global: variable names are CamelCase

            ___  _         ___     __
           / _ )(_)__ _   / _/__ _/ /_
          / _  / / _ `/  / _/ _ `/ __/
         /____/_/\_, /  /_/ \_,_/\__/
 _       __     /___/       _             __
| |     / /___ __________  (_)___  ____ _/ /
| | /| / / __ `/ ___/ __ \/ / __ \/ __ `/ /
| |/ |/ / /_/ / /  / / / / / / / / /_/ /_/
|__/|__/\__,_/_/  /_/ /_/_/_/ /_/\__, (_)
                                /____/

RouterOS has some odd behavior when it comes to variable names. Let's
have a look at the interfaces:

[admin@MikroTik] > / interface print where name=en1
Flags: D - dynamic, X - disabled, R - running, S - slave
 #     NAME                                TYPE       ACTUAL-MTU L2MTU
 0  RS en1                                 ether            1500  1598

That looks ok. Now we use a script:

{ :local interface "en1";
  / interface print where name=$interface; }

And the result...

[admin@MikroTik] > { :local interface "en1";
{...   / interface print where name=$interface; }
Flags: D - dynamic, X - disabled, R - running, S - slave
 #     NAME                                TYPE       ACTUAL-MTU L2MTU
 0  RS en1                                 ether            1500  1598

... still looks ok.
We make a little modification to the script:

{ :local name "en1";
  / interface print where name=$name; }

And the result:

[admin@MikroTik] > { :local name "en1";
{...   / interface print where name=$name; }
Flags: D - dynamic, X - disabled, R - running, S - slave
 #     NAME                                TYPE       ACTUAL-MTU L2MTU
 0  RS en1                                 ether            1500  1598
 1   S en2                                 ether            1500  1598
 2   S en3                                 ether            1500  1598
 3   S en4                                 ether            1500  1598
 4   S en5                                 ether            1500  1598
 5  R  br-local                            bridge           1500  1598

Ups! The filter has no effect!
That happens whenever the variable name ($name) matches the property
name (name=).

And another modification:

{ :local type "en1";
  / interface print where name=$type; }

And the result:

[admin@MikroTik] > { :local type "en1";
{...   / interface print where name=$type; }
Flags: D - dynamic, X - disabled, R - running, S - slave
 #     NAME                                TYPE       ACTUAL-MTU L2MTU

Ups! Nothing?
Even if the variable name ($type) matches whatever property name (type=)
things go wrong.

The answer from MikroTik support (in Ticket#2019010222000454):

> This is how scripting works in RouterOS and we will not fix it.

To get around this we use variable names in CamelCase. Let's hope
Mikrotik never ever introduces property names in CamelCase...

*fingers crossed*

1 files changed, 13 insertions, 13 deletions

diff --git a/update-tunnelbroker b/update-tunnelbroker
index fccd41c..cf8af45 100644
--- a/update-tunnelbroker
+++ b/update-tunnelbroker
@@ -3,11 +3,11 @@
 # Copyright (c) 2013-2019 Christian Hesse <mail@eworm.de>
 #                         Michael Gisbers <michael@gisbers.de>
 
-:global tunnelurl;
-:global tunneluser;
-:global tunnelpass;
-:global tunnelid;
-:global tunnelint;
+:global TunnelUrl;
+:global TunnelUser;
+:global TunnelPass;
+:global TunnelId;
+:global TunnelInt;
 
 :global CertificateAvailable;
 
@@ -16,22 +16,22 @@
 }
 
 # get the last ip address from tunnel interface
-:local tunnellastip [ / interface 6to4 get [ / interface 6to4 find where name=$tunnelint ] local-address ];
+:local TunnelLastIp [ / interface 6to4 get [ / interface 6to4 find where name=$TunnelInt ] local-address ];
 
 # Get the current ip address from cloud
 / ip cloud force-update;
-while ([ / ip cloud get status ] != "updated" ) do={
+:while ([ / ip cloud get status ] != "updated") do={
   :delay 1s;
 }
-:local tunnelip [ / ip cloud get public-address ];
+:local TunnelIp [ / ip cloud get public-address ];
 
-:if ($tunnelip != $tunnellastip) do={
+:if ($TunnelIp != $TunnelLastIp) do={
   $CertificateAvailable "Starfield Secure Certificate Authority - G2" "starfield";
-  :log info ("Local address changed, sending UPDATE to tunnelbroker! New address: " . $tunnelip);
+  :log info ("Local address changed, sending UPDATE to tunnelbroker! New address: " . $TunnelIp);
   / tool fetch mode=https check-certificate=yes-without-crl \
-      ("https://" . $tunnelurl . "/nic/update\?hostname=" . $tunnelid) \
-      user=$tunneluser password=$tunnelpass keep-result=no;
-  / interface 6to4 set [ / interface 6to4 find where name=$tunnelint ] local-address=$tunnelip;
+      ("https://" . $TunnelUrl . "/nic/update\?hostname=" . $TunnelId) \
+      user=$TunnelUser password=$TunnelPass keep-result=no;
+  / interface 6to4 set [ / interface 6to4 find where name=$TunnelInt ] local-address=$TunnelIp;
 } else={
   :log debug "All tunnelbroker configuration is up to date.";
 }