A versatile command line tool to deal with streams, with a ("point-free") functional approach.

The project has be brought to a "usable" (~hackable) point. However it is unfinished, notably:

• tests are coming slowly
• infrastructure for tuples and pattern lists is in place, but incomplete
• same goes for affixing types with * (marks unbounded)
• (.. because of the previous one, literal lists are broken and crash type-checking)
• not every function that I would want are implemented, plan is to add as the need comes
• LLVM-based codegen is still far

Similarly to commands such as awk or sed, sel takes a script to apply to its standard input to produce its standard output.

In its most basic form, the script given to sel is a serie of functions separated by , (comma). See the complete syntax. Each function transforms its input and passes its output to the next one:

$ printf 12-42-27 | sel split :-:, map [add 1], join :-:, ln
13-43-28
$ printf abc | sel codepoints, map ln
97
98
99

Help on individual functions can be obtained with -l:

$ sel -l map add
map :: (a -> b) -> [a] -> [b]
	make a new list by applying an unary operation to each value from a list

add :: Num -> Num -> Num
	add two numbers

$ sel -l
[... list of every functions ...]

Project uses the meson build system. With ninja:

$ meson setup build/
$ ninja -C build/
...
$ build/sel -h

Temporarly, more on command usage can be found here.

From there, this will install the executable sel and the library libsel.so, as well as shell completion (if it exists -- implemented: bash):

$ ninja -C build/ install

sel: error while loading shared libraries: libsel.so: cannot open shared object file: No such file or directory

Note that on some distribution (eg. Fedora), meson will install libsel.so under /usr/local/lib{,64}. If it is not found at runtime, you may need to add it manually:

# echo /usr/local/lib64 >/etc/ld.so.conf.d/sel.conf
# ldconfig # rebuild cache

To enable coverage:

$ meson configure build -Db_coverage=true
$ pip install gcovr # for example
$ ninja -C build test # needed by meson
$ ninja -C build coverage

The folder s/ contains the following shell scripts:

• s/el: build and exec as the resulting binary
• s/el-db: same idea, but use gdb (and thus cannot read from stdin)
• s/el-min: same as s/el, but with a reduced set of functions (bins_min, in lib/include/sel/builtins.hpp -- it builds way faster, so can be used for testing by adding the needed functions to bins_min)
• s/test: run the tests given, or all the tests by default
• s/cover: generate coverage report (also xdg-opens it)

the GitHub "Need inspiration?" bit was "super-spoon"