argen lets you generate argument parsing logic in C from a simple
config. No more having to write that tedious arg-parsing C code!
// this is what the entry point looks like from the above example
int main(int argc, char **argv) {
int block_size;
int fave_number;
int quiet;
char* username;
char* out_file;
char* in_file;
char* *words;
size_t words__size;
parse_args(argc, argv, &block_size, &fave_number, &quiet, &username, &out_file, &in_file, &words, &words__size);
/* call your code here */
return 0;
}argen can easily be installed as a pre-built executable. Download from
the latest compiled binaries
and run ./install.
# install rust via rustup.rs
# clone the source code
$ git clone https://github.com/kynelee/argen.git
$ cd argen
# build
$ cargo build --release
# copy binary
$ cp target/release/argen /usr/local/bin/argenIf you intend on doing development, you will find integration testing with gcc easy and pretty with this line:
cargo run -- examples/example_spec.toml | tee a.c | pygmentize -l c && gcc a.c# write to main.c
$ argen -o main.c spec.toml
# write to stdout
$ argen spec.tomlThe spec.toml file specifies how you want your C code to parse arguments:
# argen spec
# example usages:
# $ ./program --block-size 10 --set-flag file1.txt file2.txt word1 word2
# $ ./program file1.txt
# There are "non_positional" options and "positional" arguments.
# These take some different fields.
# This example is exhaustive in showing all available fields.
# Positional arguments are *ordered*:
# All required positional arguments must precede non-required ones.
# Only the last positional argument can be multiple-valued.
####################
## non-positional ##
####################
[[non_positional]]
c_var = "block_size" # required, variable name in C
c_type = "int" # required, variable type in C (int or char*)
# for int: calls atoi(arg) to turn arg into int
long = "block-size" # required, specifies option name
help_name = "num" # optional, name of the option's arg shown in --help output
help_descr = "Set the block size" # optional, description in the --help output
short = "b" # optional, shortcut for argument name, 1 ASCII character only
aliases = ["size"] # optional, aliases for option
default = "12" # optional, default value for variable
# for int: assigned as literal
# for char*: assigned as quoted literal
#required = false # optional, makes the option mandatory
# if set, cannot also provide default
# (defaults to false)
[[non_positional]]
c_var = "flag_set"
c_type = "int"
long = "set-flag"
help_descr = "Enable something"
flag = true # optional, make the option take no argument
# c_type must be int
# c_var is 1 if flag is set, 0 otherwise
# flags cannot also be required
################
## positional ##
################
[[positional]]
c_var = "input_file" # required, variable name in C
c_type = "char*" # required, variable type in C (int or char*)
# for int: calls atoi(arg) to turn arg into int
required = true # optional, makes the argument mandatory
# if set, cannot also provide default
# (defaults to false)
help_name = "FILE" # required, NOTE: this is required unlike non-positional
# name of the argument shown in --help output
help_descr = "input file" # optional, description in the --help output
[[positional]]
c_var = "output_file"
c_type = "char*"
help_name = "OUT"
help_descr = "file for output"
default = "output.txt" # optional, default value for variable
# for int: assigned as literal
# for char*: assigned as quoted literal
[[positional]]
multi = true # optional, only valid for last positional argument
# we note the different behaviors here
c_var = "words"
c_type = "char*" # with multi, we can only use char*
# words will actually be a char**,
# and another variable words__size is made
help_name = "WORD" # with multi, you should be singular here
help_descr = "word(s) to use"
default = "someword" # with multi, if no values are given and a
# default is specified, words__size will be 1
# and words[0] is the default value
# if no values are given and *no* default is
# specified, words_size will be 0
#required = false # with multi, makes at least one value mandatory
# (still defaults to false)After generating and compiling the C code, you will have fully functional argument parsing.