1 files changed, 101 insertions, 0 deletions
diff --git a/dhall/src/main.rs b/dhall/src/main.rs
new file mode 100644
index 0000000..cdab3c0
--- /dev/null
+++ b/dhall/src/main.rs
@@ -0,0 +1,101 @@
+use std::io::{self, Read};
+use std::error::Error;
+use term_painter::ToStyle;
+
+use dhall::*;
+
+const ERROR_STYLE: term_painter::Color = term_painter::Color::Red;
+const BOLD: term_painter::Attr = term_painter::Attr::Bold;
+
+fn print_error(message: &str, source: &str, start: usize, end: usize) {
+    let line_number = bytecount::count(source[..start].as_bytes(), b'\n');
+    let line_start = source[..start].rfind('\n').map(|i| i + 1).unwrap_or(0);
+    let line_end = source[end..].find('\n').unwrap_or(0) + end;
+    let context_prefix = &source[line_start..start];
+    let context_highlighted = &source[start..end];
+    let context_suffix = &source[end..line_end];
+
+    let line_number_str = line_number.to_string();
+    let line_number_width = line_number_str.len();
+
+    BOLD.with(|| {
+        ERROR_STYLE.with(|| {
+            print!("error: ");
+        });
+        println!("{}", message);
+    });
+    BOLD.with(|| {
+        print!("  -->");
+    });
+    println!(" {}:{}:0", "(stdin)", line_number);
+    BOLD.with(|| {
+        println!("{:w$} |", "", w = line_number_width);
+        print!("{} |", line_number_str);
+    });
+    print!(" {}", context_prefix);
+    BOLD.with(|| {
+        ERROR_STYLE.with(|| {
+            print!("{}", context_highlighted);
+        });
+    });
+    println!("{}", context_suffix);
+    BOLD.with(|| {
+        print!("{:w$} |", "", w = line_number_width);
+        ERROR_STYLE.with(|| {
+            println!(" {:so$}{:^>ew$}", "", "",
+                     so = source[line_start..start].chars().count(),
+                     ew = ::std::cmp::max(1, source[start..end].chars().count()));
+        });
+    });
+}
+
+fn main() {
+    let mut buffer = String::new();
+    io::stdin().read_to_string(&mut buffer).unwrap();
+    let expr = match parser::parse_expr(&buffer) {
+        Ok(e) => e,
+        Err(lalrpop_util::ParseError::User { error: lexer::LexicalError::Error(pos, e) }) => {
+            print_error(&format!("Unexpected token {:?}", e), &buffer, pos, pos);
+            return;
+        }
+        Err(lalrpop_util::ParseError::UnrecognizedToken { token: Some((start, t, end)), expected: e }) => {
+            print_error(&format!("Unrecognized token {:?}", t), &buffer, start, end);
+            if !e.is_empty() {
+                println!("Expected {:?}", e);
+            }
+            return;
+        }
+        Err(e) => {
+            print_error(&format!("Parser error {:?}", e), &buffer, 0, 0);
+            return;
+        }
+    };
+
+    /*
+    expr' <- load expr
+    */
+
+    let type_expr = match typecheck::type_of(&expr) {
+        Err(e) => {
+            let explain = ::std::env::args().any(|s| s == "--explain");
+            if !explain {
+                term_painter::Color::BrightBlack.with(|| {
+                    println!("Use \"dhall --explain\" for detailed errors");
+                });
+            }
+            ERROR_STYLE.with(|| print!("Error: "));
+            println!("{}", e.type_message.description());
+            if explain {
+                println!("{}", e.type_message);
+            }
+            println!("{}", e.current);
+            // FIXME Print source position
+            return;
+        }
+        Ok(type_expr) => type_expr,
+    };
+
+    println!("{}", type_expr);
+    println!("");
+    println!("{}", normalize::<_, X, _>(&expr));
+}