1:<rexxtags:page title="Writing a simple calendar tag" type="Tutorial"> 2:<p style="text-align:justify"> Let's try to write a tag which is more complicated
3: (and useful) than in the preceding sections. We will learn of to write a tag
4: which creates calendars. For example, here's a calendar for the current month:</p> 5:<rexxtags:cal1/> 6:<p style="text-align:justify">Here's the code used to create the calendar:<br /> 7: <rexxtags:xmlhighlight lineno="yes"><rexxtags:cal1/></rexxtags:xmlhighlight> 8: <br /> 9: <br /> 10: We'll need to write a <font face="Courier New, Courier, mono">rexxtags.cal1.tag</font> 11: tag procedure (we call it <font face="Courier New, Courier, mono">'cal1'</font> 12: because we'll build more sophisticated versions of this tag later). The tag
13: doesn't need any parameter, and we only need to produce output for the start
14: tag call. The main routine will thus be:
15:<br /> 16:<rexxtags:rexxhighlight lineno="yes"> 17:Parse arg verb
18:
19: If verb = 'START' Then Signal StartTag
20: If verb = 'END' Then Return ''
21:
22:Return 0
23:</rexxtags:rexxhighlight> 24:<br /> 25:<br /> 26:and we'll put all the code in 'StartTag'. If we want our tag to work properly in most versions
27: of Rexx (including old versions of OS/2 Warp 3.0 and 4.0 or WSeB without fixpacks),
28: we can't count on having date arithmetic built-in. We'll use <a href="http://www.rexswain.com/">Rex
29: Swain</a>'s B2MMDDYY and MMDDYY2B and copy them into the code for our tag.</p> 30:<p style="text-align:justify">Next we'll need a routine to calculate what's the
31: weekday for day 1 of a given month:<br /> 32:<rexxtags:rexxhighlight lineno="yes"> 33:DayOfWeekOfDay1: Procedure
34: Parse Arg mm'/'.'/'yy
35:Return (mmddyy2b(mm'/1/'yy) // 7) + 1
36:</rexxtags:rexxhighlight> 37:<br /> 38:<br /> 39:And another one to calculate what's the last day in the month:
40:<br /> 41:<rexxtags:rexxhighlight lineno="yes"> 42:LastDayInMonth: Procedure
43: Parse Arg mm'/'.'/'yy
44: mm = mm + 1
45: If mm > 12 Then Do
46: yy = yy + 1
47: mm = 1
48: End
49: Parse Value b2mmddyy(mmddyy2b(mm'/1/'yy)-1) With '/' lastday '/'
50:Return lastday
51:</rexxtags:rexxhighlight> 52:<br /> 53:<br /> 54: Now the 'StartTag' part is standard REXX. You can find the <a href="/samples/rexxtags.cal1.html">tag
55: code</a> in the <a href="/samples">samples</a> section. </p> 56:</rexxtags:page>
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Last update: 29/12/11 at 14:22
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