ant-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "marvin greenberg" <>
Subject Re: What is a 'declarative' language [ was Re: [VOTE] vote on ge neral direction ...]
Date Tue, 27 Mar 2001 13:28:01 GMT
----- Original Message -----
From: "Marvin Greenberg" <>
To: <>
Sent: Monday, 26 March, 2001 2:39 PM
Subject: Re: [DISC] procedural versus purely declarative

> > * build files should be purely declarative
> Can anyone come up with a definition of "declarative" we can all agree
> on?
> Glenn
How about, the content of the build file should, to the maximum extent
declare only:
   the steps that are part of the build
   the inputs required by each step
   the results from each step
   the constraints upon each step (dependencies and conditions when the step
      is unneeded)

This way the build file talks to the configuration manager or build process

The reason (I believe) things like foreach or looping are bad, is that it
requires thought and interpretation to understand what they actually do.
Yes, we're all  a bunch of programmers, and CM people will probably be
too, but if you look at old makefiles, the amount of "procedural" stuff that
creeps in can make it  very hard to understand what the build is building.
These constructs also make it hard for a system to analyze dependencies
and decide whether something needs to be done (since the Task
becomes opaque to the system.)

View raw message