On Wed, Mar 10, 2021 at 09:44:15AM -0500, Matthias Felleisen wrote: > > Hi, are you aware of rash? Different goals but perhaps a merger of your > package with rash would give us a heck of a new shell :-)
Hey, I took a look at rash, but racket (with fluent) turned out to be better suited to my needs. I definitely find myself turning to racket more often now for tasks I would have normally done with bash (which was the whole point). Racket startup time is quite a bit slower, but I got over it. Not sure if I'd take on the bold task of releasing a new shell though. > > > > > On Mar 9, 2021, at 10:20 AM, Roger Keays <[email protected]> wrote: > > > > Hi all, > > > > I recently publish a new package called *fluent* which adds some syntax > > enhancements to Racket. Links and README below. Let me know what you > > think... > > > > Roger > > > > https://pkgs.racket-lang.org/package/fluent > > https://github.com/rogerkeays/racket-fluent/ > > > > # fluent > > > > UNIX style pipes and a lambda shorthand syntax to make your Racket code > > more readable. > > > > ## ? Unpopular So LISP Is Why > > > > Let's be honest. LISP missed a huge opportunity to change the world by > > telling developers they have to think backwards. Meanwhile, UNIX became > > successful largely because it allows you to compose programs sequentially > > using pipes. Compare the difference (the LISP example is actually racket): > > > > UNIX: cat data.txt | grep "active" | cut -f 4 | uniq | sort > > LISP: (sort (remove-duplicates (map (λ (line) (list-ref (string-split > > line) 4)) ((filter (λ (line) (string-contains? line "active")) (file->lines > > "data.txt")))))) > > > > Using *fluent*, the same racket code can be written according to the UNIX > > philosophy: > > > > ("data.txt" > file->lines >> filter (line : line > string-contains? > > "active") >> map (line : line > string-split > list-ref 4) > > > remove-duplicates > sort) > > > > You can use unicode → instead of > if you prefer. It is more distinctive > > and a bit easier on the eyes: > > > > ("data.txt" → file->lines →→ filter (line : line → string-contains? > > "active") →→ map (line : line → string-split → list-ref 4) → > > remove-duplicates → sort) > > > > ## Function Composition > > > > Using the function composition operator (> or →), *fluent* inserts the left > > hand side as the first parameter to the procedure on the right hand side. > > Use >> (or →→) to add the left hand side as the last parameter to the > > procedure. > > > > (data > procedure params) becomes (procedure data params) > > (data >> procedure params) becomes (procedure params data) > > > > This operation can be chained or nested as demonstrated in the examples. > > > > ## Lambda Shorthand > > > > The : operator allows you to easily write a lambda function with one > > expression. Parameters go on the left, the expression on the right, no > > parentheses required. For example: > > > >> ((x : + x 1) 1) > > 2 > >> ((x y : + x y) 1 2) > > 3 > >> (map (x : string-upcase x) '("a" "b" "c")) > > '("A" "B" "C") > > > > ## Math Procedures > > > > Since this library uses > for function composition, the built in > > greater-than procedure is renamed to `gt?`. Note, this could break existing > > code if you are already using the > procedure. Other math procedures are > > also renamed for consistency, and because the text versions read more > > naturally when using function composition. > > > >> gt? > > < lt? > >> = gte? > > <= lte? > > + add > > - subtract > > * multiply > > / divide > > > > ## Convenience Procedures > > > > *fluent* works best when the data (input) parameter comes first. Most > > racket functions do this out of the box, but many functions which take a > > procedure as a parameter put the data last. That's fine, because you can > > just use >>. Alternatively you can wrap and rename the procedure, which is > > what we've done for these functions: > > > > original data-first version > > ----------------------------- > > for-each iterate > > > > example: > > > >> ('(1 2 3) → iterate (x : displayln x)) > > 1 > > 2 > > 3 > > > > ## Comparison to Clojure's Threading Macro > > > > Clojure's threading macro is a prefix operator, which means it is less > > readable when nested and requires more parentheses. You could say that the > > *fluent* infix operator acts as one parenthesis. Compare: > > > > CLOJURE (prefix): > > > > (-> (list (-> (-> id3 (hash-ref 'genre "unknown")) normalise-field) > > (-> (-> id3 (hash-ref 'track "0")) normalise-field) > > (-> (-> id3 (hash-ref 'artist "unknown")) normalise-field) > > (-> (-> id3 (hash-ref 'title "unknown")) normalise-field)) > > (string-join ".")) > > > > FLUENT (infix): > > > > (list (id3 → hash-ref 'genre "unknown" → normalise-field) > > (id3 → hash-ref 'track "0" → normalise-field) > > (id3 → hash-ref 'artist "unknown" → normalise-field) > > (id3 → hash-ref 'title "unknown" → normalise-field)) → string-join > > ".") > > > > Fluent's infix approach also makes it easier to combine thread-first (→) > > with thread-last (→→). > > > > ## How to enter → with your keyboard > > > > → is Unicode character 2192. On linux you can enter this using > > `shift-ctrl-u 2192 enter`. Naturally, if you want to use this character, > > you should map it to some unused key on your keyboard. This can be done > > with xmodmap: > > > > # use xev to get the keycode > > $ xev > > > > # check the current mapping > > $ xmodmap -pke > > > > # replace the mapping > > $ xmodmap -e "keycode 51=U2192 Ccedilla ccedilla Ccedilla braceright > > breve braceright" > > > > Making this change permanent depends on your session manager. Search > > duckduckgo for details. > > > > ## Installation > > > > This library is available from the Racket package collection and can be > > installed with raco: > > > > $ raco pkg install fluent > > > > All you need to do is `(require fluent)`. You can try it out in the REPL: > > > >> (require fluent) > >> ("FOO" > string-downcase) > > "foo" > >> ((x y : x > add y) 1 2) > > 3 > > > > -- > > You received this message because you are subscribed to the Google Groups > > "Racket Users" group. > > To unsubscribe from this group and stop receiving emails from it, send an > > email to [email protected]. > > To view this discussion on the web visit > > https://groups.google.com/d/msgid/racket-users/sigid.1702887e81.20210309152029.GA3105%40papaya.papaya. > -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/racket-users/sigid.070424dcf4.20210311162023.GA7111%40papaya.papaya.
