From 8eda74c9a506649edfd882df42a482d5515ffe20 Mon Sep 17 00:00:00 2001
From: greg <greg.shuflin@protonmail.com>
Date: Sat, 5 Jan 2019 17:18:10 -0800
Subject: [PATCH] Starting to keep track of locations of errors in file

---
 schala-lang/codegen/src/lib.rs      |  4 ++--
 schala-lang/language/src/lib.rs     |  8 ++++++-
 schala-lang/language/src/parsing.rs | 34 ++++++++++++++++++++---------
 3 files changed, 33 insertions(+), 13 deletions(-)

diff --git a/schala-lang/codegen/src/lib.rs b/schala-lang/codegen/src/lib.rs
index 7ba53ec..b28ddbc 100644
--- a/schala-lang/codegen/src/lib.rs
+++ b/schala-lang/codegen/src/lib.rs
@@ -19,7 +19,7 @@ impl Fold for RecursiveDescentFn {
 
     let new_block: syn::Block = parse_quote! {
       {
-        let next_token_before_parse = self.peek_with_token_offset();
+        let next_token_before_parse = self.token_handler.peek_token();
         let record = ParseRecord {
           production_name: stringify!(#ident).to_string(),
           next_token: format!("{}", next_token_before_parse.to_string_with_metadata()),
@@ -34,7 +34,7 @@ impl Fold for RecursiveDescentFn {
         }
         match result {
           Err(ParseError { token: None, msg }) =>  {
-            let next_token_after_parse = self.peek_with_token_offset();
+            let next_token_after_parse = self.token_handler.peek_token();
             println!("HERE? {:?}", next_token_after_parse);
             Err(ParseError { token: Some(next_token_after_parse), msg })
           },
diff --git a/schala-lang/language/src/lib.rs b/schala-lang/language/src/lib.rs
index 57d060e..8585e28 100644
--- a/schala-lang/language/src/lib.rs
+++ b/schala-lang/language/src/lib.rs
@@ -124,7 +124,13 @@ fn parsing(handle: &mut Schala, input: Vec<tokenizing::Token>, comp: Option<&mut
       Some(ref x) => println!("Bad parsing debug option: {}", x),
     };
   });
-  ast.map_err(|err| err.msg)
+  ast.map_err(|error: parsing::ParseError| {
+    let location_frag = match error.token {
+      Some(tok) => format!(" at line: {} column: {}", tok.offset.0, tok.offset.1),
+      None => "".into()
+    };
+    format!("'{}'{}", error.msg, location_frag)
+  })
 }
 
 fn symbol_table(handle: &mut Schala, input: ast::AST, comp: Option<&mut UnfinishedComputation>) -> Result<ast::AST, String> {
diff --git a/schala-lang/language/src/parsing.rs b/schala-lang/language/src/parsing.rs
index d79f14d..c38640b 100644
--- a/schala-lang/language/src/parsing.rs
+++ b/schala-lang/language/src/parsing.rs
@@ -23,6 +23,13 @@ impl ParseError {
       token: None
     })
   }
+
+  fn new_with_token<T>(msg: &str, t: Token) -> ParseResult<T>{
+    Err(ParseError {
+      msg: msg.to_string(),
+      token: Some(t)
+    })
+  }
 }
 
 pub type ParseResult<T> = Result<T, ParseError>;
@@ -47,19 +54,26 @@ struct ParserRestrictions {
 
 struct TokenHandler {
   tokens: Peekable<IntoIter<Token>>,
+  end_of_file: (usize, usize),
 }
 
 impl TokenHandler {
   fn new(tokens: Vec<Token>) -> TokenHandler {
+    let end_of_file = match tokens.last() {
+      None => (0, 0),
+      Some(s) => {
+        s.offset.clone()
+      }
+    };
     let tokens = tokens.into_iter().peekable();
-    TokenHandler { tokens }
+    TokenHandler { tokens, end_of_file }
   }
 
   fn peek(&mut self) -> TokenKind {
     self.tokens.peek().map(|ref t| { t.kind.clone() }).unwrap_or(TokenKind::EOF)
   }
-  fn peek_with_token_offset(&mut self) -> Token {
-    self.tokens.peek().map(|t: &Token| { t.clone()}).unwrap_or(Token { kind: TokenKind::EOF, offset: (0,0)})
+  fn peek_token(&mut self) -> Token {
+    self.tokens.peek().map(|t: &Token| { t.clone()}).unwrap_or(Token { kind: TokenKind::EOF, offset: self.end_of_file})
   }
   fn next(&mut self) -> TokenKind {
     self.tokens.next().map(|ref t| { t.kind.clone() }).unwrap_or(TokenKind::EOF)
@@ -79,9 +93,6 @@ impl Parser {
   fn peek(&mut self) -> TokenKind {
     self.token_handler.peek()
   }
-  fn peek_with_token_offset(&mut self) -> Token {
-    self.token_handler.peek_with_token_offset()
-  }
   fn next(&mut self) -> TokenKind {
     self.token_handler.next()
   }
@@ -544,7 +555,7 @@ impl Parser {
   fn precedence_expr(&mut self, precedence: i32) -> ParseResult<Expression> {
     let record = ParseRecord {
       production_name: "precedence_expr".to_string(),
-      next_token: format!("{}", self.peek_with_token_offset().to_string_with_metadata()),
+      next_token: format!("{}", self.token_handler.peek_token().to_string_with_metadata()),
       level: self.parse_level,
     };
     self.parse_level += 1;
@@ -994,7 +1005,10 @@ impl Parser {
   #[recursive_descent_method]
   fn literal(&mut self) -> ParseResult<Expression> {
     use self::ExpressionType::*;
-    match self.peek() {
+
+    let tok = self.token_handler.peek_token();
+    let kind = tok.kind.clone();
+    match kind {
       DigitGroup(_) | HexLiteral(_) | BinNumberSigil | Period => self.number_literal(),
       Keyword(Kw::True) => {
         self.next();
@@ -1006,9 +1020,9 @@ impl Parser {
       },
       StrLiteral(s) => {
         self.next();
-        Ok(Expression(StringLiteral(s), None))
+        Ok(Expression(StringLiteral(s.clone()), None))
       }
-      e => ParseError::new(&format!("Expected a literal expression, got {:?}", e)),
+      e => ParseError::new_with_token(&format!("Expected a literal expression, got {:?}", e), tok),
     }
   }