I ran into a similar issue and also assumed that nested if-statements wasn't supported. Looking at the l3vpn.xml file you referenced I can see that this was incorrect. It might just be a limitation of how or where you can use if statements. Using the same l3vpn.xml file we have this snippet:
<interface xmlns="http://tail-f.com/ned/cisco-ios-xr">
<?if {starts-with($PE_INT_NAME,'GigabitEthernet')}?>
<GigabitEthernet-subinterface>
<GigabitEthernet>
<id>{substring($PE_INT_NAME,16)}.{$VLAN_ID}</id>
<description>Link to CE / {$CE} - {$CE_INT_NAME}</description>
<ipv4>
<address>
<ip>{$LINK_PE_ADR}</ip>
<mask>{$LINK_MASK}</mask>
</address>
</ipv4>
<vrf>{/name}</vrf>
<encapsulation>
<dot1q>
<vlan-id>{$VLAN_ID}</vlan-id>
</dot1q>
</encapsulation>
<service-policy>
<output>
<name>{/name}-{$CE}</name>
</output>
</service-policy>
</GigabitEthernet>
</GigabitEthernet-subinterface>
<?end?>
<?if {starts-with($PE_INT_NAME,'TenGigE')}?>
<TenGigE-subinterface>
<TenGigE>
<id>{substring($PE_INT_NAME,8)}.{$VLAN_ID}</id>
<description>Link to CE / {$CE} - {$CE_INT_NAME}</description>
<ipv4>
<address>
<ip>{$LINK_PE_ADR}</ip>
<mask>{$LINK_MASK}</mask>
</address>
</ipv4>
<vrf>{/name}</vrf>
<encapsulation>
<dot1q>
<vlan-id>{$VLAN_ID}</vlan-id>
</dot1q>
</encapsulation>
<service-policy>
<output>
<name>{/name}-{$CE}</name>
</output>
</service-policy>
</TenGigE>
</TenGigE-subinterface>
<?end?>
</interface>
In the above template, we see identical definitions for Gigabit and TenGigabit interfaces. In a template, we might also have Bundle-Ether or 100Gb interfaces. It doesn't seem very efficient to have to redefine every snippet for each interface type. Granted this part of the code is short in this specific template but it can be much longer. The end result is more code to test based on conditional logic where we need to check for more interface types and make sure that the configuration within the snippets is synced.
I would like to be able to do something like this instead:
<interface xmlns="http://tail-f.com/ned/cisco-ios-xr">
<?if {starts-with($PE_INT_NAME,'GigabitEthernet') or starts-with($PE_INT_NAME,'TenGigE')}?>
<?if {starts-with($PE_INT_NAME,'GigabitEthernet')}?>
<GigabitEthernet-subinterface>
<GigabitEthernet>
<?end?>
<?if {starts-with($PE_INT_NAME,'TenGigE')}?>
<TenGigE-subinterface>
<TenGigE>
<?end?>
<id>{substring($PE_INT_NAME,16)}.{$VLAN_ID}</id>
<description>Link to CE / {$CE} - {$CE_INT_NAME}</description>
<ipv4>
<address>
<ip>{$LINK_PE_ADR}</ip>
<mask>{$LINK_MASK}</mask>
</address>
</ipv4>
<vrf>{/name}</vrf>
<encapsulation>
<dot1q>
<vlan-id>{$VLAN_ID}</vlan-id>
</dot1q>
</encapsulation>
<service-policy>
<output>
<name>{/name}-{$CE}</name>
</output>
</service-policy>
<?if {starts-with($PE_INT_NAME,'GigabitEthernet')}?>
</GigabitEthernet>
</GigabitEthernet-subinterface>
<?end?>
<?if {starts-with($PE_INT_NAME,'TenGigE')}?>
</TenGigE>
</TenGigE-subinterface>
<?end?>
<?end?>
</interface>
The above template produces the same error as Johnny described:
reload-result {
package l3vpn
result false
info [l3vpn.xml:147 Processing instruction is unexpected here.]
}
<?if {starts-with($PE_INT_NAME,'GigabitEthernet') or starts-with($PE_INT_NAME,'TenGigE')}?>
<?if {starts-with($PE_INT_NAME,'GigabitEthernet')}?>
<GigabitEthernet-subinterface>
<GigabitEthernet>
<?end?> <--- Line 147
So, perhaps a better question would be what are the limitations of using the if-statement and how can it currently be used?
