diff --git a/Cargo.lock b/Cargo.lock
index 3e90b27..13420f4 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -101,6 +101,16 @@ dependencies = [
  "vec_map",
 ]
 
+[[package]]
+name = "codespan-reporting"
+version = "0.11.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3538270d33cc669650c4b093848450d380def10c331d38c768e34cac80576e6e"
+dependencies = [
+ "termcolor",
+ "unicode-width",
+]
+
 [[package]]
 name = "colored"
 version = "2.0.0"
@@ -391,6 +401,15 @@ dependencies = [
  "unicode-xid",
 ]
 
+[[package]]
+name = "termcolor"
+version = "1.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2dfed899f0eb03f32ee8c6a0aabdb8a7949659e3466561fc0adf54e26d88c5f4"
+dependencies = [
+ "winapi-util",
+]
+
 [[package]]
 name = "textwrap"
 version = "0.11.0"
@@ -436,12 +455,14 @@ name = "today"
 version = "0.1.0"
 dependencies = [
  "chrono",
+ "codespan-reporting",
  "colored",
  "computus",
  "directories",
  "pest",
  "pest_derive",
  "structopt",
+ "termcolor",
  "thiserror",
  "tzfile",
 ]
@@ -519,6 +540,15 @@ version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
 
+[[package]]
+name = "winapi-util"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "70ec6ce85bb158151cae5e5c87f95a8e97d2c0c4b001223f33a334e3ce5de178"
+dependencies = [
+ "winapi",
+]
+
 [[package]]
 name = "winapi-x86_64-pc-windows-gnu"
 version = "0.4.0"
diff --git a/Cargo.toml b/Cargo.toml
index d0b6eb2..458483b 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -5,11 +5,13 @@ edition = "2021"
 
 [dependencies]
 chrono = "0.4.19"
+codespan-reporting = "0.11.1"
 colored = "2.0.0"
 computus = "1.0.0"
 directories = "4.0.1"
 pest = "2.1.3"
 pest_derive = "2.1.0"
 structopt = "0.3.25"
+termcolor = "1.1.2"
 thiserror = "1.0.30"
 tzfile = { git = "https://github.com/Garmelon/tzfile.git", branch = "tzdir" }
diff --git a/src/files.rs b/src/files.rs
index 3022ef1..1e1f8bd 100644
--- a/src/files.rs
+++ b/src/files.rs
@@ -4,6 +4,10 @@ use std::fs;
 use std::path::{Path, PathBuf};
 
 use chrono::{DateTime, NaiveDate, Utc};
+use codespan_reporting::diagnostic::Diagnostic;
+use codespan_reporting::files::SimpleFiles;
+use codespan_reporting::term::{self, Config};
+use termcolor::StandardStream;
 use tzfile::Tz;
 
 use self::commands::{Command, Done, File};
@@ -16,22 +20,26 @@ mod format;
 mod parse;
 pub mod primitives;
 
+// TODO Move file content from `File` to `LoadedFile`
 #[derive(Debug)]
 struct LoadedFile {
-    /// Canonical path for this file
+    /// Canonical path for this file.
     path: PathBuf,
-    // User-readable path for this file
+    /// User-readable path for this file.
     name: PathBuf,
+    /// Identifier for codespan-reporting.
+    cs_id: usize,
     file: File,
-    /// Whether this file has been changed
+    /// Whether this file has been changed.
     dirty: bool,
 }
 
 impl LoadedFile {
-    pub fn new(path: PathBuf, name: PathBuf, file: File) -> Self {
+    pub fn new(path: PathBuf, name: PathBuf, cs_id: usize, file: File) -> Self {
         Self {
             path,
             name,
+            cs_id,
             file,
             dirty: false,
         }
@@ -48,10 +56,6 @@ impl Source {
     pub fn new(file: usize, command: usize) -> Self {
         Self { file, command }
     }
-
-    pub fn file(&self) -> usize {
-        self.file
-    }
 }
 
 #[derive(Debug)]
@@ -63,6 +67,8 @@ pub struct SourcedCommand<'a> {
 #[derive(Debug)]
 pub struct Files {
     files: Vec<LoadedFile>,
+    /// Codespan-reporting file database.
+    cs_files: SimpleFiles<String, String>,
     timezone: Tz,
     logs: HashMap<NaiveDate, Source>,
 }
@@ -75,12 +81,14 @@ impl Files {
         let mut loaded = HashSet::new();
 
         let mut files = vec![];
-        Self::load_file(&mut loaded, &mut files, path)?;
+        let mut cs_files = SimpleFiles::new();
+        Self::load_file(&mut loaded, &mut files, &mut cs_files, path)?;
 
         let timezone = Self::determine_timezone(&files)?;
         let logs = Self::collect_logs(&files)?;
         Ok(Self {
             files,
+            cs_files,
             timezone,
             logs,
         })
@@ -89,6 +97,7 @@ impl Files {
     fn load_file(
         loaded: &mut HashSet<PathBuf>,
         files: &mut Vec<LoadedFile>,
+        cs_files: &mut SimpleFiles<String, String>,
         name: &Path,
     ) -> Result<()> {
         let path = name.canonicalize().map_err(|e| Error::ResolvePath {
@@ -118,13 +127,14 @@ impl Files {
             .collect::<Vec<_>>();
 
         loaded.insert(path.clone());
-        files.push(LoadedFile::new(path, name.to_owned(), file));
+        let cs_id = cs_files.add(path.to_string_lossy().to_string(), content);
+        files.push(LoadedFile::new(path, name.to_owned(), cs_id, file));
 
         for include in includes {
             // Since we've successfully opened the file, its name can't be the
             // root directory or empty string and it must thus have a parent.
             let include_path = name.parent().unwrap().join(include);
-            Self::load_file(loaded, files, &include_path)?;
+            Self::load_file(loaded, files, cs_files, &include_path)?;
         }
 
         Ok(())
@@ -253,4 +263,14 @@ impl Files {
         true
     }
     */
+
+    /* Errors */
+
+    pub fn eprint_diagnostic(&self, diagnostic: &Diagnostic<usize>) {
+        let mut out = StandardStream::stderr(termcolor::ColorChoice::Auto);
+        let config = Config::default();
+        if let Err(e) = term::emit(&mut out, &config, &self.cs_files, diagnostic) {
+            panic!("Error while reporting error: {}", e);
+        }
+    }
 }