Programmer Guide/Command Reference/IF: Difference between revisions
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There are two forms of the <code>IF</code> syntax. The first allows the conditional execution of one command: | There are two forms of the <code>IF</code> syntax. The first allows the conditional execution of one command: | ||
IF <var>condition</var> singlecommand | IF [[Programmer_Guide/Concepts/Conditional_Expressions|<var>condition</var>]] singlecommand | ||
IFNOT <var>condition</var> singlecommand | |||
IFNOT [[Programmer_Guide/Concepts/Conditional_Expressions|<var>condition</var>]] singlecommand | |||
The second allows conditional execution of multiple commands within a block: | The second allows conditional execution of multiple commands within a block: | ||
IF condition THEN | |||
IF <var>[[Programmer_Guide/Concepts/Conditional_Expressions|condition<sub>1</sub>]]</var> THEN | |||
ELSE IF condition THEN | … | ||
ELSE IF <var>[[Programmer_Guide/Concepts/Conditional_Expressions|condition<sub>2</sub>]]</var> THEN | |||
ELSE IFNOT condition THEN | … | ||
ELSE IFNOT <var>[[Programmer_Guide/Concepts/Conditional_Expressions|condition<sub>n</sub>]]</var> THEN | |||
… | |||
ELSE | ELSE | ||
… | |||
END | END | ||
Note that only <code>IF</code> clause mandatory, all other clauses are optional | |||
Note that only the <code>IF</code> clause is mandatory, all other clauses are optional. Empty clauses (i.e., clauses without commands) are allowed. The last clause must be closed with an <code>[[Programmer Guide/Command Reference/END|END]]</code> statement. For more information on conditions see [[Programmer_Guide/Concepts/Conditional_Expressions|Conditional Expressions]]. | |||
Neither the [[Programmer_Guide/Concepts/Conditional_Expressions|<var>condition</var>]] nor the <code>singlecommand</code> should contain the string <code>THEN</code>. If either does, in most cases {{STx}} will amazingly mistake the whole command for an ill-formed <code>IF</code> … <code>THEN</code> … <code>END</code> block. | |||
Latest revision as of 16:42, 25 April 2014
There are two forms of the IF syntax. The first allows the conditional execution of one command:
IF condition singlecommand
IFNOT condition singlecommand
The second allows conditional execution of multiple commands within a block:
IF condition1 THEN … ELSE IF condition2 THEN … ELSE IFNOT conditionn THEN … ELSE … END
Note that only the IF clause is mandatory, all other clauses are optional. Empty clauses (i.e., clauses without commands) are allowed. The last clause must be closed with an END statement. For more information on conditions see Conditional Expressions.
Neither the condition nor the singlecommand should contain the string THEN. If either does, in most cases STx will amazingly mistake the whole command for an ill-formed IF … THEN … END block.
