6 Rules IF ELSE ELSEIF and AND OR Support

blakadder edited this page 2019-11-13 14:46:29 +01:00

Table of Contents

• Major features
• Syntax
• In English
• Example

This feature is not included in precompiled binaries.
To use it you must compile your build. Add the following to user_config_override.h:

#define USE_EXPRESSION         // Add support for expression evaluation in rules (+3k2 code, +64 bytes mem)  
#define SUPPORT_IF_STATEMENT   // Add support for IF statement in rules (+4k2 code, -332 bytes mem)  

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Major features

• Support IF, ELSEIF, ELSE
• Support for <comparison> and <logical expression> as condition
• Support for executing multiple commands
• Support for nested IF statements
• Available free RAM is the only limit for logical operators, parenthesis, and nested IF statements.

Note: All the commands executed within an IF block are performed via Backlog

Syntax

<if-statement>

• IF (<logical-expression>) <statement-list> {ELSEIF (<logical-expression>) <statement-list>} [ELSE <statement-list>] ENDIF

<logical-expression>

• <comparison-expression>
• ( <comparison-expression> | <logical-expression> ) {{AND | OR} <logical-expression>}
• ( <logical-expression> ) {AND | OR} <logical expression>}

<comparison-expression>

• <expression> {= | < | > | | | == | <= | >= | !=} <expression>

<statement-list>

• <statement> {; <statement>}

<statement>

• {<Tasmota-command> | <if-statement>}

In English

IF statement supports 3 formats:

• IF (<condition>) <statement-list> ENDIF
• IF (<condition>) <statement-list> ELSE <statement-list> ENDIF
• IF (<condition>) <statement-list> [ELSEIF (<condition>) <statement-list> ] ELSE <statement-list> ENDIF

<condition> is a logical expression, for example:

• VAR1>=10
• Multiple comparison expressions with logical operator AND or OR between them. AND has higher priority than OR. For example:
  UPTIME>100 AND MEM1==1 OR MEM2==1
  Parenthesis can be used to change the priority of logical expression. For example:
  UPTIME>100 AND (MEM1==1 OR MEM2==1)
• The following variables can be used in <condition>:

  Symbol	Description
  VAR<x>	variable (<x> = 1..MAX_RULE_VARS, e.g., VAR2)
  MEM<x>	persistent variable (<x> = 1..MAX_RULE_MEMS, e.g., MEM3)
  TIME	minutes past midnight
  UPTIME	uptime minutes
  UTCTIME	UTC time, UNIX timestamp, seconds since 01/01/1970
  LOCALTIME	local time, UNIX timestamp
  SUNRISE	current sunrise time (minutes past midnight)
  SUNSET	current sunset time (minutes past midnight)

<statement-list>

• A Tasmota command (e.g.,LedPower on)
• Another IF statement (IF ... ENDIF)
• Multiple Tasmota commands or IF statements separated by ;. For example:
  Power1 off; LedPower on; IF (Mem1==0) Var1 Var1+1; Mem1 1 ENDIF; Delay 10; Power1 on
Backlog is implied and is not required (saves rule set buffer space).

Example

Rule used to control pressure cooker with a Sonoff S31. Once it is finished cooking, shut off the power immediately.

Rule1
 on system#boot do var1 0 endon
 on energy#power>100 do if (var1!=1) ruletimer1 0;var1 1 endif endon
 on tele-energy#power<50 do if (var1==1) var1 2;ruletimer1 600 endif endon
 on rules#timer=1 do backlog var1 0;power off endon  

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