Introduced primitive error logger.

src/main.rs

@@ -1,5 +1,18 @@
-use std::{env, fs, io, process};
 use std::io::Write;
+use std::{env, fs, io, process};
+
+mod error_codes {
+ pub const ERROR_INVALID_SCHEMA_FILE: i32 = 1;
+ pub const ERROR_INVALID_SCHEMA: i32 = 2;
+ pub const ERROR_BAD_QUERY: i32 = 3;
+}
+
+fn error_log<E>(error_code: i32, message: &str, err: E)
+where
+ E: std::fmt::Display,
+{
+ eprintln!("ERROR {}: {}: {}", error_code, message, err);
+}
 
 fn main() {
  // Get the schema file from the command line arguments or use the default.
@@ -9,12 +22,20 @@ fn main() {
 
  // Read the schema file and parse it into a schema object.
  let schema_file = fs::read_to_string(schema_file).unwrap_or_else(|err| {
- eprintln!("Error reading schema file: {}", err);
+ error_log(
+ error_codes::ERROR_INVALID_SCHEMA_FILE,
+ "Couldn't read schema file",
+ err,
+ );
  process::exit(error_codes::ERROR_INVALID_SCHEMA_FILE);
  });
 
  let schema = minigraf::parse_schema(&schema_file).unwrap_or_else(|err| {
- eprintln!("Error parsing schema: {}", err);
+ error_log(
+ error_codes::ERROR_INVALID_SCHEMA,
+ "Couldn't parse schema",
+ err,
+ );
  process::exit(error_codes::ERROR_INVALID_SCHEMA);
  });
  dbg!("schema: {:#?}", &schema);
@@ -33,14 +54,13 @@ fn main() {
  // Parse the query into a query object.
  let query = minigraf::parse_query(query);
  if query.is_err() {
- eprintln!("Error parsing query: {}", query.unwrap_err());
+ error_log(
+ error_codes::ERROR_BAD_QUERY,
+ "Couldn't parse query",
+ query.err().unwrap(),
+ );
  continue;
  }
  dbg!("query: {:#?}", &query);
  }
 }
-
-mod error_codes {
- pub const ERROR_INVALID_SCHEMA_FILE: i32 = 1;
- pub const ERROR_INVALID_SCHEMA: i32 = 2;
-}