From 73bcf82d1e1364fe2df32a746a2482f1f6a4e679 Mon Sep 17 00:00:00 2001
From: Mark <mverleg.noreply@gmail.com>
Date: Mon, 4 Jun 2018 21:49:44 +0200
Subject: [PATCH] More lexing possibilities #52

---
 src/mango/lexing/code_lexer.rs        | 16 ++++++++++++++--
 src/mango/token/tests.rs              |  2 +-
 src/mango/token/tokens/association.rs |  6 +++++-
 src/mango/util/strslice/slice.rs      |  2 +-
 4 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/src/mango/lexing/code_lexer.rs b/src/mango/lexing/code_lexer.rs
index 5574f253..a371a7dc 100644
--- a/src/mango/lexing/code_lexer.rs
+++ b/src/mango/lexing/code_lexer.rs
@@ -4,6 +4,7 @@ use mango::lexing::string_lexer::StringLexer;
 use mango::lexing::typ::Lexer;
 use mango::lexing::typ::MaybeToken;
 use mango::token::special::UnlexableToken;
+use mango::token::tokens::AssociationToken;
 use mango::token::tokens::EndBlockToken;
 use mango::token::tokens::EndStatementToken;
 use mango::token::tokens::IdentifierToken;
@@ -155,6 +156,19 @@ impl Lexer for CodeLexer {
                     self.reader_or_delegate = ReaderOrDelegate::Delegate(sublexer);
                     return self.lex();
                 }
+                // Association (before operator)
+                let association_match_res = self
+                    .reader
+                    .borrow_mut()
+                    .matches(&AssociationToken::subpattern());
+                if let Match(token) = association_match_res {
+                    if token.chars().last().unwrap() == '=' {
+                        //                        return Token(Tokens::Association(AssociationToken::from_str(token[..1]).unwrap()));
+                        return Token(Tokens::Association(AssociationToken::from_unprefixed())); // TODO
+                    } else {
+                        return Token(Tokens::Association(AssociationToken::from_unprefixed()));
+                    }
+                }
                 // Operator
                 let operator_match_res = self
                     .reader
@@ -163,8 +177,6 @@ impl Lexer for CodeLexer {
                 if let Match(token) = operator_match_res {
                     return Token(Tokens::Operator(OperatorToken::from_str(&token).unwrap()));
                 }
-                // Association
-                // todo
                 // Grouping symbols
                 if let Match(_) = self.reader.borrow_mut().matches("(") {
                     return Token(Tokens::ParenthesisOpen(ParenthesisOpenToken::new()));
diff --git a/src/mango/token/tests.rs b/src/mango/token/tests.rs
index 732d01a3..6b4ce6b8 100644
--- a/src/mango/token/tests.rs
+++ b/src/mango/token/tests.rs
@@ -15,7 +15,7 @@ fn test_tokens_eq() {
         Keyword(KeywordToken::from_str("let").unwrap()),
         Keyword(KeywordToken::from_str("mut").unwrap()),
         Identifier(IdentifierToken::from_name(my_var)),
-        Association(AssociationToken::from_unmutated()),
+        Association(AssociationToken::from_unprefixed()),
         Literal(LiteralToken::int(21)),
         EndStatement(EndStatementToken::new_semicolon()),
         Identifier(IdentifierToken::from_name(my_var)),
diff --git a/src/mango/token/tokens/association.rs b/src/mango/token/tokens/association.rs
index a8c44da2..1c857ee2 100644
--- a/src/mango/token/tokens/association.rs
+++ b/src/mango/token/tokens/association.rs
@@ -11,7 +11,7 @@ pub struct AssociationToken {
 }
 
 impl AssociationToken {
-    pub fn from_unmutated() -> Self {
+    pub fn from_unprefixed() -> Self {
         AssociationToken {
             symbol: Option::None,
         }
@@ -26,6 +26,10 @@ impl AssociationToken {
             symbol: Option::Some(symbol),
         }
     }
+
+    pub fn subpattern() -> String {
+        format!("{}=", Symbol::subpattern())
+    }
 }
 
 impl ToText for AssociationToken {
diff --git a/src/mango/util/strslice/slice.rs b/src/mango/util/strslice/slice.rs
index 88eea284..3260c401 100644
--- a/src/mango/util/strslice/slice.rs
+++ b/src/mango/util/strslice/slice.rs
@@ -29,7 +29,7 @@ pub fn charslice<S: Into<String>>(text: S, start: isize, end: isize) -> String {
         let new_end = (charcount as isize + end) as usize;
         assert!(
             new_end >= from,
-            "charslice: 'start' may not be before 'end' (end was positive)"
+            "charslice: 'start' may not be before 'end' (end was negative)"
         );
         length = new_end - from;
     } else {