feat(#3744): Human-Readable Message for Prohibited Comment

eo-parser/src/main/antlr4/org/eolang/parser/Eo.g4

@@ -263,16 +263,24 @@ vapplicationArgsReversed
 
 // Arguments of vertical application
 // Must either all bound or all unbound
+// Comments between vertical arguments are prohibited
 // Ends on the next line
 vapplicationArgsSpecific
     : vapplicationArgBound+
     | vapplicationArgUnbound+
     ;
 
+// Prohibited comment between vertical arguments
+// If this rule is matched, the parser will throw an error
+prohibitedComment
+    : comment
+    ;
+
 // Vertical application arguments with bindings
 vapplicationArgBound
     : vapplicationArgBoundCurrent EOL
     | vapplicationArgBoundNext
+    | prohibitedComment+
     ;
 
 // Vertical application arguments with bindings
@@ -296,6 +304,7 @@ vapplicationArgBoundNext
 vapplicationArgUnbound
     : vapplicationArgUnboundCurrent EOL
     | vapplicationArgUnboundNext
+    | prohibitedComment+
     ;
 
 // Vertical application arguments without bindings

eo-parser/src/main/java/org/eolang/parser/XeEoListener.java

@@ -580,6 +580,18 @@ public void exitVapplicationArgs(final EoParser.VapplicationArgsContext ctx) {
         // Nothing here
     }
 
+    @Override
+    public void enterProhibitedComment(final EoParser.ProhibitedCommentContext ctx) {
+        this.errors.add(
+            XeEoListener.error(ctx.comment().COMMENTARY(), "Comment here is prohibited")
+        );
+    }
+
+    @Override
+    public void exitProhibitedComment(final EoParser.ProhibitedCommentContext ctx) {
+        // Nothing here
+    }
+
     @Override
     public void enterVapplicationArgsReversed(final EoParser.VapplicationArgsReversedContext ctx) {
         // Nothing here
@@ -1256,7 +1268,7 @@ private static String trimMargin(final String text, final int indent) {
      * Create parsing exception from given context.
      * @param ctx Context
      * @param msg Error message
-     * @return Parsing exception from current context
+     * @return Parsing exception from the current context
      */
     private static ParsingException error(final ParserRuleContext ctx, final String msg) {
         return new ParsingException(
@@ -1274,13 +1286,43 @@ private static ParsingException error(final ParserRuleContext ctx, final String
         );
     }
 
+    /**
+     * Create parsing exception from given terminal node.
+     * @param terminal Terminal node
+     * @param msg Error message
+     * @return Parsing exception from the current terminal node
+     */
+    private static ParsingException error(final TerminalNode terminal, final String msg) {
+        return new ParsingException(
+            terminal.getSymbol().getLine(),
+            new MsgLocated(
+                terminal.getSymbol().getLine(),
+                terminal.getSymbol().getCharPositionInLine(),
+                msg
+            ).formatted(),
+            new MsgUnderlined(
+                XeEoListener.line(terminal.getSymbol()),
+                terminal.getSymbol().getCharPositionInLine(),
+                terminal.getText().length()
+            ).formatted()
+        );
+    }
+
     /**
      * Get line from context.
      * @param ctx Context
      * @return Line
      */
     private static String line(final ParserRuleContext ctx) {
-        final Token token = ctx.start;
+        return XeEoListener.line(ctx.start);
+    }
+
+    /**
+     * Get line from token.
+     * @param token Token
+     * @return Line
+     */
+    private static String line(final Token token) {
         final int number = token.getLine();
         final String[] lines = token.getInputStream().toString().split("\n");
         if (number > 0 && number <= lines.length) {

eo-parser/src/test/java/org/eolang/parser/EoSyntaxTest.java

@@ -279,10 +279,10 @@ void checksTypoPacks(final String yaml) {
         if (story.map().containsKey(msg)) {
             MatcherAssert.assertThat(
                 XhtmlMatchers.xhtml(story.after()).toString(),
-                story.after()
-                    .xpath("/program/errors/error[1]/text()")
-                    .get(0)
-                    .replaceAll("\r", ""),
+                String.join(
+                    "\n",
+                    story.after().xpath("/program/errors/error/text()")
+                ).replaceAll("\r", ""),
                 Matchers.equalTo(story.map().get(msg).toString())
             );
         }

eo-parser/src/test/resources/org/eolang/parser/eo-typos/comment-in-method.yaml

@@ -20,13 +20,11 @@
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 # SOFTWARE.
 ---
-line: 5
-# @todo #3706:30min The error message doesn't highlight the exact position of the
-#  comment. The error message should be updated to point to the exact position
-#  of the comment.
-message: |
-  [5:12] error: 'Invalid object declaration'
-      sprintwf
+line: 4
+message: |-
+  [4:4] error: 'Comment here is prohibited'
+      # a comment here is prohibited
+      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 input: |
   # No comments
   [args] > app

eo-parser/src/test/resources/org/eolang/parser/eo-typos/comments-in-method-several.yaml

@@ -0,0 +1,42 @@
+# The MIT License (MIT)
+#
+# Copyright (c) 2016-2025 Objectionary.com
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included
+# in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+---
+line: 4
+message: |-
+  [4:4] error: 'Comment here is prohibited'
+      # The first comment is prohibited
+      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+  [5:4] error: 'Comment here is prohibited'
+      # The second comment is prohibited
+      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+  [7:6] error: 'Comment here is prohibited'
+        # The third comment is prohibited
+        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+input: |
+  # No comments
+  [args] > app
+    stdout > @
+      # The first comment is prohibited
+      # The second comment is prohibited
+      sprintwf
+        # The third comment is prohibited
+        "hello"