C-style MATLAB preprocessor

Simple, only supports ifdef/endif/else with define/undef, simple syntax for &&/||.

Description

Simple, only supports ifdef/endif/else with define/undef and simple syntax for doing boolean expressions.

My apologies to the author of the MPP package (also available). I needed something quick & dirty. Seems to work. Comes with test file.

• MATLAB release: MATLAB 7.6 (R2008a)

[Jan Simon]

I was really happy to see a preprocessor for M-files here, because this could solve a lot of problems.
But after downloading I am disappointed, because there is not documentation in the function!
  function [varargout]=mpp(fn,varargin)
  % Simple MATLAB C-like preprocessor
  % <Author> <Date>
That's all. So I tried to look in the code to get some informations:
Initially the function searchs for something:
  if ~exist([fn,'.m1'])
This could mean a directory, a file name anywhere in the path, a Java class. To check the existence of a file, use EXIST(FileName, 'file') ! This is much faster and less ambiguous.

Then the name of the TEMP folder is obtained:
  tempdir=tempname;
  i=length(tempdir);while tempdir(i)~=filesep&&i>0;i=i-1;end;
  tempdir(i+1:end)=[];
1. "while tempdir(i) ~= filesep && i>0" fails if [i] is 0! Swap the two statements to: "while i> 0 && tempdir(i)~=filesep"
2. Or even better call FILEPARTS:
  tempdir = fileparts(tempname);
3. Or even much better: Do not overwrite Matlab's built-in function with the same name, but use it: TEMPDIR replies the TEMP directory...

I cannot estimate what the complex processing part does. Unfortunately no comments can be found here.

Finally you add the TEMP and its subfolders to the Matlab path "addpath(genpath(tempdir))" without removing it afterwards. This can lead to unwanted side-effects.

As conclusion I confirm the description: "something quick & dirty. Seems to work."
I'd strongly suggest some general improvements: Clean up the code, add much more comments, add a help section which explain inputs, outputs and what happens. Otherwise your program is not useful or usable by members of the FEX.
The idea is really good and MPP Fex: #7150 does not satisfy my needs.

[Siyi Deng]