[muscript] Generate error data in create method, not in toString

muscript/src/main/java/io/gitlab/jfronny/muscript/compiler/Error.java

@@ -3,29 +3,44 @@ package io.gitlab.jfronny.muscript.compiler;
 /**
  * Class for storing errors produced while parsing.
  */
-public record Error(String source, int character, String message) {
-    @Override
-    public String toString() {
-        StringBuilder builder = new StringBuilder();
-        if (character >= source.length()) {
-            builder.append("Error at character ").append(character);
-        }
-        else {
-            builder.append("Error at '").append(source.charAt(character)).append("' (character ").append(character).append(")");
-        }
-        builder.append(": ").append(message);
-
+public record Error(String message, String line, int lineNumber, int column) {
+    /**
+     * Generates an error by getting the relevant data from what is available while lexing/parsing
+     * @param source The complete source for the code that generated this error
+     * @param character The index of the current character
+     * @param message The error message
+     * @return An error using the provided information
+     */
+    public static Error create(String source, int character, String message) {
         int lineStart = source.lastIndexOf('\n', character);
         int lineEnd = source.indexOf('\n', character);
         if (lineEnd == -1) lineEnd = source.length();
 
-        String line = source.substring(lineStart + 1, lineEnd);
-        int lineNumber = lineStart > 0 ? (int) source.substring(0, lineStart).chars().filter(c -> c == '\n').count() : 1;
+        int lineIndex = lineStart > 0 ? (int) source.substring(0, lineStart).chars().filter(c -> c == '\n').count() : 0;
+        int column = character - lineStart;
+
+        return new Error(message, source.substring(lineStart + 1, lineEnd), lineIndex + 1, column);
+    }
+
+    /**
+     * Converts this error to a human-readable error message
+     * @return A string representation
+     */
+    @Override
+    public String toString() {
+        StringBuilder builder = new StringBuilder();
+
+        if (column > line.length())
+            builder.append("Error at character ").append(column);
+        else
+            builder.append("Error at '").append(line.charAt(column - 1)).append("' (character ").append(column).append(")");
+        builder.append(": ").append(message);
 
         String linePrefix = String.format("%1$6d", lineNumber) + " | ";
 
         builder.append('\n').append(linePrefix).append(line);
-        builder.append('\n').append(" ".repeat(linePrefix.length() + (character - lineStart - 1))).append("^-- Here");
+        builder.append('\n').append(" ".repeat(linePrefix.length() + (column - 1))).append("^-- Here");
+
         return builder.toString();
     }
 }

muscript/src/main/java/io/gitlab/jfronny/muscript/compiler/Parser.java

@@ -230,7 +230,7 @@ public class Parser {
 
     // Helpers
     private ParseException error(String message) {
-        return new ParseException(new Error(lexer.source, current.current - 1, message));
+        return new ParseException(Error.create(lexer.source, current.current - 1, message));
     }
 
     private TokenData consume(Token token, String message) {

muscript/src/test/java/io/gitlab/jfronny/muscript/test/ErrorTest.java

@@ -9,17 +9,17 @@ public class ErrorTest {
     @Test
     void invalidCode() {
         assertEquals("""
-                Error at 'e' (character 8): Expected number but is Boolean
+                Error at 'e' (character 9): Expected number but is Boolean
                      1 | 15 + true
                                  ^-- Here""",
                 assertThrows(Parser.ParseException.class, () -> Parser.parse("15 + true")).error.toString());
         assertEquals("""
-                Error at ''' (character 9): Expected number but is String
+                Error at ''' (character 10): Expected number but is String
                      1 | 15 + 'yes'
                                   ^-- Here""",
                 assertThrows(Parser.ParseException.class, () -> Parser.parse("15 + 'yes'")).error.toString());
         assertEquals("""
-                Error at '=' (character 7): Unexpected character
+                Error at '=' (character 8): Unexpected character
                      1 | string = 'Value'
                                 ^-- Here""",
                 assertThrows(Parser.ParseException.class, () -> Parser.parse("string = 'Value'")).error.toString());