From d5ab00079e008d5c8ab17eacfa5b81822c2d24e3 Mon Sep 17 00:00:00 2001
From: maxonfjvipon <mtrunnikov@gmail.com>
Date: Sun, 8 Dec 2024 23:55:28 +0300
Subject: [PATCH] fix(#3569): prohibit numbers in attribute-name in XSD

---
 .../resources/org/eolang/maven/phi/to-phi.xsl | 48 ++++++++++---------
 .../org/eolang/maven/pre/to-java.xsl          |  7 ++-
 .../eolang/maven/unphi/normalize-bytes.xsl    |  2 +-
 .../org/eolang/maven/unphi/wrap-bytes.xsl     |  2 +-
 .../org/eolang/maven/phi/yaml/bindings.yaml   |  4 +-
 .../maven/phi/yaml/inline-bindings.yaml       | 33 +++++++++++++
 .../org/eolang/maven/unphi/bindings.yaml      |  4 +-
 .../maven/unphi/inline-application.yaml       | 14 +++---
 .../maven/unphi/termination-with-tail.yaml    |  2 +-
 .../maven/unphi/with-anonym-abstract.yaml     |  2 +-
 .../org/eolang/maven/unphi/with-data.yaml     |  2 +-
 .../java/org/eolang/parser/XeEoListener.java  |  4 +-
 .../java/org/eolang/parser/XePhiListener.java |  8 ++--
 eo-parser/src/main/resources/XMIR.xsd         |  2 +-
 .../org/eolang/parser/xmir-to-eo-reversed.xsl | 10 +++-
 .../org/eolang/parser/xmir-to-eo.xsl          | 10 +++-
 .../org/eolang/parser/packs/full-syntax.yaml  |  4 +-
 .../syntax/bound-reversed-application.yaml    |  4 +-
 .../parser/samples/explicit-bindings.yaml     | 39 +++++++++++++++
 19 files changed, 146 insertions(+), 55 deletions(-)
 create mode 100644 eo-maven-plugin/src/test/resources/org/eolang/maven/phi/yaml/inline-bindings.yaml
 create mode 100644 eo-parser/src/test/resources/org/eolang/parser/samples/explicit-bindings.yaml

diff --git a/eo-maven-plugin/src/main/resources/org/eolang/maven/phi/to-phi.xsl b/eo-maven-plugin/src/main/resources/org/eolang/maven/phi/to-phi.xsl
index 95f79fc28d..ed66e29d96 100644
--- a/eo-maven-plugin/src/main/resources/org/eolang/maven/phi/to-phi.xsl
+++ b/eo-maven-plugin/src/main/resources/org/eolang/maven/phi/to-phi.xsl
@@ -27,9 +27,7 @@ SOFTWARE.
   <xsl:output encoding="UTF-8" method="text"/>
   <!-- Variables -->
   <xsl:variable name="aliases" select="program/metas/meta/part[last()]"/>
-  <xsl:variable name="number-pattern">
-    <xsl:value-of select="'^[0-9][1-9]*$'"/>
-  </xsl:variable>
+  <xsl:variable name="number-pattern" select="'^[0-9][1-9]*$'"/>
   <xsl:variable name="xi">
     <select>ξ</select>
   </xsl:variable>
@@ -214,6 +212,28 @@ SOFTWARE.
       </xsl:otherwise>
     </xsl:choose>
   </xsl:function>
+  <!--
+    Try to get @as attribute from the object and convert to number, if @as is absent - return position
+  -->
+  <xsl:function name="eo:element-binding">
+    <xsl:param name="object"/>
+    <xsl:param name="position"/>
+    <xsl:choose>
+      <xsl:when test="$object/@as">
+        <xsl:choose>
+          <xsl:when test="starts-with($object/@as, $alpha)">
+            <xsl:value-of select="number(substring-after($object/@as, $alpha))"/>
+          </xsl:when>
+          <xsl:otherwise>
+            <xsl:value-of select="$object/@as"/>
+          </xsl:otherwise>
+        </xsl:choose>
+      </xsl:when>
+      <xsl:otherwise>
+        <xsl:value-of select="$position"/>
+      </xsl:otherwise>
+    </xsl:choose>
+  </xsl:function>
   <!--
     CHECKS IF APPLICATION ARGUMENTS IS RIGHT ORDER WITH ALPHAS, e.g.
     α0 -> a, α1 -> b, ..., αN -> z
@@ -221,27 +241,9 @@ SOFTWARE.
   <xsl:function name="eo:is-ordered">
     <xsl:param name="current"/>
     <xsl:param name="position"/>
-    <xsl:variable name="current-pos">
-      <xsl:choose>
-        <xsl:when test="$current/@as">
-          <xsl:value-of select="$current/@as"/>
-        </xsl:when>
-        <xsl:otherwise>
-          <xsl:value-of select="$position - 1"/>
-        </xsl:otherwise>
-      </xsl:choose>
-    </xsl:variable>
+    <xsl:variable name="current-pos" select="eo:element-binding($current, $position - 1)"/>
     <xsl:variable name="next" select="$current/following-sibling::o[1]"/>
-    <xsl:variable name="next-pos">
-      <xsl:choose>
-        <xsl:when test="$next/@as">
-          <xsl:value-of select="$next/@as"/>
-        </xsl:when>
-        <xsl:otherwise>
-          <xsl:value-of select="$position"/>
-        </xsl:otherwise>
-      </xsl:choose>
-    </xsl:variable>
+    <xsl:variable name="next-pos" select="eo:element-binding($next, $position)"/>
     <xsl:choose>
       <xsl:when test="matches($current-pos, $number-pattern)">
         <xsl:choose>
diff --git a/eo-maven-plugin/src/main/resources/org/eolang/maven/pre/to-java.xsl b/eo-maven-plugin/src/main/resources/org/eolang/maven/pre/to-java.xsl
index 3f98d9987d..b4432df20f 100644
--- a/eo-maven-plugin/src/main/resources/org/eolang/maven/pre/to-java.xsl
+++ b/eo-maven-plugin/src/main/resources/org/eolang/maven/pre/to-java.xsl
@@ -36,6 +36,9 @@ SOFTWARE.
   <xsl:variable name="PHI">
     <xsl:text>φ</xsl:text>
   </xsl:variable>
+  <xsl:variable name="ALPHA">
+    <xsl:text>α</xsl:text>
+  </xsl:variable>
   <!-- FUNCTIONS -->
   <!-- EOL -->
   <xsl:function name="eo:eol">
@@ -453,8 +456,8 @@ SOFTWARE.
       <xsl:choose>
         <xsl:when test="@as">
           <xsl:choose>
-            <xsl:when test="matches(@as,'^[0-9]+$')">
-              <xsl:value-of select="eo:attr-name(@as)"/>
+            <xsl:when test="starts-with(@as, $ALPHA)">
+              <xsl:value-of select="eo:attr-name(substring-after(@as, $ALPHA))"/>
             </xsl:when>
             <xsl:otherwise>
               <xsl:text>"</xsl:text>
diff --git a/eo-maven-plugin/src/main/resources/org/eolang/maven/unphi/normalize-bytes.xsl b/eo-maven-plugin/src/main/resources/org/eolang/maven/unphi/normalize-bytes.xsl
index 19c08d4ede..16b868cb6b 100644
--- a/eo-maven-plugin/src/main/resources/org/eolang/maven/unphi/normalize-bytes.xsl
+++ b/eo-maven-plugin/src/main/resources/org/eolang/maven/unphi/normalize-bytes.xsl
@@ -35,7 +35,7 @@ SOFTWARE.
   -->
   <xsl:import href="/org/eolang/parser/_funcs.xsl"/>
   <xsl:output encoding="UTF-8" method="xml"/>
-  <xsl:template match="o[eo:abstract(.) and @as='0' and eo:has-data(.)]">
+  <xsl:template match="o[eo:abstract(.) and @as='α0' and eo:has-data(.)]">
     <xsl:value-of select="text()"/>
   </xsl:template>
   <xsl:template match="node()|@*">
diff --git a/eo-maven-plugin/src/main/resources/org/eolang/maven/unphi/wrap-bytes.xsl b/eo-maven-plugin/src/main/resources/org/eolang/maven/unphi/wrap-bytes.xsl
index 4c99409d76..44b8c3672b 100644
--- a/eo-maven-plugin/src/main/resources/org/eolang/maven/unphi/wrap-bytes.xsl
+++ b/eo-maven-plugin/src/main/resources/org/eolang/maven/unphi/wrap-bytes.xsl
@@ -36,7 +36,7 @@ SOFTWARE.
       <xsl:attribute name="base">org.eolang.bytes</xsl:attribute>
       <xsl:attribute name="name" select="@name"/>
       <xsl:element name="o">
-        <xsl:attribute name="as" select="0"/>
+        <xsl:attribute name="as" select="'α0'"/>
         <xsl:value-of select="text()"/>
       </xsl:element>
     </xsl:element>
diff --git a/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/yaml/bindings.yaml b/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/yaml/bindings.yaml
index 6c5958e205..33f2c29bf2 100644
--- a/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/yaml/bindings.yaml
+++ b/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/yaml/bindings.yaml
@@ -26,6 +26,7 @@ input: |
     [z]:abs
       w > @
     5:five
+    "hello":3
 phi: |-
   {
     ⟦
@@ -35,7 +36,8 @@ phi: |-
           z ↦ ∅,
           φ ↦ Φ̇.w
         ⟧,
-        five ↦ 5
+        five ↦ 5,
+        α3 ↦ "hello"
       )
     ⟧
   }
diff --git a/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/yaml/inline-bindings.yaml b/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/yaml/inline-bindings.yaml
new file mode 100644
index 0000000000..d324a8290e
--- /dev/null
+++ b/eo-maven-plugin/src/test/resources/org/eolang/maven/phi/yaml/inline-bindings.yaml
@@ -0,0 +1,33 @@
+# 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.
+---
+input: |
+  x > xyz
+    "f":0
+    "s":1
+    "t":2
+phi: |-
+  {
+    ⟦
+      xyz ↦ Φ̇.x("f", "s", "t")
+    ⟧
+  }
diff --git a/eo-maven-plugin/src/test/resources/org/eolang/maven/unphi/bindings.yaml b/eo-maven-plugin/src/test/resources/org/eolang/maven/unphi/bindings.yaml
index 93f52ddd3f..4a86fb4d74 100644
--- a/eo-maven-plugin/src/test/resources/org/eolang/maven/unphi/bindings.yaml
+++ b/eo-maven-plugin/src/test/resources/org/eolang/maven/unphi/bindings.yaml
@@ -26,8 +26,8 @@ asserts:
   - //o[@base='.x' and @name='xyz']/o[not(@base) and @as='abs']/o[@name='z' and @base='∅']
   - //o[@base='.x' and @name='xyz']/o[not(@base) and @as='abs']/o[@base='.w' and @name='@']/o[@base='.eolang']/o[@base='.org']/o[@base='Q']
   - //o[@base='.x' and @name='xyz']/o[@base='.int' and @as='five']/o[@base='.eolang']/o[@base='.org']/o[@base='Q']
-  - //o[@base='.x' and @name='xyz']/o[@base='.int' and @as='five']/o[@as='0' and @base='.bytes']/o[@base='.eolang']/o[@base='.org']/o[@base='Q']
-  - //o[@base='.x' and @name='xyz']/o[@base='.int' and @as='five']/o[@as='0' and @base='.bytes' and text()!='']
+  - //o[@base='.x' and @name='xyz']/o[@base='.int' and @as='five']/o[@as='α0' and @base='.bytes']/o[@base='.eolang']/o[@base='.org']/o[@base='Q']
+  - //o[@base='.x' and @name='xyz']/o[@base='.int' and @as='five']/o[@as='α0' and @base='.bytes' and text()!='']
 phi: |-
   {
     ⟦
diff --git a/eo-maven-plugin/src/test/resources/org/eolang/maven/unphi/inline-application.yaml b/eo-maven-plugin/src/test/resources/org/eolang/maven/unphi/inline-application.yaml
index 09d81984ce..2ab97c9b4e 100644
--- a/eo-maven-plugin/src/test/resources/org/eolang/maven/unphi/inline-application.yaml
+++ b/eo-maven-plugin/src/test/resources/org/eolang/maven/unphi/inline-application.yaml
@@ -22,13 +22,13 @@
 ---
 asserts:
   - //o[@base='.foo' and @name='xyz']/o[1][@base='Q']
-  - //o[@base='.foo' and @name='xyz']/o[@as='0' and @base='org.eolang.string']/o[@base='org.eolang.bytes' and text()='48-65-6C-6C-6F']
-  - //o[@base='.foo' and @name='xyz']/o[@as='1' and @base='org.eolang.string']/o[@base='org.eolang.bytes' and text()='77-6F-72-6C-64']
-  - //o[@base='.foo' and @name='xyz']/o[@as='2' and @base='.plus']/o[1][@base='org.eolang.number' and not(@as)]/o[@base='org.eolang.bytes' and text()='40-45-00-00-00-00-00-00']
-  - //o[@base='.foo' and @name='xyz']/o[@as='2' and @base='.plus']/o[@base='org.eolang.number' and @as='0']/o[@base='org.eolang.bytes' and text()='40-41-80-00-00-00-00-00']
-  - //o[@base='.foo' and @name='xyz']/o[@as='3' and @base='.some']/o[1][@base='org.eolang.number' and not(@as)]/o[@base='org.eolang.bytes' and text()='40-3F-19-99-99-99-99-9A']
-  - //o[@base='.foo' and @name='xyz']/o[@as='3' and @base='.some']/o[@base='.y' and @as='0']/o[1][@base='Q']
-  - //o[@base='.foo' and @name='xyz']/o[@as='3' and @base='.some']/o[@base='.y' and @as='0']/o[@base='org.eolang.number' and @as='0']/o[@base='org.eolang.bytes' and text()='40-26-00-00-00-00-00-00']
+  - //o[@base='.foo' and @name='xyz']/o[@as='α0' and @base='org.eolang.string']/o[@base='org.eolang.bytes' and text()='48-65-6C-6C-6F']
+  - //o[@base='.foo' and @name='xyz']/o[@as='α1' and @base='org.eolang.string']/o[@base='org.eolang.bytes' and text()='77-6F-72-6C-64']
+  - //o[@base='.foo' and @name='xyz']/o[@as='α2' and @base='.plus']/o[1][@base='org.eolang.number' and not(@as)]/o[@base='org.eolang.bytes' and text()='40-45-00-00-00-00-00-00']
+  - //o[@base='.foo' and @name='xyz']/o[@as='α2' and @base='.plus']/o[@base='org.eolang.number' and @as='α0']/o[@base='org.eolang.bytes' and text()='40-41-80-00-00-00-00-00']
+  - //o[@base='.foo' and @name='xyz']/o[@as='α3' and @base='.some']/o[1][@base='org.eolang.number' and not(@as)]/o[@base='org.eolang.bytes' and text()='40-3F-19-99-99-99-99-9A']
+  - //o[@base='.foo' and @name='xyz']/o[@as='α3' and @base='.some']/o[@base='.y' and @as='α0']/o[1][@base='Q']
+  - //o[@base='.foo' and @name='xyz']/o[@as='α3' and @base='.some']/o[@base='.y' and @as='α0']/o[@base='org.eolang.number' and @as='α0']/o[@base='org.eolang.bytes' and text()='40-26-00-00-00-00-00-00']
 phi: |-
   {
     ⟦
diff --git a/eo-maven-plugin/src/test/resources/org/eolang/maven/unphi/termination-with-tail.yaml b/eo-maven-plugin/src/test/resources/org/eolang/maven/unphi/termination-with-tail.yaml
index 215b4f8135..724712c02d 100644
--- a/eo-maven-plugin/src/test/resources/org/eolang/maven/unphi/termination-with-tail.yaml
+++ b/eo-maven-plugin/src/test/resources/org/eolang/maven/unphi/termination-with-tail.yaml
@@ -22,7 +22,7 @@
 ---
 asserts:
   - /program/objects/o[@base='.m' and @name='x']/o[@base='org.eolang.error']
-  - /program/objects/o[@base='org.eolang.error' and @name='y']/o[@as='0' and @base='.x']/o[@base='$']
+  - /program/objects/o[@base='org.eolang.error' and @name='y']/o[@as='α0' and @base='.x']/o[@base='$']
 phi: |
   {
   	⟦
diff --git a/eo-maven-plugin/src/test/resources/org/eolang/maven/unphi/with-anonym-abstract.yaml b/eo-maven-plugin/src/test/resources/org/eolang/maven/unphi/with-anonym-abstract.yaml
index ae32135081..6fb5f7048d 100644
--- a/eo-maven-plugin/src/test/resources/org/eolang/maven/unphi/with-anonym-abstract.yaml
+++ b/eo-maven-plugin/src/test/resources/org/eolang/maven/unphi/with-anonym-abstract.yaml
@@ -22,7 +22,7 @@
 ---
 asserts:
   - //o[@name='test' and not(@base)]/o[@base='.plus' and @name='s']/o[position()=1 and not(@base) and not(@name)]
-  - //o[@name='test' and not(@base)]/o[@base='.plus' and @name='s']/o[position()>1 and @as='0' and @base='.int']/o[@base='.eolang']/o[@base='.org']/o[@base='Q']
+  - //o[@name='test' and not(@base)]/o[@base='.plus' and @name='s']/o[position()>1 and @as='α0' and @base='.int']/o[@base='.eolang']/o[@base='.org']/o[@base='Q']
 phi: |-
   {
     ⟦
diff --git a/eo-maven-plugin/src/test/resources/org/eolang/maven/unphi/with-data.yaml b/eo-maven-plugin/src/test/resources/org/eolang/maven/unphi/with-data.yaml
index 12dc8cba56..309df70268 100644
--- a/eo-maven-plugin/src/test/resources/org/eolang/maven/unphi/with-data.yaml
+++ b/eo-maven-plugin/src/test/resources/org/eolang/maven/unphi/with-data.yaml
@@ -22,5 +22,5 @@
 ---
 asserts:
   - //o[@name='five' and @base='.int']/o[@base='.eolang']
-  - //o[@name='five' and @base='.int']/o[@base='.bytes' and @as='0']
+  - //o[@name='five' and @base='.int']/o[@base='.bytes' and @as='α0']
 phi: "{⟦five ↦ Φ.org.eolang.int(α0 ↦ Φ.org.eolang.bytes(α0 ↦ ⟦Δ ⤍ 00-00-00-00-00-00-00-05⟧))⟧}"
diff --git a/eo-parser/src/main/java/org/eolang/parser/XeEoListener.java b/eo-parser/src/main/java/org/eolang/parser/XeEoListener.java
index 907913093c..d80d91974f 100644
--- a/eo-parser/src/main/java/org/eolang/parser/XeEoListener.java
+++ b/eo-parser/src/main/java/org/eolang/parser/XeEoListener.java
@@ -1142,10 +1142,8 @@ public void enterAs(final EoParser.AsContext ctx) {
         final String has;
         if (ctx.NAME() != null) {
             has = ctx.NAME().getText();
-        } else if (ctx.INT() != null) {
-            has = ctx.INT().getText();
         } else {
-            has = "^";
+            has = String.format("α%s", ctx.INT().getText());
         }
         this.objects.prop("as", has);
     }
diff --git a/eo-parser/src/main/java/org/eolang/parser/XePhiListener.java b/eo-parser/src/main/java/org/eolang/parser/XePhiListener.java
index 8c60f92aae..249f632e2f 100644
--- a/eo-parser/src/main/java/org/eolang/parser/XePhiListener.java
+++ b/eo-parser/src/main/java/org/eolang/parser/XePhiListener.java
@@ -237,10 +237,8 @@ public void enterAttribute(final PhiParser.AttributeContext ctx) {
             attr = "@";
         } else if (ctx.RHO() != null) {
             attr = "^";
-        } else if (ctx.LABEL() != null) {
-            attr = ctx.LABEL().getText();
-        } else if (ctx.ALPHA() != null) {
-            attr = ctx.ALPHA().getText().substring(1);
+        } else if (ctx.LABEL() != null || ctx.ALPHA() != null) {
+            attr = ctx.getText();
         } else {
             attr = "";
         }
@@ -335,7 +333,7 @@ public void enterJustObject(final PhiParser.JustObjectContext ctx) {
         final int index = this.alphas.peek();
         this.alphas.pop();
         this.alphas.push(index + 1);
-        this.attributes.push(String.valueOf(index));
+        this.attributes.push(String.format("α%d", index));
     }
 
     @Override
diff --git a/eo-parser/src/main/resources/XMIR.xsd b/eo-parser/src/main/resources/XMIR.xsd
index 8096ca8842..592eef3120 100644
--- a/eo-parser/src/main/resources/XMIR.xsd
+++ b/eo-parser/src/main/resources/XMIR.xsd
@@ -83,7 +83,7 @@ SOFTWARE.
       </xs:documentation>
     </xs:annotation>
     <xs:restriction base="xs:string">
-      <xs:pattern value="[0-9]+|@|[a-z][^ \n\t\r]*"/>
+      <xs:pattern value="α[0-9]+|@|[a-z][^ \n\t\r]*"/>
     </xs:restriction>
   </xs:simpleType>
   <xs:simpleType name="fqn">
diff --git a/eo-parser/src/main/resources/org/eolang/parser/xmir-to-eo-reversed.xsl b/eo-parser/src/main/resources/org/eolang/parser/xmir-to-eo-reversed.xsl
index 797660259b..99f36c1967 100644
--- a/eo-parser/src/main/resources/org/eolang/parser/xmir-to-eo-reversed.xsl
+++ b/eo-parser/src/main/resources/org/eolang/parser/xmir-to-eo-reversed.xsl
@@ -29,6 +29,7 @@ SOFTWARE.
   -->
   <xsl:import href="/org/eolang/parser/_funcs.xsl"/>
   <xsl:variable name="eol" select="'&#10;'"/>
+  <xsl:variable name="alpha" select="'α'"/>
   <xsl:variable name="comment">
     <xsl:text># No comments.</xsl:text>
     <xsl:value-of select="$eol"/>
@@ -125,7 +126,14 @@ SOFTWARE.
   <xsl:template match="o" mode="tail">
     <xsl:if test="@as">
       <xsl:text>:</xsl:text>
-      <xsl:value-of select="@as"/>
+      <xsl:choose>
+        <xsl:when test="starts-with(@as, $alpha)">
+          <xsl:value-of select="substring-after(@as, $alpha)"/>
+        </xsl:when>
+        <xsl:otherwise>
+          <xsl:value-of select="@as"/>
+        </xsl:otherwise>
+      </xsl:choose>
     </xsl:if>
     <xsl:if test="@name">
       <xsl:text> &gt; </xsl:text>
diff --git a/eo-parser/src/main/resources/org/eolang/parser/xmir-to-eo.xsl b/eo-parser/src/main/resources/org/eolang/parser/xmir-to-eo.xsl
index 05479efa6c..6249751de5 100644
--- a/eo-parser/src/main/resources/org/eolang/parser/xmir-to-eo.xsl
+++ b/eo-parser/src/main/resources/org/eolang/parser/xmir-to-eo.xsl
@@ -29,6 +29,7 @@ SOFTWARE.
   -->
   <xsl:import href="/org/eolang/parser/_funcs.xsl"/>
   <xsl:variable name="eol" select="'&#10;'"/>
+  <xsl:variable name="alpha" select="'α'"/>
   <xsl:variable name="comment">
     <xsl:text># No comments.</xsl:text>
     <xsl:value-of select="$eol"/>
@@ -141,7 +142,14 @@ SOFTWARE.
   <xsl:template match="o" mode="tail">
     <xsl:if test="@as">
       <xsl:text>:</xsl:text>
-      <xsl:value-of select="@as"/>
+      <xsl:choose>
+        <xsl:when test="starts-with(@as, $alpha)">
+          <xsl:value-of select="substring-after(@as, $alpha)"/>
+        </xsl:when>
+        <xsl:otherwise>
+          <xsl:value-of select="@as"/>
+        </xsl:otherwise>
+      </xsl:choose>
     </xsl:if>
     <xsl:if test="@name">
       <xsl:text> &gt; </xsl:text>
diff --git a/eo-parser/src/test/resources/org/eolang/parser/packs/full-syntax.yaml b/eo-parser/src/test/resources/org/eolang/parser/packs/full-syntax.yaml
index 0ec8e22959..224e8a5d7e 100644
--- a/eo-parser/src/test/resources/org/eolang/parser/packs/full-syntax.yaml
+++ b/eo-parser/src/test/resources/org/eolang/parser/packs/full-syntax.yaml
@@ -30,8 +30,8 @@ asserts:
   - //o[@base='string']
   - //o[@name='hello' and @const]
   - //o[@as='i']
-  - //o[@as='1']
-  - //o[@as='0']
+  - //o[@as='α1']
+  - //o[@as='α0']
   - //o[@base='.five']
   - //objects[not(.//o[@name=''])]
   - //o[@atom and @name='atom' and count(o)=2 and o[@name='a']]
diff --git a/eo-parser/src/test/resources/org/eolang/parser/packs/syntax/bound-reversed-application.yaml b/eo-parser/src/test/resources/org/eolang/parser/packs/syntax/bound-reversed-application.yaml
index 0f3d25fba0..7624d2a118 100644
--- a/eo-parser/src/test/resources/org/eolang/parser/packs/syntax/bound-reversed-application.yaml
+++ b/eo-parser/src/test/resources/org/eolang/parser/packs/syntax/bound-reversed-application.yaml
@@ -23,8 +23,8 @@
 sheets: [ ]
 asserts:
   - /program[not(errors)]
-  - //o[@base='.if' and o[@base='string' and @as='0']]
-  - //o[@base='.if' and o[@base='string' and @as='1']]
+  - //o[@base='.if' and o[@base='string' and @as='α0']]
+  - //o[@base='.if' and o[@base='string' and @as='α1']]
   - //o[@base='.if' and o[@base='number' and @as='a']]
   - //o[@base='.if' and o[@base='number' and @as='b']]
 input: |
diff --git a/eo-parser/src/test/resources/org/eolang/parser/samples/explicit-bindings.yaml b/eo-parser/src/test/resources/org/eolang/parser/samples/explicit-bindings.yaml
new file mode 100644
index 0000000000..bf1328917d
--- /dev/null
+++ b/eo-parser/src/test/resources/org/eolang/parser/samples/explicit-bindings.yaml
@@ -0,0 +1,39 @@
+# 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.
+---
+origin: |
+  sprintf
+    "Hello %d, %f":text
+    42:1
+    12.3:2
+
+straight: |
+  sprintf
+    "Hello %d, %f":text
+    42:1
+    12.3:2
+
+reversed: |
+  sprintf
+    "Hello %d, %f":text
+    42:1
+    12.3:2