diff --git a/Cargo.lock b/Cargo.lock
index fd5c6d0..d3e1fa3 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2,26 +2,118 @@
 # It is not intended for manual editing.
 version = 3
 
+[[package]]
+name = "bitflags"
+version = "2.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ed570934406eb16438a4e976b1b4500774099c13b8cb96eec99f620f05090ddf"
+
+[[package]]
+name = "cfg-if"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
+
+[[package]]
+name = "colored"
+version = "2.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cbf2150cce219b664a8a70df7a1f933836724b503f8a413af9365b4dcc4d90b8"
+dependencies = [
+ "lazy_static",
+ "windows-sys 0.48.0",
+]
+
+[[package]]
+name = "errno"
+version = "0.3.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a258e46cdc063eb8519c00b9fc845fc47bcfca4130e2f08e88665ceda8474245"
+dependencies = [
+ "libc",
+ "windows-sys 0.52.0",
+]
+
+[[package]]
+name = "hermit-abi"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d77f7ec81a6d05a3abb01ab6eb7590f6083d08449fe5a1c8b1e620283546ccb7"
+
+[[package]]
+name = "is-terminal"
+version = "0.4.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0bad00257d07be169d870ab665980b06cdb366d792ad690bf2e76876dc503455"
+dependencies = [
+ "hermit-abi",
+ "rustix",
+ "windows-sys 0.52.0",
+]
+
 [[package]]
 name = "kabel"
 version = "0.1.0"
 dependencies = [
+ "is-terminal",
  "libkabel",
+ "tracing-subscriber",
 ]
 
+[[package]]
+name = "lazy_static"
+version = "1.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
+
+[[package]]
+name = "libc"
+version = "0.2.152"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "13e3bf6590cbc649f4d1a3eefc9d5d6eb746f5200ffb04e5e142700b8faa56e7"
+
 [[package]]
 name = "libkabel"
 version = "0.1.0"
 dependencies = [
+ "colored",
  "tracing",
 ]
 
+[[package]]
+name = "linux-raw-sys"
+version = "0.4.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c4cd1a83af159aa67994778be9070f0ae1bd732942279cabb14f86f986a21456"
+
+[[package]]
+name = "log"
+version = "0.4.20"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b5e6163cb8c49088c2c36f57875e58ccd8c87c7427f7fbd50ea6710b2f3f2e8f"
+
+[[package]]
+name = "nu-ansi-term"
+version = "0.46.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "77a8165726e8236064dbb45459242600304b42a5ea24ee2948e18e023bf7ba84"
+dependencies = [
+ "overload",
+ "winapi",
+]
+
 [[package]]
 name = "once_cell"
 version = "1.19.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3fdb12b2476b595f9358c5161aa467c2438859caa136dec86c26fdd2efe17b92"
 
+[[package]]
+name = "overload"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b15813163c1d831bf4a13c3610c05c0d03b39feb07f7e09fa234dac9b15aaf39"
+
 [[package]]
 name = "pin-project-lite"
 version = "0.2.13"
@@ -46,6 +138,34 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "rustix"
+version = "0.38.30"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "322394588aaf33c24007e8bb3238ee3e4c5c09c084ab32bc73890b99ff326bca"
+dependencies = [
+ "bitflags",
+ "errno",
+ "libc",
+ "linux-raw-sys",
+ "windows-sys 0.52.0",
+]
+
+[[package]]
+name = "sharded-slab"
+version = "0.1.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f40ca3c46823713e0d4209592e8d6e826aa57e928f09752619fc696c499637f6"
+dependencies = [
+ "lazy_static",
+]
+
+[[package]]
+name = "smallvec"
+version = "1.12.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2593d31f82ead8df961d8bd23a64c2ccf2eb5dd34b0a34bfb4dd54011c72009e"
+
 [[package]]
 name = "syn"
 version = "2.0.48"
@@ -57,6 +177,16 @@ dependencies = [
  "unicode-ident",
 ]
 
+[[package]]
+name = "thread_local"
+version = "1.1.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3fdd6f064ccff2d6567adcb3873ca630700f00b5ad3f060c25b5dcfd9a4ce152"
+dependencies = [
+ "cfg-if",
+ "once_cell",
+]
+
 [[package]]
 name = "tracing"
 version = "0.1.40"
@@ -86,6 +216,32 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c06d3da6113f116aaee68e4d601191614c9053067f9ab7f6edbcb161237daa54"
 dependencies = [
  "once_cell",
+ "valuable",
+]
+
+[[package]]
+name = "tracing-log"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ee855f1f400bd0e5c02d150ae5de3840039a3f54b025156404e34c23c03f47c3"
+dependencies = [
+ "log",
+ "once_cell",
+ "tracing-core",
+]
+
+[[package]]
+name = "tracing-subscriber"
+version = "0.3.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ad0f048c97dbd9faa9b7df56362b8ebcaa52adb06b498c050d2f4e32f90a7a8b"
+dependencies = [
+ "nu-ansi-term",
+ "sharded-slab",
+ "smallvec",
+ "thread_local",
+ "tracing-core",
+ "tracing-log",
 ]
 
 [[package]]
@@ -93,3 +249,163 @@ name = "unicode-ident"
 version = "1.0.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3354b9ac3fae1ff6755cb6db53683adb661634f67557942dea4facebec0fee4b"
+
+[[package]]
+name = "valuable"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "830b7e5d4d90034032940e4ace0d9a9a057e7a45cd94e6c007832e39edb82f6d"
+
+[[package]]
+name = "winapi"
+version = "0.3.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5c839a674fcd7a98952e593242ea400abe93992746761e38641405d28b00f419"
+dependencies = [
+ "winapi-i686-pc-windows-gnu",
+ "winapi-x86_64-pc-windows-gnu",
+]
+
+[[package]]
+name = "winapi-i686-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
+
+[[package]]
+name = "winapi-x86_64-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
+
+[[package]]
+name = "windows-sys"
+version = "0.48.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "677d2418bec65e3338edb076e806bc1ec15693c5d0104683f2efe857f61056a9"
+dependencies = [
+ "windows-targets 0.48.5",
+]
+
+[[package]]
+name = "windows-sys"
+version = "0.52.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "282be5f36a8ce781fad8c8ae18fa3f9beff57ec1b52cb3de0789201425d9a33d"
+dependencies = [
+ "windows-targets 0.52.0",
+]
+
+[[package]]
+name = "windows-targets"
+version = "0.48.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9a2fa6e2155d7247be68c096456083145c183cbbbc2764150dda45a87197940c"
+dependencies = [
+ "windows_aarch64_gnullvm 0.48.5",
+ "windows_aarch64_msvc 0.48.5",
+ "windows_i686_gnu 0.48.5",
+ "windows_i686_msvc 0.48.5",
+ "windows_x86_64_gnu 0.48.5",
+ "windows_x86_64_gnullvm 0.48.5",
+ "windows_x86_64_msvc 0.48.5",
+]
+
+[[package]]
+name = "windows-targets"
+version = "0.52.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8a18201040b24831fbb9e4eb208f8892e1f50a37feb53cc7ff887feb8f50e7cd"
+dependencies = [
+ "windows_aarch64_gnullvm 0.52.0",
+ "windows_aarch64_msvc 0.52.0",
+ "windows_i686_gnu 0.52.0",
+ "windows_i686_msvc 0.52.0",
+ "windows_x86_64_gnu 0.52.0",
+ "windows_x86_64_gnullvm 0.52.0",
+ "windows_x86_64_msvc 0.52.0",
+]
+
+[[package]]
+name = "windows_aarch64_gnullvm"
+version = "0.48.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2b38e32f0abccf9987a4e3079dfb67dcd799fb61361e53e2882c3cbaf0d905d8"
+
+[[package]]
+name = "windows_aarch64_gnullvm"
+version = "0.52.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cb7764e35d4db8a7921e09562a0304bf2f93e0a51bfccee0bd0bb0b666b015ea"
+
+[[package]]
+name = "windows_aarch64_msvc"
+version = "0.48.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dc35310971f3b2dbbf3f0690a219f40e2d9afcf64f9ab7cc1be722937c26b4bc"
+
+[[package]]
+name = "windows_aarch64_msvc"
+version = "0.52.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bbaa0368d4f1d2aaefc55b6fcfee13f41544ddf36801e793edbbfd7d7df075ef"
+
+[[package]]
+name = "windows_i686_gnu"
+version = "0.48.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a75915e7def60c94dcef72200b9a8e58e5091744960da64ec734a6c6e9b3743e"
+
+[[package]]
+name = "windows_i686_gnu"
+version = "0.52.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a28637cb1fa3560a16915793afb20081aba2c92ee8af57b4d5f28e4b3e7df313"
+
+[[package]]
+name = "windows_i686_msvc"
+version = "0.48.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8f55c233f70c4b27f66c523580f78f1004e8b5a8b659e05a4eb49d4166cca406"
+
+[[package]]
+name = "windows_i686_msvc"
+version = "0.52.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ffe5e8e31046ce6230cc7215707b816e339ff4d4d67c65dffa206fd0f7aa7b9a"
+
+[[package]]
+name = "windows_x86_64_gnu"
+version = "0.48.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "53d40abd2583d23e4718fddf1ebec84dbff8381c07cae67ff7768bbf19c6718e"
+
+[[package]]
+name = "windows_x86_64_gnu"
+version = "0.52.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3d6fa32db2bc4a2f5abeacf2b69f7992cd09dca97498da74a151a3132c26befd"
+
+[[package]]
+name = "windows_x86_64_gnullvm"
+version = "0.48.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0b7b52767868a23d5bab768e390dc5f5c55825b6d30b86c844ff2dc7414044cc"
+
+[[package]]
+name = "windows_x86_64_gnullvm"
+version = "0.52.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1a657e1e9d3f514745a572a6846d3c7aa7dbe1658c056ed9c3344c4109a6949e"
+
+[[package]]
+name = "windows_x86_64_msvc"
+version = "0.48.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ed94fce61571a4006852b7389a063ab983c02eb1bb37b47f8272ce92d06d9538"
+
+[[package]]
+name = "windows_x86_64_msvc"
+version = "0.52.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dff9641d1cd4be8d1a070daf9e3773c5f67e78b4d9d42263020c057706765c04"
diff --git a/kabel/Cargo.toml b/kabel/Cargo.toml
index 070f3fe..9cfbb8f 100644
--- a/kabel/Cargo.toml
+++ b/kabel/Cargo.toml
@@ -8,4 +8,6 @@ description = "A dead-simple scripting language for use in games"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-libkabel = { version = "0.1", path = "../libkabel" }
\ No newline at end of file
+libkabel = { version = "0.1", path = "../libkabel", features = ["pretty-emitter"] }
+is-terminal = "0.4"
+tracing-subscriber = "0.3"
\ No newline at end of file
diff --git a/kabel/src/main.rs b/kabel/src/main.rs
index 7d8b432..f1fe6d6 100644
--- a/kabel/src/main.rs
+++ b/kabel/src/main.rs
@@ -2,7 +2,9 @@ use std::env;
 use std::error::Error;
 use std::fs::File;
 use std::io::{self, Read};
-use libkabel::lexutil::Token;
+use libkabel::diagnostics::emitters::Emitter;
+use libkabel::error::KError;
+use libkabel::lexer::token::Token;
 
 fn main() -> Result<(), Box<dyn Error>> {
     let argv: Vec<String> = env::args().collect();
@@ -26,17 +28,28 @@ fn main() -> Result<(), Box<dyn Error>> {
         Ok(fd) => fd,
     };
 
+    tracing_subscriber::fmt::init();
+
     let mut text_source = String::new();
     source_fd.read_to_string(&mut text_source)?;
 
     // Lex!
     let lexed: Vec<Token> = match libkabel::lexer::lexer(&text_source) {
         Err(e) => {
-            eprintln!("Lexer fail with {}", e);
+            match e {
+                KError::InternalError(e) => {
+                    eprintln!("ICE! Please report this to the kabel developers, along with what you were doing: {:?}", e);
+                }
+                KError::UserError(diags) => {
+                    eprintln!("{}", libkabel::diagnostics::emitters::basic::BasicEmitter::emit(diags, text_source));
+                }
+            }
             std::process::exit(1);
         }
         Ok(lexed) => lexed,
     };
 
+    println!("{:#?}", lexed);
+
     Ok(())
 }
diff --git a/libkabel/Cargo.toml b/libkabel/Cargo.toml
index 135642e..1325bc5 100644
--- a/libkabel/Cargo.toml
+++ b/libkabel/Cargo.toml
@@ -6,4 +6,9 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-tracing = "0.1"
\ No newline at end of file
+tracing = "0.1"
+colored = { version = "2", optional = true }
+
+[features]
+default = []
+pretty-emitter = ["colored"]
\ No newline at end of file
diff --git a/libkabel/src/diagnostics/emitters/basic.rs b/libkabel/src/diagnostics/emitters/basic.rs
new file mode 100644
index 0000000..50c4e60
--- /dev/null
+++ b/libkabel/src/diagnostics/emitters/basic.rs
@@ -0,0 +1,19 @@
+use crate::diagnostics::Diagnostic;
+use crate::diagnostics::emitters::Emitter;
+use std::fmt::Write;
+
+pub struct BasicEmitter;
+
+impl Emitter for BasicEmitter {
+    type Output = String;
+
+    fn emit(diag: Vec<Diagnostic>, _source: String) -> Self::Output {
+        let mut output = String::new();
+
+        for msg in diag {
+            writeln!(output, "{:?}", msg).unwrap();
+        }
+
+        output
+    }
+}
\ No newline at end of file
diff --git a/libkabel/src/diagnostics/emitters/mod.rs b/libkabel/src/diagnostics/emitters/mod.rs
new file mode 100644
index 0000000..0643195
--- /dev/null
+++ b/libkabel/src/diagnostics/emitters/mod.rs
@@ -0,0 +1,10 @@
+use crate::diagnostics::Diagnostic;
+
+pub mod basic;
+#[cfg(feature = "pretty-emitter")]
+pub mod pretty;
+
+pub trait Emitter {
+    type Output;
+    fn emit(diag: Vec<Diagnostic>, source: String) -> Self::Output;
+}
\ No newline at end of file
diff --git a/libkabel/src/diagnostics/emitters/pretty.rs b/libkabel/src/diagnostics/emitters/pretty.rs
new file mode 100644
index 0000000..e69de29
diff --git a/libkabel/src/diagnostics/mod.rs b/libkabel/src/diagnostics/mod.rs
new file mode 100644
index 0000000..ad90843
--- /dev/null
+++ b/libkabel/src/diagnostics/mod.rs
@@ -0,0 +1,24 @@
+use crate::diagnostics::span::Span;
+
+pub mod span;
+pub mod emitters;
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct Diagnostic {
+    pub diag_type: DiagnosticType,
+    pub spans: Vec<SpanWithLabel>
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum DiagnosticType {
+    Error,
+    Warning,
+    Help
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct SpanWithLabel {
+    pub span: Span,
+    pub span_type: DiagnosticType,
+    pub label: Option<String>,
+}
\ No newline at end of file
diff --git a/libkabel/src/diagnostics/span.rs b/libkabel/src/diagnostics/span.rs
new file mode 100644
index 0000000..4f36953
--- /dev/null
+++ b/libkabel/src/diagnostics/span.rs
@@ -0,0 +1,11 @@
+#[derive(Debug, Clone, PartialEq, Eq, Copy)]
+pub struct Span {
+    pub start: u64,
+    pub end: u64
+}
+
+impl Span {
+    pub fn new(start: u64, end: u64) -> Self {
+        Self { start, end }
+    }
+}
\ No newline at end of file
diff --git a/libkabel/src/error.rs b/libkabel/src/error.rs
new file mode 100644
index 0000000..0bab296
--- /dev/null
+++ b/libkabel/src/error.rs
@@ -0,0 +1,10 @@
+use crate::diagnostics::Diagnostic;
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum KError {
+    InternalError(InternalError),
+    UserError(Vec<Diagnostic>)
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum InternalError {}
\ No newline at end of file
diff --git a/libkabel/src/errors.rs b/libkabel/src/errors.rs
deleted file mode 100644
index 6f3c8d1..0000000
--- a/libkabel/src/errors.rs
+++ /dev/null
@@ -1,3 +0,0 @@
-pub enum Error {
-
-}
\ No newline at end of file
diff --git a/libkabel/src/lexer.rs b/libkabel/src/lexer/mod.rs
similarity index 54%
rename from libkabel/src/lexer.rs
rename to libkabel/src/lexer/mod.rs
index 07b8ffd..9a46516 100644
--- a/libkabel/src/lexer.rs
+++ b/libkabel/src/lexer/mod.rs
@@ -1,7 +1,10 @@
-use crate::lexutil;
-use lexutil::{ArithOperator, Bracket, Literal, Statement, Token};
-use std::error::Error;
+use token::{ArithOperator, Bracket, Literal, Statement, Token};
 use tracing::debug;
+use crate::diagnostics::{Diagnostic, DiagnosticType, SpanWithLabel};
+use crate::diagnostics::span::Span;
+use crate::error::KError;
+
+pub mod token;
 
 #[derive(Debug)]
 enum State {
@@ -11,7 +14,7 @@ enum State {
     BuildingToken,
 }
 
-pub fn lexer(text_source: &str) -> Result<Vec<Token>, Box<dyn Error>> {
+pub fn lexer(text_source: &str) -> Result<Vec<Token>, KError> {
     debug!("lexing!");
 
     let mut current_token = String::new();
@@ -20,7 +23,12 @@ pub fn lexer(text_source: &str) -> Result<Vec<Token>, Box<dyn Error>> {
 
     let mut chars = text_source.chars().peekable();
 
+    let mut pos: u64 = 0;
+    let mut span_start: u64 = 0;
+
     while let Some(c) = chars.next() {
+        pos += 1;
+
         match state {
             State::Commenting => {
                 // Stop commenting at end of line
@@ -33,9 +41,12 @@ pub fn lexer(text_source: &str) -> Result<Vec<Token>, Box<dyn Error>> {
                 if let Some(c_peek) = chars.peek() {
                     if c != '\\' && *c_peek == '\"' {
                         chars.next();
+                        pos += 1;
+
                         current_token.push(c);
                         let tok_cpy = current_token.clone();
-                        lexed.push(Token::Literal(Literal::Str(tok_cpy)));
+                        lexed.push(Token::Literal(Span::new(span_start, pos), Literal::Str(tok_cpy)));
+
                         state = State::BuildingToken;
                         current_token = String::new();
                     } else {
@@ -43,25 +54,41 @@ pub fn lexer(text_source: &str) -> Result<Vec<Token>, Box<dyn Error>> {
                     }
                 } else {
                     continue; // we're at the end. we should bring a user error
-                              // because this string was not properly delimited
+                    // because this string was not properly delimited
                 }
             }
             State::Numbering => {
                 // If next char isn't numeric, is at end of this number literal
                 if let Some(c_peek) = chars.peek() {
-                        current_token.push(c);
+                    current_token.push(c);
                     if !c_peek.is_ascii_digit() {
-                        lexed.push(Token::Literal(Literal::Num(
-                            // if this unwrap fails, we've failed
-                            // to confirm that this is a number literal
-                            current_token.parse::<f64>().unwrap(),
-                        )));
+
+                        let num = match current_token.parse::<f64>() {
+                            Ok(n) => n,
+                            Err(_) => {
+                                return Err(KError::UserError(vec![
+                                    Diagnostic {
+                                        diag_type: DiagnosticType::Error,
+                                        spans: vec![
+                                            SpanWithLabel {
+                                                span: Span::new(span_start, pos),
+                                                span_type: DiagnosticType::Error,
+                                                label: Some("this is not a valid numeric literal".to_string()),
+                                            }
+                                        ],
+                                    }
+                                ]));
+                            }
+                        };
+
+                        lexed.push(Token::Literal(
+                            Span::new(span_start, pos),
+                            Literal::Num(num)
+                        ));
                         state = State::BuildingToken;
                         current_token = String::new();
+                        span_start = pos + 1;
                     }
-                } else {
-                    continue; // we're at the end. not a problem because
-                              // numbers self-terminate
                 }
             }
             State::BuildingToken => {
@@ -70,15 +97,23 @@ pub fn lexer(text_source: &str) -> Result<Vec<Token>, Box<dyn Error>> {
                     current_token = String::new();
                     // We don't need to push c because it's the quote delimiter,
                     // which has already served its purpose as an indicator
+                    span_start = pos;
                     continue;
                 } else if c.is_ascii_digit() {
                     state = State::Numbering;
                     current_token = c.to_string();
+                    span_start = pos;
                     continue;
                 }
 
                 // Known meaningful tokens
+
+                if current_token.is_empty() {
+                    span_start = pos;
+                }
+
                 current_token.push(c);
+
                 match current_token.as_str() {
                     "\n" => {
                         continue;
@@ -88,59 +123,58 @@ pub fn lexer(text_source: &str) -> Result<Vec<Token>, Box<dyn Error>> {
                         current_token = String::new();
                     }
                     ";" => {
-                        lexed.push(Token::Statement(Statement::Terminator));
+                        lexed.push(Token::Statement(Span::new(span_start, pos), Statement::Terminator));
                         current_token = String::new();
                     }
                     "if " => {
-                        lexed.push(Token::Statement(Statement::Conditional));
+                        lexed.push(Token::Statement(Span::new(span_start, pos), Statement::Conditional));
                         current_token = String::new();
                     }
                     "to " => {
-                        lexed.push(Token::Statement(Statement::FunctionDef));
+                        lexed.push(Token::Statement(Span::new(span_start, pos), Statement::FunctionDef));
                         current_token = String::new();
                     }
                     "for " => {
-                        lexed.push(Token::Statement(Statement::ForLoop));
+                        lexed.push(Token::Statement(Span::new(span_start, pos), Statement::ForLoop));
                         current_token = String::new();
                     }
                     "while " => {
-                        lexed.push(Token::Statement(Statement::WhileLoop));
+                        lexed.push(Token::Statement(Span::new(span_start, pos), Statement::WhileLoop));
                         current_token = String::new();
                     }
                     "(" => {
-                        lexed.push(Token::Bracket(Bracket::Open));
+                        lexed.push(Token::Bracket(Span::new(span_start, pos), Bracket::Open));
                         current_token = String::new();
                     }
                     ")" => {
-                        lexed.push(Token::Bracket(Bracket::Close));
+                        lexed.push(Token::Bracket(Span::new(span_start, pos), Bracket::Close));
                         current_token = String::new();
                     }
                     "*" => {
-                        lexed.push(Token::ArithOperator(ArithOperator::Multiply));
+                        lexed.push(Token::ArithOperator(Span::new(span_start, pos), ArithOperator::Multiply));
                         current_token = String::new();
                     }
                     "/" => {
-                        lexed.push(Token::ArithOperator(ArithOperator::Divide));
+                        lexed.push(Token::ArithOperator(Span::new(span_start, pos), ArithOperator::Divide));
                         current_token = String::new();
                     }
                     "+" => {
-                        lexed.push(Token::ArithOperator(ArithOperator::Add));
+                        lexed.push(Token::ArithOperator(Span::new(span_start, pos), ArithOperator::Add));
                         current_token = String::new();
                     }
                     "-" => {
-                        lexed.push(Token::ArithOperator(ArithOperator::Subtract));
+                        lexed.push(Token::ArithOperator(Span::new(span_start, pos), ArithOperator::Subtract));
                         current_token = String::new();
                     }
                     "^" => {
-                        lexed.push(Token::ArithOperator(ArithOperator::Exponentiate));
+                        lexed.push(Token::ArithOperator(Span::new(span_start, pos), ArithOperator::Exponentiate));
                         current_token = String::new();
                     }
                     "%" => {
-                        lexed.push(Token::ArithOperator(ArithOperator::Reduce));
+                        lexed.push(Token::ArithOperator(Span::new(span_start, pos), ArithOperator::Reduce));
                         current_token = String::new();
                     }
-
-                    &_ => {}
+                    _ => {}
                 }
             }
         }
diff --git a/libkabel/src/lexutil.rs b/libkabel/src/lexer/token.rs
similarity index 71%
rename from libkabel/src/lexutil.rs
rename to libkabel/src/lexer/token.rs
index 0ad2a63..b13dc66 100644
--- a/libkabel/src/lexutil.rs
+++ b/libkabel/src/lexer/token.rs
@@ -1,3 +1,4 @@
+use crate::diagnostics::span::Span;
 use crate::variables;
 
 // parts of Token
@@ -41,9 +42,9 @@ pub enum Bracket {
 
 #[derive(Debug)]
 pub enum Token {
-    Literal(Literal),
-    ArithOperator(ArithOperator),
-    Statement(Statement),
-    Bracket(Bracket),
-    Variable(variables::Variable),
+    Literal(Span, Literal),
+    ArithOperator(Span, ArithOperator),
+    Statement(Span, Statement),
+    Bracket(Span, Bracket),
+    Variable(Span, variables::Variable),
 }
diff --git a/libkabel/src/lib.rs b/libkabel/src/lib.rs
index e2974be..0889a89 100644
--- a/libkabel/src/lib.rs
+++ b/libkabel/src/lib.rs
@@ -1,5 +1,5 @@
-pub mod errors;
-pub mod lexer;
-pub mod lexutil;
 pub mod modules;
-pub mod variables;
\ No newline at end of file
+pub mod variables;
+pub mod diagnostics;
+pub mod lexer;
+pub mod error;
\ No newline at end of file