Fixed invalid minus sign interpretation.

Bug examples:
array(5)[0] - 3 would become 2, but array(5)[0] -3 would become string '5 -3'.
2 - 3, 2-3 and 2- 3 would become -1, but 2 -3 and 2     -3 would become string '2 -3'.

This commit fixes the minus sign interpretation by the lexer, ignoring whitespaces in front of the '-' sign and with an additional case to support array_get's in format "@A[0]-value".

Author: Pieter12345

src/main/java/com/laytonsmith/core/MethodScriptCompiler.java

@@ -798,23 +798,32 @@ public static TokenStream lex(String script, File file, boolean inPureMScript, b
 
 			// Convert "-" + number to -number if allowed.
 			it.previous(); // Select 't' <--.
-			if(it.hasPrevious()) {
+			if(it.hasPrevious() && t.type == TType.UNKNOWN) {
 				Token prev1 = it.previous(); // Select 'prev1' <--.
-				if(it.hasPrevious()) {
-					Token prev2 = it.previous(); // Select 'prev2' <--.
-					if(t.type == TType.UNKNOWN && prev1.type.isPlusMinus() // Convert "± UNKNOWN".
-							&& !prev2.type.isIdentifier() // Don't convert "number/string/var ± ...".
-							&& prev2.type != TType.FUNC_END // Don't convert "func() ± ...".
-							&& !IVAR_PATTERN.matcher(t.val()).matches() // Don't convert "± @var".
-							&& !VAR_PATTERN.matcher(t.val()).matches()) { // Don't convert "± $var".
-						// It is a negative/positive number: Absorb the sign.
-						t.value = prev1.value + t.value;
-						it.next(); // Select 'prev2' -->.
-						it.next(); // Select 'prev1' -->.
-						it.remove(); // Remove 'prev1'.
-					} else {
-						it.next(); // Select 'prev2' -->.
-						it.next(); // Select 'prev1' -->.
+				if(prev1.type.isPlusMinus()) {
+					
+					// Find the first non-whitespace token before the '-'.
+					Token prevNonWhitespace = null;
+					while(it.hasPrevious()) {
+						if(it.previous().type != TType.WHITESPACE) {
+							prevNonWhitespace = it.next();
+							break;
+						}
+					}
+					while(it.next() != prev1) { // Skip until selection is at 'prev1 -->'.
+					}
+					
+					if(prevNonWhitespace != null) {
+						 // Convert "±UNKNOWN" if the '±' is used as a sign (and not an add/subtract operation).
+						if(!prevNonWhitespace.type.isIdentifier() // Don't convert "number/string/var ± ...".
+								&& prevNonWhitespace.type != TType.FUNC_END // Don't convert "func() ± ...".
+								&& prevNonWhitespace.type != TType.RSQUARE_BRACKET // Don't convert "] ± ..." (arrays).
+								&& !IVAR_PATTERN.matcher(t.val()).matches() // Don't convert "± @var".
+								&& !VAR_PATTERN.matcher(t.val()).matches()) { // Don't convert "± $var".
+							// It is a negative/positive number: Absorb the sign.
+							t.value = prev1.value + t.value;
+							it.remove(); // Remove 'prev1'.
+						}
 					}
 				} else {
 					it.next(); // Select 'prev1' -->.

src/test/java/com/laytonsmith/core/MethodScriptCompilerTest.java

@@ -1118,4 +1118,51 @@ private void ambigousCommandRegistrationHelper(String cmd1, String cmd2, boolean
 		}
 	}
 
+	@Test
+	public void testMinusSignHandling() throws Exception {
+		// This tests a specific lexer part where token TType.MINUS ('-' sign) is merged with the next token
+		// based on whether the MINUS is used as a negation sign or a mathematical operator.
+		
+		// "... - 2".
+		this.verifyExecute("msg(5 - 2)", "3");
+		this.verifyExecute("msg(5- 2)", "3");
+		this.verifyExecute("msg(5 -2)", "3");
+		this.verifyExecute("msg(5-2)", "3");
+		this.verifyExecute("@arr = array(5); msg(@arr[0] - 2)", "3");
+		this.verifyExecute("@arr = array(5); msg(@arr[0]- 2)", "3");
+		this.verifyExecute("@arr = array(5); msg(@arr[0] -2)", "3");
+		this.verifyExecute("@arr = array(5); msg(@arr[0]-2)", "3");
+		this.verifyExecute("@a = 5; msg(@a - 2)", "3");
+		this.verifyExecute("@a = 5; msg(@a- 2)", "3");
+		this.verifyExecute("@a = 5; msg(@a -2)", "3");
+		this.verifyExecute("@a = 5; msg(@a-2)", "3");
+		this.verifyExecute("msg(abs(5) - 2)", "3");
+		this.verifyExecute("msg(abs(5)- 2)", "3");
+		this.verifyExecute("msg(abs(5) -2)", "3");
+		this.verifyExecute("msg(abs(5)-2)", "3");
+		
+		// "2 - ...".
+		this.verifyExecute("@arr = array(5); msg(2 - @arr[0])", "-3");
+		this.verifyExecute("@arr = array(5); msg(2- @arr[0])", "-3");
+		this.verifyExecute("@arr = array(5); msg(2 -@arr[0])", "-3");
+		this.verifyExecute("@arr = array(5); msg(2-@arr[0])", "-3");
+		this.verifyExecute("@a = 5; msg(2 - @a)", "-3");
+		this.verifyExecute("@a = 5; msg(2- @a)", "-3");
+		this.verifyExecute("@a = 5; msg(2 -@a)", "-3");
+		this.verifyExecute("@a = 5; msg(2-@a)", "-3");
+		this.verifyExecute("msg(2 - abs(5))", "-3");
+		this.verifyExecute("msg(2- abs(5))", "-3");
+		this.verifyExecute("msg(2 -abs(5))", "-3");
+		this.verifyExecute("msg(2-abs(5))", "-3");
+	}
+	
+	private void verifyExecute(String script, String expectedResponse) throws ConfigCompileException, ConfigCompileGroupException {
+		MCPlayer temp = this.env.getEnv(CommandHelperEnvironment.class).GetPlayer();
+		MCPlayer player = StaticTest.GetOnlinePlayer();
+		this.env.getEnv(CommandHelperEnvironment.class).SetPlayer(player);
+		MethodScriptCompiler.execute(MethodScriptCompiler.compile(
+				MethodScriptCompiler.lex(script, null, true)), this.env, null, null);
+		verify(player).sendMessage(expectedResponse);
+		this.env.getEnv(CommandHelperEnvironment.class).SetPlayer(temp);
+	}
 }