Re: Macro Library for Java?

From: (Stefan Ram)
3 Aug 2006 15:53:14 GMT
<> (Stefan Ram) writes:

  Recently, I wrote a GPP macro for a counting loop.

  Java lacks a loop to only express ?repeat the following
  statement n times? and not add any other designation.

  The following prints ?alpha? 6 times.
  Two such loop control macors are nested.

public class Main
{ public static void main ( final java.lang.String[] args )
  { REPEAT( 2 )
    REPEAT( 3 )
    java.lang.System.out.println( "alpha" ); }}

  The code generated is:

public class Main
{ public static void main ( final java.lang.String[] args )
  { for(int SYM1=( 2 );(SYM1--)!=0;)
    for(int SYM2=( 3 );(SYM2--)!=0;)
    java.lang.System.out.println( "alpha" ); }}

  and I did it as follows. gpp does not contain a symbol name
  generator, but is so versatile that one can write it on
  the fly using the powerful ?defeval? and ?eval? meta-macros:

<#define REPEATNAME|0>
<#define NEXTSYM|<#defeval REPEATNAME|<#eval 1+<#REPEATNAME>>>>
<#define REPEAT|<#NEXTSYM>for(int SYM<#REPEATNAME>=(#1);(SYM<#REPEATNAME>--)!=0;)>

  I have defined another gpp-mode, where I can write definitions like:

$define BLOCK new java.lang.Runnable(){ public void run(){$1}}

$define IN_EDT javax.swing.SwingUtilities.invokeLater($1)

  Then, to execute any statement in the EDT:

$define INEDT IN_EDT(BLOCK($1))

  Debug-print where we are:

$define LOCATE do{ java.lang.System.out.print( new java.lang.Throwable().getStackTrace()[0].toString() + ": " ); }while(false)

  Debug-display a reference variable with its name, type and value:

$define DISPLAY do{ LOCATE(); java.lang.System.out.println( "\"$1\" =( " +((( $1 )== null )? "null" :( $1 ).getClass().getName() )+ " )\"" +( $1 )+ "\"." ); }while(false)

  Drawback for the aficionados of Eclipse and similar IDEs:
  The IDE will not recognice some of the macro syntax.

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