Programmer Guide/Command Reference/FOR: Difference between revisions
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{{DISPLAYTITLE:{{SUBPAGENAME}}}} | {{DISPLAYTITLE:{{SUBPAGENAME}}}} | ||
The <code>FOR</code> executes the commands in the block enclosed by the <code>FOR</code> statement and the corresponding <code>END</code> as long as the (slightly misleadingly named) <code>TO</code> condition holds true. | The <code>FOR</code> loop executes the commands in the block enclosed by the <code>FOR</code> statement and the corresponding <code>END</code> as long as the (slightly misleadingly named) <code>TO</code> condition holds true. | ||
FOR [ <var>target</var> := <var>init</var> ] TO <var> | FOR [ <var>target</var> := <var>init</var> ] TO [[Programmer_Guide/Concepts/Conditional_Expressions|<var>condition</var>]] STEP <var>step</var> | ||
// commands | // commands | ||
// | // … | ||
END | END | ||
;<var>target</var> | ;<var>target</var> | ||
:The incremental counter variable to initialize with the value <var>init</var> (e.g. #i). | :The incremental counter variable to initialize with the value <var>init</var> (e.g. <var>#i</var>). | ||
;<var>init</var> | ;<var>init</var> | ||
:The value with which to initialize the counter variable <var>target</var> (e.g. 0). | :The value with which to initialize the counter variable <var>target</var> (e.g. 0). | ||
;<var> | ;<var>condition</var> | ||
:The condition which should be tested at the start of each loop (e.g. $#i < 10). See | :The condition which should be tested at the start of each loop (e.g. <code>$#i < 10</code>). See [[Programmer_Guide/Concepts/Conditional_Expressions|Conditional Expressions]] for further information on conditional expressions. | ||
;<var>step</var> | ;<var>step</var> | ||
:The | :The (slightly misleadingly named) <code>step</code> clause is an {{STX}} statement for incrementing the counter variable <var>target</var> at the end of each loop, e.g. the statement <code>#i := int $#i+1</code>. | ||
FOR #i := 0 TO $#i < 10 STEP #i := int $#i+1 | FOR #i := 0 TO $#i < 10 STEP #i := int $#i+1 | ||
BUTIL MSGBOX MSG; #i | BUTIL MSGBOX MSG; Variable #i currently is $#i | ||
END | END | ||
// an example without initialisation | // an example without initialisation | ||
FOR TO $#x > $#y STEP #i := int $#i + 1 | FOR TO $#x > $#y STEP #i := int $#i + 1 | ||
// do something here | // do something here … | ||
END | END | ||
Neither of <var>target</var>, <var>init</var>, <var>condition</var> and <var>step</var> should ever contain one of the strings "<code>FOR</code>", "<code>TO</code>" or "<code>STEP</code>". If it does, the {{STx}} will most likely mistake the line for an ill-formed <code>FOR</code> statement. | |||
Latest revision as of 08:39, 1 June 2015
The FOR loop executes the commands in the block enclosed by the FOR statement and the corresponding END as long as the (slightly misleadingly named) TO condition holds true.
FOR [ target := init ] TO condition STEP step // commands // … END
- target
- The incremental counter variable to initialize with the value init (e.g. #i).
- init
- The value with which to initialize the counter variable target (e.g. 0).
- condition
- The condition which should be tested at the start of each loop (e.g.
$#i < 10). See Conditional Expressions for further information on conditional expressions.
- step
- The (slightly misleadingly named)
stepclause is an STx statement for incrementing the counter variable target at the end of each loop, e.g. the statement#i := int $#i+1.
FOR #i := 0 TO $#i < 10 STEP #i := int $#i+1
BUTIL MSGBOX MSG; Variable #i currently is $#i
END
// an example without initialisation FOR TO $#x > $#y STEP #i := int $#i + 1 // do something here … END
Neither of target, init, condition and step should ever contain one of the strings "FOR", "TO" or "STEP". If it does, the STx will most likely mistake the line for an ill-formed FOR statement.
