statement

OpenTuring

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statement

Syntax

A statement is one of:

(a)	assignmentStatement		% variableReference := expn
(b)	openStatement		% open* …*
(c)	closeStatement		% close* …*
(d)	putStatement		% put* …*
(e)	getStatement		% get* …*
(f)	readStatement		% read* …*
(g)	writeStatement		% write* …*
(h)	seekStatement		% seek* …*
(i)	tellStatement		% tell* …*
(j)	forStatement		% for … end for
(k)	loopStatement		% loop … end loop
(l)	exit [ when trueFalseExpn ]
(m)	ifStatement		% if … end if
(n)	caseStatement		% case … end case
(o)	assert trueFalseExpn
(p)	begin
		statementsAndDeclarations
	end
(q)	procedureCall		% procedureId [(parameters)]
(r)	return
(s)	result expn
(t)	new [ collectionId , ] pointerVariableReference
(u)	free [ collectionId , ] pointerVariableReference
(v)	tag unionVariableReference , expn
(w)	forkStatement		% fork* …*
(x)	signal variableReference
(y)	wait variableReference [ , expn ]
(z)	pause expn
(aa)	quit [ guiltyParty ] [ : quitReason ]
(bb)	unchecked
(cc)	checked

Description

A statement (or command) causes a particular action, for example, the putStatement:

        put "Hello"

outputs Hello. See the descriptions of the individual statements for explanations of their actions. Each statement can optionally by followed by a semicolon (;).

Example

        width := 24         % Assignment statement
        put "Hello world"   % Put statement
        exit when i = 100       % Exit statement
        assert width < 320  % Assert statement

Details

You can use a result statement only in a function. You can use a return statement only to terminate a procedure or the main program (but not to terminate the initialization of a module). See also result and return.

There are a number of predefined procedures, such as drawline, which are not listed as statements above. These are considered procedure calls, which is one form of statement.

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