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<H2><A NAME="SECTION00668000000000000000"> </A><A NAME="2381"> </A>
<BR>
Entry points
</H2>
<P>
It is sometimes desirable to group several related procedures into a single
file. In MIDAS, the <TT>ENTRY</TT> command defines entry points for different
procedures in the same file. These individual procedures are executed by
specifying also their entry point besides the file name in the <TT>`@@'</TT>
command.
<P>
<BLOCKQUOTE>
<TT>!+ <BR>
! Example 18, MIDAS procedure exa18.prg <BR>
!+ <BR>
DEFINE/PARAM P1 11 NUMBER "Enter input number: " <BR>
DEFINE/MAXPAR 1 </TT>! only one parameter expected<TT>
<BR>
WRITE/OUT "Parameter 1 = </TT><IMG
WIDTH="17" HEIGHT="44" ALIGN="MIDDLE" BORDER="0"
SRC="img178.gif"
ALT="$\{$"><TT>P1</TT><IMG
WIDTH="16" HEIGHT="44" ALIGN="MIDDLE" BORDER="0"
SRC="img179.gif"
ALT="$\}$"><TT>" <BR>
! <BR>
ENTRY 2 <BR>
DEFINE/PARAM P1 new C "Enter input: " <BR>
DEFINE/MAXPAR 1 </TT>! only one parameter expected<TT>
<BR>
WRITE/OUT "Parameter 1 = </TT><IMG
WIDTH="17" HEIGHT="44" ALIGN="MIDDLE" BORDER="0"
SRC="img180.gif"
ALT="$\{$"><TT>P1</TT><IMG
WIDTH="16" HEIGHT="44" ALIGN="MIDDLE" BORDER="0"
SRC="img181.gif"
ALT="$\}$"><TT>" <BR>
! <BR>
ENTRY third <BR>
DEFINE/PARAM P1 spiral IMA "Enter input image: " <BR>
DEFINE/MAXPAR 1 </TT>! only one parameter expected<TT>
<BR>
WRITE/OUT "Parameter 1 = </TT><IMG
WIDTH="17" HEIGHT="44" ALIGN="MIDDLE" BORDER="0"
SRC="img182.gif"
ALT="$\{$"><TT>P1</TT><IMG
WIDTH="16" HEIGHT="44" ALIGN="MIDDLE" BORDER="0"
SRC="img183.gif"
ALT="$\}$"><TT>" <BR></TT></BLOCKQUOTE> <BR>
The string following the <TT>ENTRY</TT> command (max. 8 characters) is used in
the <TT>`@@'</TT> command to select the code segment in the file <TT>exa18.prg</TT>.
Thus, <TT>@@ exa18,2 old</TT> will result in the display of the line:
<TT>`Parameter 1 = old'</TT>; the following <TT>ENTRY</TT> statements indicates the
end of this code segment and acts like a <TT>RETURN</TT> statement.
Entering <TT>@@ exa18,third</TT> produces the output:
<TT>`Parameter 1 = spiral'</TT>;
and <TT>@@ exa18 -12</TT> will execute the lines with no preceding
<TT>ENTRY</TT> statement, i.e. write: <TT>`Parameter 1 = -12'</TT>.
This example also shows that parameter P1 is not global, that means it has to
be defined in each <TT>ENTRY</TT> segment of the procedure file.
<BR>
Entries may also be used to structure the contents of a MIDAS procedure.
In the following example, the procedure <TT>exa18.prg</TT> executes different
code segments according to its first parameter.
<P>
<BLOCKQUOTE>
<TT>!+ <BR>
! Example 19, MIDAS procedure exa19.prg <BR>
!+ <BR>
DEFINE/PARAM P1 000 C "Enter control flags for entries: " <BR>
DEFINE/PARAM P2 sombrero IMA "Enter image to work with: " <BR>
DEFINE/MAXPAR 2 </TT>! max 2 parameters expected<TT>
<BR>
! <BR>
DEFINE/LOCAL LOOP/I/1/1 0 <BR>
DEFINE/LOCAL CCC/C/1/3 </TT><IMG
WIDTH="17" HEIGHT="44" ALIGN="MIDDLE" BORDER="0"
SRC="img184.gif"
ALT="$\{$"><TT>P1(1:3)</TT><IMG
WIDTH="16" HEIGHT="44" ALIGN="MIDDLE" BORDER="0"
SRC="img185.gif"
ALT="$\}$"><TT> <BR>
SET/FORMAT I1 <BR>
DO LOOP = 1 3 <BR>
IF CCC(</TT><IMG
WIDTH="17" HEIGHT="44" ALIGN="MIDDLE" BORDER="0"
SRC="img186.gif"
ALT="$\{$"><TT>LOOP</TT><IMG
WIDTH="16" HEIGHT="44" ALIGN="MIDDLE" BORDER="0"
SRC="img187.gif"
ALT="$\}$"><TT>:</TT><IMG
WIDTH="17" HEIGHT="44" ALIGN="MIDDLE" BORDER="0"
SRC="img188.gif"
ALT="$\{$"><TT>LOOP</TT><IMG
WIDTH="16" HEIGHT="44" ALIGN="MIDDLE" BORDER="0"
SRC="img189.gif"
ALT="$\}$"><TT>) .EQ. "1" @@ exa19,000</TT><IMG
WIDTH="17" HEIGHT="44" ALIGN="MIDDLE" BORDER="0"
SRC="img190.gif"
ALT="$\{$"><TT>LOOP</TT><IMG
WIDTH="16" HEIGHT="44" ALIGN="MIDDLE" BORDER="0"
SRC="img191.gif"
ALT="$\}$"><IMG
WIDTH="17" HEIGHT="44" ALIGN="MIDDLE" BORDER="0"
SRC="img192.gif"
ALT="$\{$"><TT>P2</TT><IMG
WIDTH="16" HEIGHT="44" ALIGN="MIDDLE" BORDER="0"
SRC="img193.gif"
ALT="$\}$"><TT> <BR>
ENDDO <BR>
! <BR>
! here the different sub-procedures <BR>
! <BR>
ENTRY 0001 <BR>
! <BR>
CREATE/IMAGE </TT><IMG
WIDTH="17" HEIGHT="44" ALIGN="MIDDLE" BORDER="0"
SRC="img194.gif"
ALT="$\{$"><TT>P1</TT><IMG
WIDTH="16" HEIGHT="44" ALIGN="MIDDLE" BORDER="0"
SRC="img195.gif"
ALT="$\}$"><TT> 2,256,256 ? gauss 128.5,128,128.5,128 <BR>
! <BR>
ENTRY 0002 <BR>
! <BR>
READ/DESCR </TT><IMG
WIDTH="17" HEIGHT="44" ALIGN="MIDDLE" BORDER="0"
SRC="img196.gif"
ALT="$\{$"><TT>P1</TT><IMG
WIDTH="16" HEIGHT="44" ALIGN="MIDDLE" BORDER="0"
SRC="img197.gif"
ALT="$\}$"><TT> <BR>
! <BR>
ENTRY 0003 <BR>
! <BR>
STATIST/IMAGE </TT><IMG
WIDTH="17" HEIGHT="44" ALIGN="MIDDLE" BORDER="0"
SRC="img198.gif"
ALT="$\{$"><TT>P1</TT><IMG
WIDTH="16" HEIGHT="44" ALIGN="MIDDLE" BORDER="0"
SRC="img199.gif"
ALT="$\}$"><TT> <BR></TT></BLOCKQUOTE> <BR>
Then, to read the standard descriptors of image frame <TT>luna.bdf</TT> we would
enter the command <TT>@@ exa19 010 luna</TT>;
to create the frame <TT>sol.bdf</TT> we enter
<TT>@@ exa19 100 sol</TT>. Finally, in order to create a gaussian image
<TT>estrella.spc</TT>, and read its standard descriptors and do the statistics
on the newly created image, we type the command <BR>
<TT>@@ exa19 111 estrella.spc</TT>.
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<ADDRESS>
<I>Petra Nass</I>
<BR><I>1999-06-09</I>
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