1 files changed, 71 insertions, 0 deletions
diff --git a/src/errors/mod.rs b/src/errors/mod.rs
new file mode 100644
index 0000000..b0bf7e4
--- /dev/null
+++ b/src/errors/mod.rs
@@ -0,0 +1,71 @@
+mod file_error;
+mod merge_error;
+mod resolver_error;
+
+pub use file_error::*;
+pub use merge_error::*;
+pub use resolver_error::*;
+
+use crate::*;
+
+use ansi::*;
+use log::LogLevel;
+
+
+pub fn report_source_issue(level: LogLevel, context: &Context, message: &str) {
+    // Prepare variables.
+    let in_merged = &context.source.in_merged;
+    let line_num = in_merged.start.line + 1;
+    let digits = line_num.to_string().len();
+    let w = digits + 3;
+    let arrow = "-->";
+    let mut string = message.to_string();
+
+    macro_rules! push {
+        ($($tokens:tt)*) => { string.push_str(&format!($($tokens)*)) };
+    }
+
+    // Format message and locations.
+    push!("{NORMAL}\n");
+    push!("{BLUE}{arrow:>w$}{NORMAL} {in_merged}\n", w=w);
+    if let Some(in_source) = &context.source.in_source {
+        push!("{BLUE}{arrow:>w$}{NORMAL} {in_source}\n", w=w);
+    }
+
+    // Format source context.
+    let left = in_merged.start.column;
+    let right = in_merged.end.column + 1;
+    let source_line = context.source_code.split('\n').nth(in_merged.start.line)
+        .unwrap_or("<error reading line from source>");
+    let space = " ";
+    let colour = match level {
+        LogLevel::Info => BLUE,
+        LogLevel::Warn => YELLOW,
+        LogLevel::Error => RED,
+        LogLevel::Fatal => RED,
+    };
+
+    // Print source code line.
+    push!("{BLUE} {line_num} | {NORMAL}");
+    for (i, c) in source_line.chars().enumerate() {
+        if i == left { push!("{colour}") }
+        if i == right { push!("{NORMAL}") }
+        push!("{c}");
+    }
+    push!("{NORMAL}\n");
+
+    // Print source code underline.
+    push!("{BLUE} {space:>w$} | {NORMAL}", w=digits);
+    for _ in 0..left { push!(" "); }
+    push!("{colour}");
+    for _ in left..right { push!("^"); }
+    push!("{NORMAL}");
+
+    // Print the completed message.
+    match level {
+        LogLevel::Info  => log::info!( "{}", string),
+        LogLevel::Warn  => log::warn!( "{}", string),
+        LogLevel::Error => log::error!("{}", string),
+        LogLevel::Fatal => log::fatal!("{}", string),
+    }
+}