bug(#3768): phi can be void

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

@@ -134,6 +134,7 @@ voids
 
 // Void attribute
 void: NAME
+    | PHI
     ;
 
 // Type of atom

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

@@ -51,6 +51,7 @@ public TrCanonical() {
                         new TrLogged(
                             new TrJoined<>(
                                 new TrClasspath<>(
+                                    "/org/eolang/parser/move-voids-up.xsl",
                                     "/org/eolang/parser/validate-before-stars.xsl",
                                     "/org/eolang/parser/resolve-before-star.xsl"
                                 ).back(),

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

@@ -334,7 +334,19 @@ public void exitVoids(final EoParser.VoidsContext ctx) {
 
     @Override
     public void enterVoid(final EoParser.VoidContext ctx) {
-        this.startObject(ctx).prop("name", ctx.NAME().getText()).prop("base", "∅");
+        this.startObject(ctx);
+        final String name;
+        if (ctx.NAME() != null) {
+            name = ctx.NAME().getText();
+        } else if (ctx.PHI() != null) {
+            name = ctx.PHI().getText();
+        } else {
+            name = "";
+        }
+        if (!name.isEmpty()) {
+            this.objects.prop("name", name);
+        }
+        this.objects.prop("base", "∅");
     }
 
     @Override

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

@@ -233,7 +233,7 @@ public String toPhi(final boolean conservative) {
      */
     public String toSaltyPhi() {
         return this.converted(
-            Xmir.FOR_PHI, "/org/eolang/parser/phi/to-phi-no-sugar.xsl", "program/phi/text()"
+            Xmir.FOR_PHI, "/org/eolang/parser/phi/to-salty-phi.xsl", "program/phi/text()"
         );
     }
 

eo-parser/src/main/resources/org/eolang/parser/move-voids-up.xsl

@@ -0,0 +1,53 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+The MIT License (MIT)
+
+Copyright (c) 2016-2024 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.
+-->
+<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:eo="https://www.eolang.org" id="move-voids-up" version="2.0">
+  <!--
+  Move void attributes on top
+  -->
+  <xsl:import href="/org/eolang/parser/_funcs.xsl"/>
+  <xsl:output encoding="UTF-8" method="xml"/>
+  <xsl:template match="o[count(o)&gt;0]">
+    <xsl:apply-templates select="." mode="with-attrs"/>
+  </xsl:template>
+  <xsl:template match="o[count(o[eo:void(.)])&gt;0 and count(o[not(eo:void(.))])&gt;0]" mode="with-attrs">
+    <xsl:apply-templates select="." mode="with-diff-attrs"/>
+  </xsl:template>
+  <xsl:template match="o[o[not(eo:void(.))]/following-sibling::o[eo:void(.)]]" mode="with-diff-attrs">
+    <xsl:element name="o">
+      <xsl:apply-templates select="@*"/>
+      <xsl:for-each select="o[eo:void(.)]">
+        <xsl:copy-of select="."/>
+      </xsl:for-each>
+      <xsl:for-each select="o[not(eo:void(.))]">
+        <xsl:apply-templates select="."/>
+      </xsl:for-each>
+    </xsl:element>
+  </xsl:template>
+  <xsl:template match="node()|@*" mode="#all">
+    <xsl:copy>
+      <xsl:apply-templates select="node()|@*"/>
+    </xsl:copy>
+  </xsl:template>
+</xsl:stylesheet>

eo-parser/src/main/resources/org/eolang/parser/phi/to-phi.xsl

@@ -342,7 +342,7 @@ SOFTWARE.
   </xsl:template>
   <!-- Void attribute -->
   <xsl:template match="o[eo:void(.)]">
-    <xsl:value-of select="@name"/>
+    <xsl:value-of select="eo:specials(@name, true())"/>
     <xsl:value-of select="$arrow"/>
     <xsl:value-of select="$empty"/>
   </xsl:template>
@@ -354,7 +354,7 @@ SOFTWARE.
         <xsl:value-of select="eo:comma(position(), -1)"/>
         <xsl:value-of select="$space"/>
       </xsl:if>
-      <xsl:value-of select="@name"/>
+      <xsl:value-of select="eo:specials(@name, true())"/>
     </xsl:for-each>
     <xsl:value-of select="$crb"/>
   </xsl:template>

eo-parser/src/main/resources/org/eolang/parser/phi/to-phi-no-sugar.xsl → eo-parser/src/main/resources/org/eolang/parser/phi/to-salty-phi.xsl

@@ -22,7 +22,7 @@ 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.
 -->
-<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:eo="https://www.eolang.org" id="to-phi-no-sugar" version="2.0">
+<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:eo="https://www.eolang.org" id="to-salty-phi" version="2.0">
   <xsl:import href="/org/eolang/parser/_funcs.xsl"/>
   <xsl:output encoding="UTF-8" method="text"/>
   <!-- Variables -->
@@ -211,8 +211,8 @@ SOFTWARE.
     </xsl:for-each>
   </xsl:template>
   <!-- Void attribute -->
-  <xsl:template match="o[@base=$empty]">
-    <xsl:value-of select="./@name"/>
+  <xsl:template match="o[eo:void(.)]">
+    <xsl:value-of select="eo:specials(@name, true())"/>
     <xsl:value-of select="$arrow"/>
     <xsl:value-of select="$empty"/>
   </xsl:template>
@@ -241,7 +241,7 @@ SOFTWARE.
     </xsl:choose>
   </xsl:template>
   <!-- Just object -->
-  <xsl:template match="o[@base and @base!=$empty]">
+  <xsl:template match="o[@base and not(eo:void(.))]">
     <xsl:param name="tabs"/>
     <xsl:param name="package"/>
     <xsl:if test="@name">

eo-parser/src/test/resources/org/eolang/parser/eo-packs/full-syntax.yaml

@@ -54,6 +54,15 @@ input: |
   # No comments.
   [tt a] > atom /int
 
+  # This unit test is supposed to check the functionality of the corresponding object.
+  [] > with-void-phi
+    [@] > x
+      "Hello" > hello
+    x 5 > five
+    and. > @
+      (five.plus 5).eq 10
+      five.hello.eq "Hello"
+
   # This is very good object
   # No comments.
   [x] > first

eo-runtime/src/test/resources/org/eolang/snippets/parenting.yaml → eo-parser/src/test/resources/org/eolang/parser/eo-packs/move-voids-up.yaml

@@ -20,20 +20,18 @@
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 # SOFTWARE.
 ---
-file: org/eolang/snippets/parenting.eo
-out:
-  - ".*123.*"
-args: [ "org.eolang.snippets.parenting", "123" ]
-eo: |
-  +package org.eolang.snippets
-  +alias org.eolang.io.stdout
-
+sheets: [ ]
+asserts:
+  - /program[not(errors)]
+  - /program/objects/o[@name='foo' and o[@name='x']/following-sibling::o[@name='@']]
+  - /program/objects/o[@name='bar' and o[@name='x']/following-sibling::o[@name='@']/o[@name='y']/following-sibling::o[@name='@']]
+input: |
   # No comments.
-  [args] > parenting
-    "The code snippet that checks parent's args" > description
+  [x] > app
+    5 > y
+
+  # Foo.
+  "Hello" > [x] > foo
 
-    # No comments.
-    [] > take
-      ^.args.at 0 > @
-    stdout > @
-      take
+  # Bar.
+  z > [y] > [x] > bar

eo-runtime/src/test/resources/org/eolang/snippets/simple-horizontal.yaml → eo-parser/src/test/resources/org/eolang/parser/phi-packs/with-void-phi.yaml

@@ -20,13 +20,18 @@
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 # SOFTWARE.
 ---
-out:
-  - ".*Hello, Jeff!.*"
-file: org/eolang/snippets/simple-horizontal.eo
-args: [ "org.eolang.snippets.simple-horizontal" ]
-eo: |
-  +package org.eolang.snippets
-  +alias org.eolang.io.stdout
-
-  # No comments.
-  [args] (stdout "Hello, Jeff!" > @) > simple-horizontal
+input: |-
+  # Foo.
+  [@] > foo
+sweet: |-
+  {⟦
+    foo(φ) ↦ ⟦⟧
+  ⟧}
+salty: |-
+  {
+    ⟦
+      foo ↦ ⟦
+        φ ↦ ∅
+      ⟧
+    ⟧
+  }

eo-parser/src/test/resources/org/eolang/parser/phi-syntax/all-the-basics.phi

@@ -33,5 +33,7 @@
   inline-voids(text, α0, φ) ↦ ⟦ ⟧,
   empty-inline-voids() ↦ ⟦
     num ↦ 42
-  ⟧
+  ⟧,
+  with-void-phi-sweet(φ) ↦ ⟦⟧,
+  with-void-phi-salty ↦ ⟦ φ ↦ ∅ ⟧
 ⟧}

eo-runtime/src/main/java/org/eolang/PhDefault.java

@@ -49,7 +49,9 @@ public class PhDefault implements Phi, Cloneable {
     /**
      * Attribute name matcher.
      */
-    private static final Pattern SORTABLE = Pattern.compile("^[a-z].*$");
+    private static final Pattern SORTABLE = Pattern.compile(
+        String.format("^([a-z].*)|%s$", Attr.PHI)
+    );
 
     /**
      * Attributes nesting level.

eo-runtime/src/test/eo/org/eolang/runtime-tests.eo

@@ -335,6 +335,28 @@
         build 2 > @
     9
 
+# This unit test is supposed to check the functionality of the corresponding object.
+[] > with-void-phi
+  [@] > x
+    "Hello" > hello
+  x 5 > five
+  and. > @
+    (five.plus 5).eq 10
+    five.hello.eq "Hello"
+
+# This unit test is supposed to check the functionality of the corresponding object.
+[] (seq (* (five.eq 5) true) > @) (5 > five) > complex-horizontal
+
+# This unit test is supposed to check the functionality of the corresponding object.
+[] > vertical-bound-method
+  eq. > @
+    if.
+      true
+      "second":1
+      "first"
+      .as-bytes:0
+    "first"
+
 # Nesting blah test.
 [] > nesting-blah-test
   blah0 > @