AutoGen: Comparison

7.2 Competitive Feature Analysis

Here is a feature comparison of AutoOpts and six other command line parser generators. Nearly all of them share these characteristics:

They read a file that describes the program options and produce code to parse command line options. Each has their own format for describing options.
All versions support both short options (flags) and GNU-type long options. clig, however, is unique in that you must choose one or the other. Either way, clig options are introduced with a single hyphen. The other packages identify long options with doubled hyphens.
They produce tailored code for parsing the command line.
They support the C programming language.
The global option state is stored in a global structure.
They produce usage text.

The 7 parsers compared are:

AutoOpts is a component of AutoGen. AutoGen has many capabilities, but here we concentrate on the portion called AutoOpts. AutoOpts is the most general of these programs, and has the most extensive documentation. It is the only one that supports shell and Scheme scripts as well as C programs.
clig can generate either C or Tcl option parsing code. It can also process multiple arguments per single option.
genparse generates a wrapper around getopts_long() to parse the command line options.
gaa supports option input from a configuration file as well as the command line. NOTE HOWEVER: gaa is not maintained.
gengetopt generates a C function that uses getopt_long function to parse the command line options, to validate them and fills a struct.
opt is a subroutine library. Options are specified by calling a registration routine in the library, instead of using a separate option specification file. Global option state is stored in variables passed by address to the registration routine.
wyg uses flex and bison to generate a configuration file parser, but uses getopt_long to parse the command line options.

Comparative Analysis of Differentiating Features
If a feature is present (or absent) in only one or two implementations, then the "yes" or "no" is upper cased for emphasis.

Feature \ Package # 1 2 3 4 5 6 7

shell script app YES no no no no no no

Scheme app YES no no no no no no

Perl app no no no no no YES no

config file input yes no no yes no yes yes

environment input YES no no no no YES no

config file output YES no no no no no no

callback functions yes NO yes yes yes yes NO

multiple occurrence YES YES no no no no no

parameter types [1] 4 5 5 11 [3] 4

enumeration opts YES no no no no no no

optional argument YES YES no no no no no

default values yes yes yes yes NO yes yes

interactive no no no no no YES no

range checks yes yes yes no no no no

consistency checks YES no no no no no no

standard opts YES no no no no no no

man page YES YES no no no no no

texinfo invoking YES no no no no no no

developer dependencies Guile tcl none none none none bison,flex

user dependencies [2] none none none none none none

"multiple occurrence" options may appear multiple times on the command line. Some of the parsers constrain options to appearing once only.

"optional argument" refers to the argument to an option. POSIX and most command line parsers require an option to either not have an argument or else the argument must be supplied on the command line. GNU's getopt_long and some of these parsers support the notion of letting the option argument be "optional".

"consistency checks" verify that conflicting options do not appear together, and options that require other options are allowed only if those other options are present.

"standard options" are pre-defined options that can be trivially incorporated into a user's set of options. They can also thereby be used for standardizing on the flag character and option name.

"interactive" means that the option processing package is able to interactively query the user for option state.

[1] See the list of features, 7.4.2.6 Option Argument Specification.

[2] There is a user-visible dependency iff the developer does a dynamic link to the libopts.so library. Developers are free to either link statically or ship libopts.so with their product. A Debian package would need only a dependency on the package supplying libopts (libopts11, at present). The Guile library is now generally pre-installed on all GNU/Linux systems.

[3] opt supports a different argument type for each fundamental type, plus booleans, inverted booleans, toggling options and a couple others.
-- James R. Van Zandt
-- Bruce Korb

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This document was generated by Bruce Korb on January, 7 2002 using texi2html

Feature \ Package #	1	2	3	4	5	6	7
shell script app	YES	no	no	no	no	no	no
Scheme app	YES	no	no	no	no	no	no
Perl app	no	no	no	no	no	YES	no
config file input	yes	no	no	yes	no	yes	yes
environment input	YES	no	no	no	no	YES	no
config file output	YES	no	no	no	no	no	no
callback functions	yes	NO	yes	yes	yes	yes	NO
multiple occurrence	YES	YES	no	no	no	no	no
parameter types	[1]	4	5	5	11	[3]	4
enumeration opts	YES	no	no	no	no	no	no
optional argument	YES	YES	no	no	no	no	no
default values	yes	yes	yes	yes	NO	yes	yes
interactive	no	no	no	no	no	YES	no
range checks	yes	yes	yes	no	no	no	no
consistency checks	YES	no	no	no	no	no	no
standard opts	YES	no	no	no	no	no	no
man page	YES	YES	no	no	no	no	no
texinfo invoking	YES	no	no	no	no	no	no
developer dependencies	Guile	tcl	none	none	none	none	bison,flex
user dependencies	[2]	none	none	none	none	none	none