function id() works in the xpath but not in the xsl

Hey I'm from Brazil. So, sorry for my english!

If I consult //jogoGrupo[1]/jogo[1]/selecao/id(@pais) in the xpath I get: Franca e Senegal. However I put this consult int the xsl <xsl:value-of select="//jogoGrupo[1]/jogo[1]/selecao/id(@pais)"/> and doesn't work.

I think the error is in the schema, is it right to declare pais as xs:idref in <selecao pais=s1>, somebody could help me?

XML:

<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="file:///C:/Users/Cesar%20Frantz/Desktop/XML/trabalhoxml.xsl"?>
<Bolaocopa xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="file:///C:/Users/Cesar%20Frantz/Desktop/XML/trabalhoxml.xsd">
	<grupos>
		<grupo tipo="A">
			<pais id="s1">Franca</pais>
			<pais id="s2">Senegal</pais>
			<pais id="s3">Uruguai</pais>
			<pais id="s4">Dinamarca</pais>
		</grupo>
		<grupo tipo="B">
			<pais id="s5">Espanha</pais>
			<pais id="s6">Paraguai</pais>
			<pais id="s7">Africa do Sul</pais>
			<pais id="s8">Eslovenia</pais>
		</grupo>
		<grupo tipo="C">
			<pais id="s9">Brasil</pais>
			<pais id="s10">Turquia</pais>
			<pais id="s11">China</pais>
			<pais id="s12">Costa Rica</pais>
		</grupo>
	</grupos>
	<jogos>
		<faseGrupos>
			<jogoGrupo id="a">
				<jogo numero="1">
					<selecao pais="s1">0</selecao>
					<selecao pais="s2">1</selecao>
				</jogo>
				<jogo numero="2">
					<selecao pais="s3">1</selecao>
					<selecao pais="s4">2</selecao>
				</jogo>
				<jogo numero="3">
					<selecao pais="s4">1</selecao>
					<selecao pais="s2">1</selecao>
				</jogo>
				<jogo numero="4">
					<selecao pais="s3">0</selecao>
					<selecao pais="s1">0</selecao>
				</jogo>
				<jogo numero="5">
					<selecao pais="s4">2</selecao>
					<selecao pais="s1">0</selecao>
				</jogo>
				<jogo numero="6">
					<selecao pais="s2">3</selecao>
					<selecao pais="s3">3</selecao>
				</jogo>
			</jogoGrupo>
			<jogoGrupo id="b">
				<jogo numero="1">
					<selecao pais="s6">2</selecao>
					<selecao pais="s7">2</selecao>
				</jogo>
				<jogo numero="2">
					<selecao pais="s5">3</selecao>
					<selecao pais="s8">1</selecao>
				</jogo>
				<jogo numero="3">
					<selecao pais="s5">3</selecao>
					<selecao pais="s6">1</selecao>
				</jogo>
				<jogo numero="4">
					<selecao pais="s7">1</selecao>
					<selecao pais="s8">0</selecao>
				</jogo>
				<jogo numero="5">
					<selecao pais="s7">2</selecao>
					<selecao pais="s5">3</selecao>
				</jogo>
				<jogo numero="6">
					<selecao pais="s8">1</selecao>
					<selecao pais="s6">3</selecao>
				</jogo>
			</jogoGrupo>
			<jogoGrupo id="c">
				<jogo numero="1">
					<selecao pais="s9">2</selecao>
					<selecao pais="s10">1</selecao>
				</jogo>
				<jogo numero="2">
					<selecao pais="s11">0</selecao>
					<selecao pais="s12">2</selecao>
				</jogo>
				<jogo numero="3">
					<selecao pais="s9">4</selecao>
					<selecao pais="s11">0</selecao>
				</jogo>
				<jogo numero="4">
					<selecao pais="s12">1</selecao>
					<selecao pais="s10">1</selecao>
				</jogo>
				<jogo numero="5">
					<selecao pais="s12">2</selecao>
					<selecao pais="s9">5</selecao>
				</jogo>
				<jogo numero="6">
					<selecao pais="s10">3</selecao>
					<selecao pais="s11">0</selecao>
				</jogo>
			</jogoGrupo>
		</faseGrupos>
	</jogos>
</Bolaocopa>

XSL

SCHEMA:

<?xml version="1.0" encoding="UTF-8"?>

<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified" attributeFormDefault="unqualified">
	<xs:element name="Bolaocopa">
		<xs:annotation>
			<xs:documentation>Comment describing your root element</xs:documentation>
		</xs:annotation>
		<xs:complexType>
			<xs:sequence>
				<xs:element name="grupos">
					<xs:complexType>
						<xs:sequence>
							<xs:element name="grupo" maxOccurs="unbounded">
								<xs:complexType>
									<xs:sequence>
										<xs:element name="pais" minOccurs="1" maxOccurs="unbounded">
											<xs:complexType>
												<xs:simpleContent>
													<xs:extension base="xs:string">
														<xs:attribute name="id" type="xs:ID"/>
													</xs:extension>
												</xs:simpleContent>
											</xs:complexType>
										</xs:element>
									</xs:sequence>
									<xs:attribute name="tipo" type="xs:string"/>
								</xs:complexType>
							</xs:element>
						</xs:sequence>
					</xs:complexType>
				</xs:element>
				<xs:element name="jogos">
					<xs:complexType>
						<xs:sequence>
							<xs:element name="faseGrupos">
								<xs:complexType>
									<xs:sequence>
										<xs:element name="jogoGrupo" maxOccurs="unbounded">
											<xs:complexType>
												<xs:sequence>
													<xs:element name="jogo" maxOccurs="unbounded">
														<xs:complexType>
															<xs:sequence>
																<xs:element name="selecao" maxOccurs="unbounded">
																	<xs:complexType>
																		<xs:simpleContent>
																			<xs:extension base="xs:integer">
																				<xs:attribute name="pais" type="xs:IDREF"/>
																			</xs:extension>
																		</xs:simpleContent>
																	</xs:complexType>
																</xs:element>
															</xs:sequence>
															<xs:attribute name="numero" type="xs:integer"/>
														</xs:complexType>
													</xs:element>
												</xs:sequence>
												<xs:attribute name="id" type="xs:ID"/>
											</xs:complexType>
										</xs:element>
									</xs:sequence>
								</xs:complexType>
							</xs:element>
						</xs:sequence>
					</xs:complexType>
				</xs:element>
			</xs:sequence>
		</xs:complexType>
	</xs:element>
</xs:schema>

I think the error is in the schema, is it right to declare pais as xs:idref in <selecao pais=s1>, somebody could help me?

There is nothing wrong with the schema. It is just fine to declare pais attribute of selecao as xs:IDREF, you don't have to worry about it. If you define it as so xs:string (taking the most liberal view point), you just sacrifice some tighter constraint during validation: but as far as the schema-aware xslt processor is concerned, when you use fn:id(), it will automatically cast the argument into xs:IDREFS. So as long as those strings are of good format such as no whitespace inside, you could get away with unpredictable results as space would be looked as separator of some IDREF's. In simple term, it is just fine to have it as xs:IDREF.

fn:id() works just fine in xslt 2.0.

Now, what is the problem with your xslt? The problem is that you have not imported the schema to it. The consequence of it is that the xslt processor will fall back to it basic version, rather than being schema-aware and hence fn:id() has no place to do with it as it won't recognize who-is-who xs:ID or xs:IDREF. Or in some technical twist, the is-id property is not populated in the data model.

Furthermore, you can take full schema-awareness to stop xslt to output anything at all, which is often most damaging and non-sense, if the xml is invalid. This is realized in the template I add to it matching the loosely document-node(). This is how you can protect the application from this fallout.

<?xml version="1.0" encoding="ISO-8859-1"?>   

<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
    <xsl:output method="html" omit-xml-declaration="yes" encoding="ISO-8859-1" indent="yes" />
    <xsl:import-schema schema-location="file:///C:/Users/Cesar%20Frantz/Desktop/XML/trabalhoxml.xsd" />
    <xsl:template match="document-node(schema-element(Bolaocopa))">   
        <html>   
            <head>   
                <title> Bolão da COPA DO MUNDO - Cesar Frantz e Douglas Haubert</title>   
            </head>   
            <body>   
                   
                    <xsl:value-of select="//jogoGrupo[1]/jogo[1]/selecao/id(@pais)"/>   
                               
            </body>   
               
        </html>   
    </xsl:template>   
    
    <xsl:template match="document-node()">
        <xsl:message terminate="yes">Source document is not a Bolaocopa.</xsl:message>
    </xsl:template>
</xsl:stylesheet>

Like that, the application would be quite safe guarding against invalidate xml.