Expression editors

<body topmargin=0 leftmargin=0 marginheight=0 marginwidth=0> <table cellpadding=0 cellspacing=0 border=0 height="100%"><tr> <td valign="top" width=155 BGCOLOR="#FFFFFF" TEXT="#080000" bgproperties="fixed" background="1f364643.gif"> <div> <A HREF="index.htm" TARGET="_top" TITLE="GenerExe Home of XPad crosscompiler tool"><U><B><IMG SRC="22b99940.gif" border=0 width="153" height="148" ALT="GenerExe Home Page" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></B></U></A></div> <bR> <DIV ALIGN="LEFT"></DIV> <div> <B> <TABLE BORDER="5" CELLPADDING="1" CELLSPACING="1" WIDTH="102" BORDERCOLORLIGHT="#C0C0C0" BORDERCOLORDARK="#808080" FRAME="BOX" RULES="ALL" ALIGN="BOTTOM" HSPACE="0" VSPACE="0" BGCOLOR=#FFFFCC > <tR> <tD VALIGN=TOP HEIGHT= 16 ><NOBR><div> <B>About XPad</B></div> </NOBR></tD> </tR> <tR> <tD VALIGN=TOP HEIGHT= 145 WIDTH="86"><div> <A HREF="id56.htm" TARGET="_top" TITLE="IDE"><U>IDE</U></A></div> <div> <A HREF="id127.htm" TARGET="_top" TITLE="Hardware Configuration"><U>Hardware Configuration</U></A></div> <div> <A HREF="id59.htm" TARGET="_top" TITLE="STDeditor"><U>STD-editor</U></A></div> <div> <A HREF="id58.htm" TARGET="_top" TITLE="FLOWeditors"><U>FLOW-editors</U></A></div> <div> <B>Expression editors</B></div> </tD> </tR> </TABLE></B></div> <bR> </td> <td valign="top" BGCOLOR="#FFFFFF" TEXT="#080000" bgproperties="fixed" background="1ef64643.gif"> <bR> <div> <TABLE BORDER="2" CELLPADDING="2" CELLSPACING="1" WIDTH="666" BORDERCOLORLIGHT="#C0C0C0" BORDERCOLORDARK="#808080" FRAME="BOX" RULES="ALL" ALIGN="BOTTOM" HSPACE="0" VSPACE="0" BGCOLOR=#FFFF80 > <tR> <tD VALIGN=TOP HEIGHT= 27 ><NOBR> <SCRIPT language=JavaScript src="menusrc.js"></SCRIPT><SCRIPT language=JavaScript src="menudef.js"></SCRIPT> <SCRIPT language=JavaScript>drawToolbar();</SCRIPT> </NOBR></tD> </tR> </TABLE></div> <bR> <DIV ALIGN="LEFT"></DIV> <div> <TABLE BORDER="5" CELLPADDING="1" CELLSPACING="1" WIDTH="618" BORDERCOLORLIGHT="#C0C0C0" BORDERCOLORDARK="#808080" FRAME="BOX" RULES="NONE" ALIGN="BOTTOM" HSPACE="0" VSPACE="0" > <tR> <tD VALIGN=TOP COLSPAN=2 HEIGHT= 38 ><NOBR><div> <B>Remember balancing a checkbook before owning a calculator?</B><FONT SIZE="3" COLOR="#000000" FACE="Arial" > </FONT></div> <bR> </NOBR></tD> </tR> <tR> <tD VALIGN=TOP COLSPAN=2 HEIGHT= 33 WIDTH="600"><div> The reason we learned to jot down calculations that way, was because it is the most natural way for our brain to process information: bit by bit, writing down temporary results for verification...</div> </tD> </tR> <tR> <tD VALIGN=TOP COLSPAN=2 HEIGHT= 173 WIDTH="600"><bR> <div> <I>Expressions or more formally "Dynamic Variables" (variables whose values are calculated  based on the current state and not necessarily stored) are your tools to:</I></div> <div> <I><IMG BORDER="0" SRC="Symb075c00b700c80000ff00.gif" HEIGHT="13" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">detect events</I><FONT SIZE="2" COLOR="#111111" FACE="Arial" ><I> (Is it time to switch State?)</I></FONT></div> <div> <I><IMG BORDER="0" SRC="Symb075c00b700c80000ff00.gif" HEIGHT="13" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">take decisions </I><FONT SIZE="2" COLOR="#111111" FACE="Arial" ><I>(Which block of functions needs to be executed next in my Flow-diagram of this state?)</I></FONT></div> <div> <I><IMG BORDER="0" SRC="Symb075c00b700c80000ff00.gif" HEIGHT="13" WIDTH="24" ALIGN="bottom" HSPACE="0" VSPACE="0">perform math/expressions</I></div> <bR> <div> <I>XPad provides an easy to use intuitive metaphor to specify these!</I></div> <bR> </tD> </tR> <tR> <tD VALIGN=TOP HEIGHT= 268 WIDTH="167"><bR> <bR> <div> On the right you see an expression-editor of XPad showing a simple "Increase" expression. It just adds 1 to the variable "Player" and stores the result in the same variable. The C-equivalent would be "Player = Player + 1;".  However, in a flow you can "parameterize" the expression and substitute any of the variables in here, making it a generic function!</div> </tD> <tD VALIGN=TOP><NOBR><div> <IMG SRC="133a1060.jpg" border=0 width="417" height="262" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></div> </NOBR></tD> </tR> <tR> <tD VALIGN=TOP COLSPAN=2 HEIGHT= 391 WIDTH="600"><bR> <div> Below an example of an expression which defines a common function, that stores a value (Par1) in an indexed variable (Par3) AND then increases the index (Par2) by 1.</div> <bR> <DIV ALIGN="LEFT"></DIV> <div> <IMG SRC="1af9d020.gif" border=0 width="413" height="258" ALIGN="BOTTOM" HSPACE="0" VSPACE="0"></div> <bR> <div> Agreed, it takes more (visual) space than the nested brackets, but it is a lot less painful for the brain and the generated code is just as efficient! Also (!) you can reuse any expression (or formula) by simply substituting different variables from the function-editors!</div> </tD> </tR> </TABLE></div> <bR> <bR> </td> </tr></table></body>