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# 17 Escaping examples

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#### Overview

This page provides examples of using correct escaping when using regular expressions in various contexts.

:::notetip
When using the trigger expression constructor, correct escaping in regular expressions is added automatically.
:::

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#### Examples

**User macro with context**

Regular expression: `\.+\"[a-z]+`<br>
User macro with context: `{$MACRO:regex:"\.+\\"[a-z]+"}`

Notice:

-   backslashes are [not escaped](/manual/config/macros/user_macros_context#important-notes);
-   quotation marks are escaped.
			
**Macro function inside item key parameter**

Regular expression: `.+:(\d+)$`<br>
Item key: `net.tcp.service[tcp,,"{{ITEM.VALUE}.regsub(\".+:(\d+)$\",\1)}"]`

Notice:

-   regular expression inside the `regsub` macro function is double-quoted (because of contains closing parenthesis);
-   quotation marks around the regular expression are escaped (because the whole third item parameter is double-quoted);
-   third item key parameter is double-quoted because it contains a comma.

**LLD macro function**

Regular expression: `\.+\"([a-z]+)`<br>
LLD macro: `{{#MACRO}.iregsub("\.+\\"([a-z]+)", \1)}`

Notice:

-   backslashes are not escaped;
-   quotation marks are escaped.

**LLD macro function inside user macro context**

Regular expression: `\.+\"([a-z]+)`<br>
LLD macro: `{{#MACRO}.iregsub("\.+\\"([a-z]+)", \1)}`<br>
User macro with context: `{$MACRO:"{{#MACRO}.iregsub(\"\.+\\\"([a-z]+)\", \1)}"}`

Notice:

-   backslash escaping for LLD does not change;
-   upon inserting the LLD macro into user macro context, we need to put it into string:
   1.   Quotation marks are added around the macro expression;
   2.   Quotation marks get escaped; in total, 3 new backslashes are introduced.

**String parameter of non-history function** 

String content: `\.+\"[a-z]+`<br>
Expression: `concat("abc", "\\.\\\"[a-z]+")`

Notice:

-   String parameters require escaping both for backslashes and quotation marks.

**String parameter of history function** 

String content: `\.+\"[a-z]+`<br>
Expression: `find(__ITEM_KEY__,,"regexp","\.+\\"[a-z]+")`

Notice:

-   backslashes are not escaped;
-   quotation marks are escaped.

**LLD macro function inside string parameter of non-history function**

Regular expression: `\.+\"([a-z]+)`<br>
LLD macro: `{{#MACRO}.iregsub("\.+\\"([a-z]+)", \1)}`<br>
Expression: `concat("abc, "{{#MACRO}.iregsub(\"\\.+\\\\\"([a-z]+)\", \\1)}")`

Notice:

-   String parameters require escaping both for backslashes and quotation marks;
-   Another layer of escaping is added, because the macro will be resolved only after string is unquoted;

**LLD macro function inside string parameter of history function**

Regular expression: `\.+\"([a-z]+)`<br>
LLD macro: `{{#MACRO}.iregsub("\.+\\"([a-z]+)", \1)}`<br>
Expression: `find(__ITEM_KEY__,,"eq","{{#MACRO}.iregsub(\"\.+\\\"([a-z]+)\", \1)}")`

Notice:

-   backslashes are not escaped;
-   quotation marks are escaped.

**User macro with context inside string parameter of non-history function**

Regular expression: `\.+\"[a-z]+`<br>
User macro with context: `{$MACRO:regex:"\.+\\"[a-z]+"}`<br>
Expression: `concat("abc, "{$MACRO:regex:\"\\.+\\\\\"[a-z]+\"}")`

Notice:

-   Same as in the previous example an additional layer of escaping is needed;
-   Backslashes and quotation marks are escaped only for the top-level escaping (by virtue of it being a string parameter).

**User macro with context inside string parameter of history function**

Regular expression: `\.+\"[a-z]+`<br>
User macro with context: `{$MACRO:regex:"\.+\\"[a-z]+"}`<br>
Expression: `find(__ITEM_KEY__,,"eq","{$MACRO:regex:\"\.+\\\"[a-z]+\"}")`

Notice:

-   backslashes are not escaped;
-   quotation marks are escaped.

**LLD macro function inside user macro context inside non-history function**

Regular expression: `\.+\"([a-z]+)`<br>
LLD macro: `{{#MACRO}.iregsub("\.+\\"([a-z]+)", \1)}`<br>
User macro with context: `{$MACRO:"{{#MACRO}.iregsub(\"\.+\\\"([a-z]+)\", \1)}"}`<br>
Expression: `concat("abc, "{$MACRO:\"{{#MACRO}.iregsub(\\\"\.+\\\\\\\"([a-z])+\\\", \\1)}\"}")`

Notice the three layers of escaping:

   1. For LLD macro function, without escaping of backslashes;
   2. For User macro with context, without escaping of backslashes;
   3. For the string parameter of a function, with escaping of backslashes.

**LLD macro function inside user macro context inside history function**

Regular expression: `\.+\"([a-z])+`<br>
LLD macro: `{{#MACRO}.iregsub("\.+\\"([a-z]+)", \1)}`<br>
User macro with context: `{$MACRO:"{{#MACRO}.iregsub(\"\.+\\\"([a-z]+)\", \1)}"}`<br>
Expression: `find(__ITEM_KEY__,,"eq","{$MACRO:\"{{#MACRO}.iregsub(\\"\.+\\\\"([a-z])+\\", \1)}\"}")`

Notice:

-   backslashes are not escaped;
-   quotation marks are escaped.

**User macro with context just inside string**

Regular expression: `\.+\"[a-z]+`<br>
User macro with context: `{$MACRO:regex:"\.+\\"[a-z]+"}`<br>
Inside string of some expression, for example: `func(arg1, arg2, arg3)="{$MACRO:regex:\"\\.+\\\\\"[a-z]+\"}"`

Notice:

-   Strings also require backslash escaping;
-   Strings also require quotation mark escaping;
-   Again a case with 2 levels of escaping:
	1. Escaping for user macro context without backslash escaping;
	2. Escaping for it being a string with backslash escaping.

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