XLT IF Statement

[Stewart]

I need the if statement to test on multiple items.  What are the correct characters to use to group the || statement together?  In most cases this is accomplished with parentheses ( if((a==x || a == z) &&  b==z) {} )

IF

(0).MSH(0).#4(0) eq =AHBEC  ||  0(0).MSH(0).#4(0)  eq =IHSUM &&  2(0).1(0).1(0).0(0).OBX(0).#3(0).[0] =THEID

 

Topic

[Keith McLeod]

You may want to consider a table value to a variable and then test the variable.

ABC –> SEND

DEF –> SEND

Default –> KILL

Use something like @msh4_test

If @msh4_test eq =SEND

Do something….

[Paul Bishop]

Parenthesis are correct.  For a translate, it would be:

if {($a eq =x || $a eq =y) && $b eq =z} {do something}

In a TCL script, it would be:

if {($a eq “x” || $a eq “y”) && $b eq “z”} {do something}

Paul Bishop
Carle Foundation Hospital
Urbana, IL

[Anonymous]

lots of ways to accomplish this, but to use the xlt IF statement, try this:

( 0(0).MSH(0).#4(0) eq =AHBEC || 0(0).MSH(0).#4(0) eq =IHSUM ) && ( 2(0).1(0).1(0).0(0).OBX(0).#3(0).[0] =THEID )

(The second set of parens is optional.)

[Stewart]

I couldn’t get any of these to work correctly.  I broke it down into 2 separate if statements.

[Anonymous]

fyi, I think you were missing the leading “0” in your original post:

0(0).MSH(0).#4(0)

[Vince Angulo]

I’m pretty sure I always end up nesting the AND clause under the OR condition.

In Welch’s Tcl manual there are two full pages on grouping.  Normally, programming 101 says AND precedes OR, but precedence is over-ridden by parens () — however I’ve found that’s not always the case in Tcl (or how it’s implemented in Cloverleaf).

Glad you got it working even if it wasn’t as elegant as you would’ve liked.

[Charlie Bursell]

“however I’ve found that’s not always the case in Tcl (or how it’s implemented in Cloverleaf).”

Can you be more specific?  Tcl as implemented in Cloverleaf uses the same precedence rules as Tcl anywhere.  Also, to the best of my knowledge Tcl uses the same precedence rules as most languages.  I cannot think of one that is different.

https://www.tutorialspoint.com/tcl-tk/tcl_operators_precedence.htm

Operator precedence determines the grouping of terms in an expression. This affects how an expression is evaluated. Certain operators have higher precedence than others; for example, the multiplication operator has higher precedence than the addition operator.

<b>For example</b> : x = 7 + 3 * 2; here, x is assigned 13, not 20 because operator * has higher precedence than +, so it first gets multiplied with 3 * 2 and then adds into 7.

Here, operators with the highest precedence appear at the top of the table, those with the lowest appear at the bottom. Within an expression, higher precedence operators will be evaluated first.

Category	Operator	Associativity
Unary	+ –	Right to left
Multiplicative	* / %	Left to right
Additive	+ –	Left to right
Shift	<< >>	Left to right
Relational	< <= > >=	Left to right
Equality	== !=	Left to right
Bitwise AND	&	Left to right
Bitwise XOR	^	Left to right
Bitwise OR	|	Left to right
Logical AND	&&	Left to right
Logical OR	||	Left to right
Ternary	?:	Right to left

Example

Try the following example to understand the operator precedence available in Tcl language −

<i class=”fa-external-link”></i>Live Demo

<pre class=”prettyprint notranslate prettyprinted”>#!/usr/bin/tclsh

set a 20
set b 10
set c 15
set d 5

set e [expr [expr $a + $b] * $c / $d ] ;# ( 30 * 15 ) / 5
puts “Value of (a + b) * c / d is : $e\n”

set e [expr [expr [expr $a + $b] * $c] / $d] ;# (30 * 15 ) / 5]
puts “Value of ((a + b) * c) / d is : $e\n”

set e [expr [expr $a + $b] * [expr $c / $d] ] ;# (30) * (15/5)
puts “Value of (a + b) * (c / d) is : $e\n”

set e [expr $a + [expr $b * $c ] / $d ] ;# 20 + (150/5)
puts “Value of a + (b * c) / d is : $e\n”</pre>
When you compile and execute the above program, it produces the following result −
<pre class=”result notranslate”>Value of (a + b) * c / d is : 90

Value of ((a + b) * c) / d is : 90

Value of (a + b) * (c / d) is : 90

Value of a + (b * c) / d is : 50</pre>

[Vince Angulo]

Thanks Charlie – I have to agree with everything in your post as it applies to arithmetic operators.  My challenge had been, like Stewart’s original post, with logical operators in an IF statement.  I’ve gotten in the habit of separating the ANDs and ORs into separate IFs, that I don’t have a recent example.  Of course, could’ve been my inexperience with the translate tool as well…

• This reply was modified 4 years, 6 months ago by Vince Angulo.

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