og;
                         break 'm res;
                     }
                 }
                 VDataEnum::Tuple(vec![]).to()
             }
-            Self::IndexFixed(st, i) => st.run(vars).get(*i).unwrap(),
+            Self::IndexFixed(st, i) => st.run(vars, libs).get(*i).unwrap(),
         }
     }
     pub fn out(&self) -> VType {
@@ -796,6 +827,7 @@ impl RStatementEnum {
                 }
             }
             Self::FunctionCall(f, args) => f.out_vt(&args.iter().map(|v| v.out()).collect()),
+            Self::LibFunction(.., out) => out.clone(),
             Self::Block(b) => b.out(),
             Self::If(_, a, b) => {
                 if let Some(b) = b {
@@ -877,13 +909,14 @@ impl RStatementEnum {
 pub struct RScript {
     main: RFunction,
     vars: usize,
+    libs: Arc<Vec<libs::Lib>>,
 }
 impl RScript {
-    fn new(main: RFunction, vars: usize) -> Result<Self, ToRunnableError> {
+    fn new(main: RFunction, vars: usize, libs: Arc<Vec<libs::Lib>>) -> Result<Self, ToRunnableError> {
         if main.inputs.len() != 1 {
             return Err(ToRunnableError::MainWrongInput);
         }
-        Ok(Self { main, vars })
+        Ok(Self { main, vars, libs })
     }
     pub fn run(&self, args: Vec<String>) -> VData {
         let mut vars = Vec::with_capacity(self.vars);
@@ -897,7 +930,7 @@ impl RScript {
         for _i in 1..self.vars {
             vars.push(am(VDataEnum::Tuple(vec![]).to()));
         }
-        self.main.run(&vars)
+        self.main.run(&vars, &self.libs)
     }
 }
 
diff --git a/src/script/builtins.rs b/src/script/builtins.rs
index 8896c8c..7779b9a 100644
--- a/src/script/builtins.rs
+++ b/src/script/builtins.rs
@@ -4,6 +4,8 @@ use std::{
     time::Duration,
 };
 
+use crate::libs;
+
 use super::{
     block::RStatement,
     val_data::{VData, VDataEnum, VDataThreadEnum},
@@ -505,16 +507,21 @@ impl BuiltinFunction {
             },
         }
     }
-    pub fn run(&self, args: &Vec<RStatement>, vars: &Vec<Arc<Mutex<VData>>>) -> VData {
+    pub fn run(
+        &self,
+        args: &Vec<RStatement>,
+        vars: &Vec<Arc<Mutex<VData>>>,
+        libs: &Arc<Vec<libs::Lib>>,
+    ) -> VData {
         match self {
             Self::Assume1 => {
-                if let VDataEnum::Tuple(mut v) = args[0].run(vars).data {
+                if let VDataEnum::Tuple(mut v) = args[0].run(vars, libs).data {
                     v.pop().unwrap()
                 } else {
                     panic!(
                         "ASSUMPTION FAILED: assume1 :: {}",
                         if args.len() > 1 {
-                            if let VDataEnum::String(v) = args[1].run(vars).data {
+                            if let VDataEnum::String(v) = args[1].run(vars, libs).data {
                                 v
                             } else {
                                 String::new()
@@ -526,7 +533,7 @@ impl BuiltinFunction {
                 }
             }
             BuiltinFunction::Print => {
-                if let VDataEnum::String(arg) = args[0].run(vars).data {
+                if let VDataEnum::String(arg) = args[0].run(vars, libs).data {
                     print!("{}", arg);
                     VDataEnum::Tuple(vec![]).to()
                 } else {
@@ -534,7 +541,7 @@ impl BuiltinFunction {
                 }
             }
             BuiltinFunction::Println => {
-                if let VDataEnum::String(arg) = args[0].run(vars).data {
+                if let VDataEnum::String(arg) = args[0].run(vars, libs).data {
                     println!("{}", arg);
                     VDataEnum::Tuple(vec![]).to()
                 } else {
@@ -542,7 +549,7 @@ impl BuiltinFunction {
                 }
             }
             BuiltinFunction::Debug => {
-                println!("{:#?}", args[0].run(vars).data);
+                println!("{:#?}", args[0].run(vars, libs).data);
                 VDataEnum::Tuple(vec![]).to()
             }
             Self::StdinReadLine => {
@@ -551,13 +558,15 @@ impl BuiltinFunction {
                 VDataEnum::String(line.trim_end_matches(['\n', '\r']).to_string()).to()
             }
             BuiltinFunction::ToString => {
-                VDataEnum::String(format!("{}", args[0].run(vars).data)).to()
+                VDataEnum::String(format!("{}", args[0].run(vars, libs).data)).to()
             }
             BuiltinFunction::Format => {
-                if let VDataEnum::String(mut text) = args.first().unwrap().run(vars).data {
+                if let VDataEnum::String(mut text) = args.first().unwrap().run(vars, libs).data {
                     for (i, arg) in args.iter().skip(1).enumerate() {
-                        text =
-                            text.replace(&format!("{{{i}}}"), &format!("{}", arg.run(vars).data));
+                        text = text.replace(
+                            &format!("{{{i}}}"),
+                            &format!("{}", arg.run(vars, libs).data),
+                        );
                     }
                     VDataEnum::String(text).to()
                 } else {
@@ -566,7 +575,7 @@ impl BuiltinFunction {
             }
             BuiltinFunction::ParseInt => {
                 if args.len() == 1 {
-                    if let VDataEnum::String(s) = args[0].run(vars).data {
+                    if let VDataEnum::String(s) = args[0].run(vars, libs).data {
                         if let Ok(s) = s.parse() {
                             VDataEnum::Int(s).to()
                         } else {
@@ -581,7 +590,7 @@ impl BuiltinFunction {
             }
             BuiltinFunction::ParseFloat => {
                 if args.len() == 1 {
-                    if let VDataEnum::String(s) = args[0].run(vars).data {
+                    if let VDataEnum::String(s) = args[0].run(vars, libs).data {
                         if let Ok(s) = s.parse() {
                             VDataEnum::Float(s).to()
                         } else {
@@ -596,15 +605,15 @@ impl BuiltinFunction {
             }
             BuiltinFunction::Run => {
                 if args.len() >= 1 {
-                    if let VDataEnum::Function(f) = args[0].run(vars).data {
+                    if let VDataEnum::Function(f) = args[0].run(vars, libs).data {
                         if f.inputs.len() != args.len() - 1 {
                             unreachable!()
                         }
                         for (i, var) in f.inputs.iter().enumerate() {
-                            let val = args[i + 1].run(vars);
+                            let val = args[i + 1].run(vars, libs);
                             *vars[*var].lock().unwrap() = val;
                         }
-                        f.run(vars)
+                        f.run(vars, libs)
                     } else {
                         unreachable!()
                     }
@@ -614,7 +623,7 @@ impl BuiltinFunction {
             }
             BuiltinFunction::Thread => {
                 if args.len() >= 1 {
-                    if let VDataEnum::Function(f) = args[0].run(vars).data {
+                    if let VDataEnum::Function(f) = args[0].run(vars, libs).data {
                         if f.inputs.len() != args.len() - 1 {
                             unreachable!()
                         }
@@ -622,14 +631,15 @@ impl BuiltinFunction {
                         let mut thread_vars = vars.clone();
                         let mut run_input_types = vec![];
                         for (i, var) in f.inputs.iter().enumerate() {
-                            let val = args[i + 1].run(vars);
+                            let val = args[i + 1].run(vars, libs);
                             run_input_types.push(val.out_single());
                             thread_vars[*var] = Arc::new(Mutex::new(val));
                         }
                         let out_type = f.out(&run_input_types);
+                        let libs = libs.clone();
                         VDataEnum::Thread(
                             VDataThreadEnum::Running(std::thread::spawn(move || {
-                                f.run(&thread_vars)
+                                f.run(&thread_vars, &libs)
                             }))
                             .to(),
                             out_type,
@@ -644,7 +654,7 @@ impl BuiltinFunction {
             }
             BuiltinFunction::Await => {
                 if args.len() == 1 {
-                    if let VDataEnum::Thread(t, _) = args[0].run(vars).data {
+                    if let VDataEnum::Thread(t, _) = args[0].run(vars, libs).data {
                         t.get()
                     } else {
                         unreachable!()
@@ -655,7 +665,7 @@ impl BuiltinFunction {
             }
             BuiltinFunction::Sleep => {
                 if args.len() == 1 {
-                    match args[0].run(vars).data {
+                    match args[0].run(vars, libs).data {
                         VDataEnum::Int(v) => std::thread::sleep(Duration::from_secs(v as _)),
                         VDataEnum::Float(v) => std::thread::sleep(Duration::from_secs_f64(v)),
                         _ => unreachable!(),
@@ -667,7 +677,7 @@ impl BuiltinFunction {
             }
             Self::Exit => {
                 if let Some(s) = args.first() {
-                    if let VDataEnum::Int(v) = s.run(vars).data {
+                    if let VDataEnum::Int(v) = s.run(vars, libs).data {
                         std::process::exit(v as _);
                     } else {
                         std::process::exit(1);
@@ -678,7 +688,7 @@ impl BuiltinFunction {
             }
             Self::FsList => {
                 if args.len() > 0 {
-                    if let VDataEnum::String(path) = args[0].run(vars).data {
+                    if let VDataEnum::String(path) = args[0].run(vars, libs).data {
                         if args.len() > 1 {
                             todo!("fs_list advanced filters")
                         }
@@ -713,7 +723,7 @@ impl BuiltinFunction {
             }
             Self::FsRead => {
                 if args.len() > 0 {
-                    if let VDataEnum::String(path) = args[0].run(vars).data {
+                    if let VDataEnum::String(path) = args[0].run(vars, libs).data {
                         if let Ok(data) = std::fs::read(path) {
                             VDataEnum::List(
                                 VSingleType::Int.into(),
@@ -735,7 +745,7 @@ impl BuiltinFunction {
             Self::FsWrite => {
                 if args.len() > 1 {
                     if let (VDataEnum::String(path), VDataEnum::List(_, data)) =
-                        (args[0].run(vars).data, args[1].run(vars).data)
+                        (args[0].run(vars, libs).data, args[1].run(vars, libs).data)
                     {
                         if let Some(bytes) = vdata_to_bytes(&data) {
                             let file_path: PathBuf = path.into();
@@ -760,7 +770,7 @@ impl BuiltinFunction {
             }
             Self::BytesToString => {
                 if args.len() == 1 {
-                    if let VDataEnum::List(_, byte_data) = args[0].run(vars).data {
+                    if let VDataEnum::List(_, byte_data) = args[0].run(vars, libs).data {
                         if let Some(bytes) = vdata_to_bytes(&byte_data) {
                             match String::from_utf8(bytes) {
                                 Ok(v) => VDataEnum::String(v).to(),
@@ -788,7 +798,7 @@ impl BuiltinFunction {
             }
             Self::StringToBytes => {
                 if args.len() == 1 {
-                    if let VDataEnum::String(s) = args[0].run(vars).data {
+                    if let VDataEnum::String(s) = args[0].run(vars, libs).data {
                         VDataEnum::List(
                             VSingleType::Int.into(),
                             s.bytes().map(|v| VDataEnum::Int(v as isize).to()).collect(),
@@ -803,10 +813,10 @@ impl BuiltinFunction {
             }
             Self::RunCommand | Self::RunCommandGetBytes => {
                 if args.len() > 0 {
-                    if let VDataEnum::String(s) = args[0].run(vars).data {
+                    if let VDataEnum::String(s) = args[0].run(vars, libs).data {
                         let mut command = std::process::Command::new(s);
                         if args.len() > 1 {
-                            if let VDataEnum::List(_, args) = args[1].run(vars).data {
+                            if let VDataEnum::List(_, args) = args[1].run(vars, libs).data {
                                 for arg in args {
                                     if let VDataEnum::String(v) = arg.data {
                                         command.arg(v);
@@ -865,7 +875,7 @@ impl BuiltinFunction {
             }
             Self::Add => {
                 if args.len() == 2 {
-                    match (args[0].run(vars).data, args[1].run(vars).data) {
+                    match (args[0].run(vars, libs).data, args[1].run(vars, libs).data) {
                         (VDataEnum::Int(a), VDataEnum::Int(b)) => VDataEnum::Int(a + b).to(),
                         (VDataEnum::Int(a), VDataEnum::Float(b)) => {
                             VDataEnum::Float(a as f64 + b).to()
@@ -882,7 +892,7 @@ impl BuiltinFunction {
             }
             Self::Sub => {
                 if args.len() == 2 {
-                    match (args[0].run(vars).data, args[1].run(vars).data) {
+                    match (args[0].run(vars, libs).data, args[1].run(vars, libs).data) {
                         (VDataEnum::Int(a), VDataEnum::Int(b)) => VDataEnum::Int(a - b).to(),
                         (VDataEnum::Int(a), VDataEnum::Float(b)) => {
                             VDataEnum::Float(a as f64 - b).to()
@@ -899,7 +909,7 @@ impl BuiltinFunction {
             }
             Self::Mul => {
                 if args.len() == 2 {
-                    match (args[0].run(vars).data, args[1].run(vars).data) {
+                    match (args[0].run(vars, libs).data, args[1].run(vars, libs).data) {
                         (VDataEnum::Int(a), VDataEnum::Int(b)) => VDataEnum::Int(a * b).to(),
                         (VDataEnum::Int(a), VDataEnum::Float(b)) => {
                             VDataEnum::Float(a as f64 * b).to()
@@ -916,7 +926,7 @@ impl BuiltinFunction {
             }
             Self::Div => {
                 if args.len() == 2 {
-                    match (args[0].run(vars).data, args[1].run(vars).data) {
+                    match (args[0].run(vars, libs).data, args[1].run(vars, libs).data) {
                         (VDataEnum::Int(a), VDataEnum::Int(b)) => VDataEnum::Int(a / b).to(),
                         (VDataEnum::Int(a), VDataEnum::Float(b)) => {
                             VDataEnum::Float(a as f64 / b).to()
@@ -933,7 +943,7 @@ impl BuiltinFunction {
             }
             Self::Mod => {
                 if args.len() == 2 {
-                    match (args[0].run(vars).data, args[1].run(vars).data) {
+                    match (args[0].run(vars, libs).data, args[1].run(vars, libs).data) {
                         (VDataEnum::Int(a), VDataEnum::Int(b)) => VDataEnum::Int(a % b).to(),
                         (VDataEnum::Int(a), VDataEnum::Float(b)) => {
                             VDataEnum::Float(a as f64 % b).to()
@@ -950,7 +960,7 @@ impl BuiltinFunction {
             }
             Self::Pow => {
                 if args.len() == 2 {
-                    match (args[0].run(vars).data, args[1].run(vars).data) {
+                    match (args[0].run(vars, libs).data, args[1].run(vars, libs).data) {
                         (VDataEnum::Int(a), VDataEnum::Int(b)) => VDataEnum::Int(if b == 0 {
                             1
                         } else if b > 0 {
@@ -976,7 +986,7 @@ impl BuiltinFunction {
             }
             Self::Eq => {
                 if args.len() == 2 {
-                    match (args[0].run(vars).data, args[1].run(vars).data) {
+                    match (args[0].run(vars, libs).data, args[1].run(vars, libs).data) {
                         (VDataEnum::Int(a), VDataEnum::Int(b)) => VDataEnum::Bool(a == b).to(),
                         (VDataEnum::Int(a), VDataEnum::Float(b)) => {
                             VDataEnum::Bool(a as f64 == b).to()
@@ -996,7 +1006,7 @@ impl BuiltinFunction {
             }
             Self::Gt => {
                 if args.len() == 2 {
-                    match (args[0].run(vars).data, args[1].run(vars).data) {
+                    match (args[0].run(vars, libs).data, args[1].run(vars, libs).data) {
                         (VDataEnum::Int(a), VDataEnum::Int(b)) => VDataEnum::Bool(a > b).to(),
                         (VDataEnum::Int(a), VDataEnum::Float(b)) => {
                             VDataEnum::Bool(a as f64 > b).to()
@@ -1013,7 +1023,7 @@ impl BuiltinFunction {
             }
             Self::Lt => {
                 if args.len() == 2 {
-                    match (args[0].run(vars).data, args[1].run(vars).data) {
+                    match (args[0].run(vars, libs).data, args[1].run(vars, libs).data) {
                         (VDataEnum::Int(a), VDataEnum::Int(b)) => VDataEnum::Bool(a < b).to(),
                         (VDataEnum::Int(a), VDataEnum::Float(b)) => {
                             VDataEnum::Bool((a as f64) < b).to()
@@ -1030,7 +1040,7 @@ impl BuiltinFunction {
             }
             Self::Gtoe => {
                 if args.len() == 2 {
-                    match (args[0].run(vars).data, args[1].run(vars).data) {
+                    match (args[0].run(vars, libs).data, args[1].run(vars, libs).data) {
                         (VDataEnum::Int(a), VDataEnum::Int(b)) => VDataEnum::Bool(a >= b).to(),
                         (VDataEnum::Int(a), VDataEnum::Float(b)) => {
                             VDataEnum::Bool(a as f64 >= b).to()
@@ -1047,7 +1057,7 @@ impl BuiltinFunction {
             }
             Self::Ltoe => {
                 if args.len() == 2 {
-                    match (args[0].run(vars).data, args[1].run(vars).data) {
+                    match (args[0].run(vars, libs).data, args[1].run(vars, libs).data) {
                         (VDataEnum::Int(a), VDataEnum::Int(b)) => VDataEnum::Bool(a <= b).to(),
                         (VDataEnum::Int(a), VDataEnum::Float(b)) => {
                             VDataEnum::Bool(a as f64 <= b).to()
@@ -1064,7 +1074,7 @@ impl BuiltinFunction {
             }
             Self::Min => {
                 if args.len() == 2 {
-                    match (args[0].run(vars).data, args[1].run(vars).data) {
+                    match (args[0].run(vars, libs).data, args[1].run(vars, libs).data) {
                         (VDataEnum::Int(a), VDataEnum::Int(b)) => VDataEnum::Int(a.min(b)).to(),
                         (VDataEnum::Int(a), VDataEnum::Float(b)) => {
                             VDataEnum::Float((a as f64).min(b)).to()
@@ -1083,7 +1093,7 @@ impl BuiltinFunction {
             }
             Self::Max => {
                 if args.len() == 2 {
-                    match (args[0].run(vars).data, args[1].run(vars).data) {
+                    match (args[0].run(vars, libs).data, args[1].run(vars, libs).data) {
                         (VDataEnum::Int(a), VDataEnum::Int(b)) => VDataEnum::Int(a.max(b)).to(),
                         (VDataEnum::Int(a), VDataEnum::Float(b)) => {
                             VDataEnum::Float((a as f64).max(b)).to()
@@ -1102,9 +1112,9 @@ impl BuiltinFunction {
             }
             Self::Push => {
                 if args.len() == 2 {
-                    if let VDataEnum::Reference(v) = args[0].run(vars).data {
+                    if let VDataEnum::Reference(v) = args[0].run(vars, libs).data {
                         if let VDataEnum::List(_, v) = &mut v.lock().unwrap().data {
-                            v.push(args[1].run(vars));
+                            v.push(args[1].run(vars, libs));
                         }
                         VDataEnum::Tuple(vec![]).to()
                     } else {
@@ -1117,10 +1127,10 @@ impl BuiltinFunction {
             Self::Insert => {
                 if args.len() == 3 {
                     if let (VDataEnum::Reference(v), VDataEnum::Int(i)) =
-                        (args[0].run(vars).data, args[2].run(vars).data)
+                        (args[0].run(vars, libs).data, args[2].run(vars, libs).data)
                     {
                         if let VDataEnum::List(_, v) = &mut v.lock().unwrap().data {
-                            v.insert(i as _, args[1].run(vars));
+                            v.insert(i as _, args[1].run(vars, libs));
                         }
                         VDataEnum::Tuple(vec![]).to()
                     } else {
@@ -1132,7 +1142,7 @@ impl BuiltinFunction {
             }
             Self::Pop => {
                 if args.len() == 1 {
-                    if let VDataEnum::Reference(v) = args[0].run(vars).data {
+                    if let VDataEnum::Reference(v) = args[0].run(vars, libs).data {
                         if let VDataEnum::List(_, v) = &mut v.lock().unwrap().data {
                             v.pop().unwrap_or_else(|| VDataEnum::Tuple(vec![]).to())
                         } else {
@@ -1148,7 +1158,7 @@ impl BuiltinFunction {
             Self::Remove => {
                 if args.len() == 2 {
                     if let (VDataEnum::Reference(v), VDataEnum::Int(i)) =
-                        (args[0].run(vars).data, args[1].run(vars).data)
+                        (args[0].run(vars, libs).data, args[1].run(vars, libs).data)
                     {
                         if let VDataEnum::List(_, v) = &mut v.lock().unwrap().data {
                             if v.len() > i as _ && i >= 0 {
@@ -1169,19 +1179,21 @@ impl BuiltinFunction {
             Self::Get => {
                 if args.len() == 2 {
                     if let (VDataEnum::Reference(v), VDataEnum::Int(i)) =
-                        (args[0].run(vars).data, args[1].run(vars).data)
+                        (args[0].run(vars, libs).data, args[1].run(vars, libs).data)
                     {
-                        if let VDataEnum::List(_, v) = &mut v.lock().unwrap().data {
+                        if let VDataEnum::List(_, v) | VDataEnum::Tuple(v) =
+                            &mut v.lock().unwrap().data
+                        {
                             if i >= 0 {
                                 match v.get(i as usize) {
-                                    Some(v) => v.clone(),
+                                    Some(v) => VDataEnum::Tuple(vec![v.clone()]).to(),
                                     None => VDataEnum::Tuple(vec![]).to(),
                                 }
                             } else {
                                 VDataEnum::Tuple(vec![]).to()
                             }
                         } else {
-                            unreachable!("get: not a list")
+                            unreachable!("get: not a list/tuple")
                         }
                     } else {
                         unreachable!("get: not a reference and index")
@@ -1192,7 +1204,7 @@ impl BuiltinFunction {
             }
             Self::Len => {
                 if args.len() == 1 {
-                    VDataEnum::Int(match args[0].run(vars).data {
+                    VDataEnum::Int(match args[0].run(vars, libs).data {
                         VDataEnum::String(v) => v.len(),
                         VDataEnum::Tuple(v) => v.len(),
                         VDataEnum::List(_, v) => v.len(),
@@ -1205,8 +1217,8 @@ impl BuiltinFunction {
             }
             Self::Contains => {
                 if args.len() == 2 {
-                    if let VDataEnum::String(a1) = args[0].run(vars).data {
-                        if let VDataEnum::String(a2) = args[1].run(vars).data {
+                    if let VDataEnum::String(a1) = args[0].run(vars, libs).data {
+                        if let VDataEnum::String(a2) = args[1].run(vars, libs).data {
                             VDataEnum::Bool(a1.contains(a2.as_str())).to()
                         } else {
                             unreachable!()
@@ -1220,8 +1232,8 @@ impl BuiltinFunction {
             }
             Self::StartsWith => {
                 if args.len() == 2 {
-                    if let VDataEnum::String(a1) = args[0].run(vars).data {
-                        if let VDataEnum::String(a2) = args[1].run(vars).data {
+                    if let VDataEnum::String(a1) = args[0].run(vars, libs).data {
+                        if let VDataEnum::String(a2) = args[1].run(vars, libs).data {
                             VDataEnum::Bool(a1.starts_with(a2.as_str())).to()
                         } else {
                             unreachable!()
@@ -1235,8 +1247,8 @@ impl BuiltinFunction {
             }
             Self::EndsWith => {
                 if args.len() == 2 {
-                    if let VDataEnum::String(a1) = args[0].run(vars).data {
-                        if let VDataEnum::String(a2) = args[1].run(vars).data {
+                    if let VDataEnum::String(a1) = args[0].run(vars, libs).data {
+                        if let VDataEnum::String(a2) = args[1].run(vars, libs).data {
                             VDataEnum::Bool(a1.ends_with(a2.as_str())).to()
                         } else {
                             unreachable!()
@@ -1250,7 +1262,7 @@ impl BuiltinFunction {
             }
             Self::Trim => {
                 if args.len() == 1 {
-                    if let VDataEnum::String(a) = args[0].run(vars).data {
+                    if let VDataEnum::String(a) = args[0].run(vars, libs).data {
                         VDataEnum::String(a.trim().to_string()).to()
                     } else {
                         unreachable!()
@@ -1261,17 +1273,17 @@ impl BuiltinFunction {
             }
             Self::Substring => {
                 if args.len() >= 2 {
-                    if let VDataEnum::String(a) = args[0].run(vars).data {
+                    if let VDataEnum::String(a) = args[0].run(vars, libs).data {
                         if args.len() > 3 {
                             unreachable!()
                         }
-                        let left = if let VDataEnum::Int(left) = args[1].run(vars).data {
+                        let left = if let VDataEnum::Int(left) = args[1].run(vars, libs).data {
                             left
                         } else {
                             unreachable!()
                         };
                         let len = if args.len() == 3 {
-                            if let VDataEnum::Int(len) = args[2].run(vars).data {
+                            if let VDataEnum::Int(len) = args[2].run(vars, libs).data {
                                 Some(len)
                             } else {
                                 unreachable!()
@@ -1300,7 +1312,7 @@ impl BuiltinFunction {
             Self::Regex => {
                 if args.len() == 2 {
                     if let (VDataEnum::String(a), VDataEnum::String(regex)) =
-                        (args[0].run(vars).data, args[1].run(vars).data)
+                        (args[0].run(vars, libs).data, args[1].run(vars, libs).data)
                     {
                         match regex::Regex::new(regex.as_str()) {
                             Ok(regex) => {