refactor(location): deduplicated usage of Location::new with same value into default

notes.org

@@ -266,7 +266,7 @@ Error: unexpected token
   - Ensure examples are contextually appropriate
 
 This will make errors like "expected semicolon" more helpful by showing "expected semicolon (example: ;)".
-TODO * TODO correct all instances of <unknown> in locations
+* DONE correct all instances of <unknown> in locations
 * TODO meta-commands must be followed by end-of-file
 * TODO project code documentation
 * TODO project usage documentation

src/command.rs

@@ -1,6 +1,6 @@
 use crate::meta_commands::{MetaCommand, MetaCommandExecuteResult};
 use crate::statements::{Statement, StatementExecuteResult};
-use crate::tokens::{ScanError, Token};
+use crate::tokens::{Location, ScanError, Token};
 
 #[derive(Debug)]
 pub enum Command {
@@ -88,6 +88,7 @@ impl std::fmt::Display for ExpectedToken {
 pub enum CommandParseError {
     Scan(ScanError),
     UnexpectedToken(Token, &'static [ExpectedToken]),
+    UnexpectedEndOfFile(Location, &'static [ExpectedToken]),
 }
 
 impl From<MetaCommand> for Command {

src/error_display.rs

@@ -1,4 +1,7 @@
-use crate::{command::CommandParseError, tokens::ScanError};
+use crate::{
+    command::{CommandParseError, ExpectedToken},
+    tokens::ScanError,
+};
 use ariadne::{Color, Label, Report, ReportKind, Source};
 
 pub trait OSDBError {
@@ -22,33 +25,66 @@ impl OSDBError for CommandParseError {
                             .with_message(format!("found {token}")),
                     );
 
-                // If we have expected tokens, show an example for the first one
+                report = add_expected_tokens_to_report(report, expected_tokens);
-                if let Some(first_expected) = expected_tokens.get(0) {
-                    let example = first_expected.example();
-
-                    // Add a note with all expected types
-                    let expected_types: Vec<_> = expected_tokens
-                        .iter()
-                        .map(|t| format!("{}", t))
-                        .collect();
-                    
-                    // Use singular form when there's only one expected token type
-                    match expected_types.as_slice() {
-                        [single_type] => {
-                            report = report.with_note(format!("expected: {}", single_type));
-                        },
-                        _ => {
-                            report = report.with_note(format!("expected one of: {}", expected_types.join(", ")));
-                        }
-                    }
-                    report =
-                        report.with_help(format!("try a token of the expected type: {example}"))
-                }
 
                 report.finish().eprint((file, Source::from(input))).unwrap()
             }
+            CommandParseError::UnexpectedEndOfFile(location, expected_tokens) => {
+                let location = (file, Into::<std::ops::Range<usize>>::into(location));
+                let report = Report::build(ReportKind::Error, location)
+                    .with_message("unexpected end of file");
+                let report = add_expected_tokens_to_report(report, expected_tokens);
+                report.finish().eprint((file, Source::from(input))).unwrap()
             }
         }
+    }
+}
+
+type OSDBReport<'a> = ariadne::ReportBuilder<'a, (&'a str, std::ops::Range<usize>)>;
+
+fn add_expected_tokens_to_report<'a>(
+    mut report: OSDBReport<'a>,
+    expected_tokens: &'static [ExpectedToken],
+) -> OSDBReport<'a> {
+    // If we have expected tokens, show an example for the first one
+    if let Some(help) = expected_token_example_msg(expected_tokens) {
+        report = report.with_help(help)
+    }
+
+    // If we have at least one expected token, show a message showing what type was expected
+    if let Some(note) = expected_token_msg(expected_tokens) {
+        report = report.with_note(note);
+    }
+    report
+}
+
+fn expected_token_msg(expected_tokens: &'static [ExpectedToken]) -> Option<String> {
+    if !expected_tokens.is_empty() {
+        // Add a note with all expected types
+        let expected_types: Vec<_> = expected_tokens.iter().map(|t| format!("{}", t)).collect();
+
+        // Use singular form when there's only one expected token type
+        Some(match expected_types.as_slice() {
+            [single_type] => {
+                format!("expected: {}", single_type)
+            }
+            _ => {
+                format!("expected one of: {}", expected_types.join(", "))
+            }
+        })
+    } else {
+        // there are no expected tokens
+        None
+    }
+}
+
+fn expected_token_example_msg(expected_tokens: &'static [ExpectedToken]) -> Option<String> {
+    if let Some(first_expected) = expected_tokens.first() {
+        let example = first_expected.example();
+        Some(format!("try a token of the expected type: {example}"))
+    } else {
+        None
+    }
 }
 
 impl OSDBError for ScanError {

src/parser.rs

@@ -44,10 +44,9 @@ fn expect_semicolon(tokens: &mut VecDeque<crate::tokens::Token>) -> Result<(), C
         // Even at the end of input, we need a semicolon
         Err(CommandParseError::UnexpectedToken(
             Token {
-                location: tokens.back().map_or_else(
+                location: tokens
-                    || Location::new(String::from("<unknown>"), 0, 0),
+                    .back()
-                    |t| t.location.clone(),
+                    .map_or_else(Location::default, |t| t.location.clone()),
-                ),
                 data: TokenData::EndOfFile,
                 lexeme: String::new(),
             },
@@ -101,14 +100,22 @@ pub fn parse(file: String, input: String) -> Result<Vec<Command>, Vec<CommandPar
             TokenData::Int(_) => {
                 errs.push(CommandParseError::UnexpectedToken(
                     token,
-                    &[ExpectedToken::Statement, ExpectedToken::MetaCommand, ExpectedToken::EndOfFile],
+                    &[
+                        ExpectedToken::Statement,
+                        ExpectedToken::MetaCommand,
+                        ExpectedToken::EndOfFile,
+                    ],
                 ));
                 skip_to_next_statement(&mut tokens);
             }
             TokenData::String(_) => {
                 errs.push(CommandParseError::UnexpectedToken(
                     token,
-                    &[ExpectedToken::Statement, ExpectedToken::MetaCommand, ExpectedToken::EndOfFile],
+                    &[
+                        ExpectedToken::Statement,
+                        ExpectedToken::MetaCommand,
+                        ExpectedToken::EndOfFile,
+                    ],
                 ));
                 skip_to_next_statement(&mut tokens);
             }
@@ -128,10 +135,9 @@ fn parse_insert_command(
     let id_token = tokens.pop_front().ok_or_else(|| {
         CommandParseError::UnexpectedToken(
             Token {
-                location: tokens.back().map_or_else(
+                location: tokens
-                    || Location::new(String::from("<unknown>"), 0, 0),
+                    .back()
-                    |t| t.location.clone(),
+                    .map_or_else(Location::default, |t| t.location.clone()),
-                ),
                 data: TokenData::EndOfFile,
                 lexeme: String::new(),
             },
@@ -141,17 +147,21 @@ fn parse_insert_command(
 
     let id = match id_token.data {
         TokenData::Int(id) => id,
-        _ => return Err(CommandParseError::UnexpectedToken(id_token, &[ExpectedToken::Integer])),
+        _ => {
+            return Err(CommandParseError::UnexpectedToken(
+                id_token,
+                &[ExpectedToken::Integer],
+            ));
+        }
     };
 
     // Parse the username (string)
     let username_token = tokens.pop_front().ok_or_else(|| {
         CommandParseError::UnexpectedToken(
             Token {
-                location: tokens.back().map_or_else(
+                location: tokens
-                    || Location::new(String::from("<unknown>"), 0, 0),
+                    .back()
-                    |t| t.location.clone(),
+                    .map_or_else(Location::default, |t| t.location.clone()),
-                ),
                 data: TokenData::EndOfFile,
                 lexeme: String::new(),
             },
@@ -173,10 +183,9 @@ fn parse_insert_command(
     let email_token = tokens.pop_front().ok_or_else(|| {
         CommandParseError::UnexpectedToken(
             Token {
-                location: tokens.back().map_or_else(
+                location: tokens
-                    || Location::new(String::from("<unknown>"), 0, 0),
+                    .back()
-                    |t| t.location.clone(),
+                    .map_or_else(Location::default, |t| t.location.clone()),
-                ),
                 data: TokenData::EndOfFile,
                 lexeme: String::new(),
             },
@@ -186,7 +195,12 @@ fn parse_insert_command(
 
     let email = match email_token.data {
         TokenData::String(email) => email,
-        _ => return Err(CommandParseError::UnexpectedToken(email_token, &[ExpectedToken::String])),
+        _ => {
+            return Err(CommandParseError::UnexpectedToken(
+                email_token,
+                &[ExpectedToken::String],
+            ));
+        }
     };
 
     // Check for semicolon after the insert command

src/tokens.rs

@@ -30,6 +30,12 @@ impl From<&Location> for std::ops::Range<usize> {
     }
 }
 
+impl Default for Location {
+    fn default() -> Self {
+        Self::new(String::from("<unknown>"), 0, 0)
+    }
+}
+
 impl Location {
     /// ```
     /// use osdb::tokens::Location;