From 5016fefc14109dc171ca2abcbd4e3fb767b428f4 Mon Sep 17 00:00:00 2001
From: Guy C <gc1523@ic.ac.uk>
Date: Tue, 4 Feb 2025 03:02:37 +0000
Subject: [PATCH] feat: lexer implements ErrorConfig for improved error
 messages

---
 src/main/wacc/lexer.scala | 34 +++++++++++++++++++++++++++++++++-
 1 file changed, 33 insertions(+), 1 deletion(-)

diff --git a/src/main/wacc/lexer.scala b/src/main/wacc/lexer.scala
index 094ac12..ceeec45 100644
--- a/src/main/wacc/lexer.scala
+++ b/src/main/wacc/lexer.scala
@@ -4,7 +4,39 @@ import parsley.Parsley
 import parsley.character
 import parsley.token.{Basic, Lexer}
 import parsley.token.descriptions.*
+import parsley.token.errors._
+import parsley.errors._
 
+val errConfig = new ErrorConfig {
+  override def labelSymbol = Map(
+    "!=" -> Label("binary operator"),
+    "%" -> Label("binary operator"),
+    "&&" -> Label("binary operator"),
+    "*" -> Label("binary operator"),
+    "+" -> Label("binary operator"),
+    "-" -> Label("binary operator"),
+    "/" -> Label("binary operator"),
+    "<" -> Label("binary operator"),
+    "<=" -> Label("binary operator"),
+    "==" -> Label("binary operator"),
+    ">" -> Label("binary operator"),
+    ">=" -> Label("binary operator"),
+    "||" -> Label("binary operator"),
+    "!" -> Label("unary operator"),
+    "len" -> Label("unary operator"),
+    "ord" -> Label("unary operator"),
+    "chr" -> Label("unary operator"),
+    "bool" -> Label("valid type"),
+    "char" -> Label("valid type"),
+    "int" -> Label("valid type"),
+    "pair" -> Label("valid type"),
+    "string" -> Label("valid type"),
+    "fst" -> Label("pair extraction"),
+    "snd" -> Label("pair extraction"),
+    "false" -> Label("boolean value"),
+    "true" -> Label("boolean value")
+  )
+}
 object lexer {
   private val desc = LexicalDesc.plain.copy(
     nameDesc = NameDesc.plain.copy(
@@ -43,7 +75,7 @@ object lexer {
     )
   )
 
-  private val lexer = Lexer(desc)
+  private val lexer = Lexer(desc, errConfig)
   val ident = lexer.lexeme.names.identifier
   val integer = lexer.lexeme.integer.decimal32[Int]
   val negateCheck = lexer.nonlexeme.symbol("-") ~> character.digit