$NetBSD: README,v 1.2 2006/02/15 18:12:37 rillig Exp $
== Current problems ==
The current pkglint architecture will not scale much further. What is
needed next are parsers for nested, non-context-free languages (make(1),
sh(1), sed(1)). The parsers should be able to recognize partial
structures, as well as structures containing foreign parts. This is
because most of pkgsrc is heavily based on preprocessors:
- The .if and .for directives in Makefiles are preprocessed by make(1)
before building dependencies and shell commands out of the remaining
text.
- make(1) assembles shell commands from literal text and variables like
${PKGNAME}.
- Shell commands often use dynamic evaluation of variables.
All this makes enhancing pkglint non-trivial. If you know of any
academic papers that might be of help in this case, please tell me.
Additionally, the Perl programming language is not well suited to this
kind of tool. It does not provide:
- Sufficient static checking (especially for names of methods)
- A type system (you can apply almost any operator to any kind of data)
- Object orientation (needed for the future advanced parsers)
- Narrow scope for constants (it's just ugly)
- Enumeration data types
- Structured data types
The pkglint source code is much too big for a single file.
== The pkglint type system ==
The framework for defining data types in the makevars.map file is
insufficient. It does not allow ACLs that specify which variables may
be read or written by the various actors in pkgsrc. At the moment, the
data type and the permissions are intermixed (see type Readonly).
Actors:
package -> the package author
system -> the pkgsrc infrastructure
include -> included make files
bl3 -> buildlink3 files
user -> the user via mk.conf
cmdline -> the user via the command line
Actions:
default -> provide a default value for a variable
append -> append to a list
write -> create or overwrite a variable
readpp -> read the value of a variable during preprocessing
read -> read the value of a variable during execution of the
shell commands
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