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README.md

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@ -21,45 +21,58 @@ If you're a bash expert, you probably don't need this. But for those of us who
can use a bit of Clojure in their shell scripts, it may be useful. can use a bit of Clojure in their shell scripts, it may be useful.
Babashka runs as a [GraalVM](https://github.com/oracle/graal) binary which Babashka runs as a [GraalVM](https://github.com/oracle/graal) binary which
results in fast startup times: results in faster startup time than Clojure on the JVM.
``` shellsession The sweet spot for babashka is executing short Clojure snippets in the same
$ time clojure -e "(+ 1 2 3)" space where you would use bash.
6
clojure -e "(+ 1 2 3)" 3.29s user 0.32s system 99% cpu 3.638 total
$ time planck -e '(+ 1 2 3)'
6
plk -e '(+ 1 2 3)' 1.34s user 0.16s system 127% cpu 1.172 total
$ time bb '(+ 1 2 3)'
6
bb '(+ 1 2 3)' 0.01s user 0.01s system 37% cpu 0.046 total
```
It uses [sci](https://github.com/borkdude/sci) for interpreting Clojure. A
trade-off is that [sci](https://github.com/borkdude/sci) implements only a
subset of Clojure. Also, execution time may be slower than Clojure on the JVM or
(self-hosted) ClojureScript for more CPU-intensive calculations like:
``` shellsession
(last (take 1000000 (repeatedly #(+ 1 2 3))))
```
This would take 5 seconds using babashka, around half a second using self-hosted
ClojureScript and around 200ms in Clojure on the JVM.
So the sweet spot for babashka is executing tasks from the command line where
fast startup time is preferred, in the same space where you would use bash.
Where it can, babashka calls the regular implementation of Clojure on the JVM Where it can, babashka calls the regular implementation of Clojure on the JVM
and proxies common Java packages like `System` and `File`, so writing code in it and proxies common Java packages like `System` and `File`, so writing code in it
should be familiar if you're already using Clojure on the JVM. should be familiar if you're already using Clojure on the JVM.
Reasons why babashka may not be the right fit for your use case:
- It uses [sci](https://github.com/borkdude/sci) for interpreting Clojure. Sci
implements only a subset of Clojure.
- Execution time of longer running programs may be slower.
- External libraries are not available (although you may use `load-file` for
loading external scripts).
## Status ## Status
Experimental. Breaking changes are expected to happen at this phase. Experimental. Breaking changes are expected to happen at this phase.
## Examples
``` shellsession
$ ls | bb -i '*in*'
["LICENSE" "README.md" "bb" "doc" "pom.xml" "project.clj" "reflection.json" "resources" "script" "src" "target" "test"]
$ ls | bb -i '(count *in*)'
12
$ bb '(vec (dedupe *in*))' <<< '[1 1 1 1 2]'
[1 2]
$ bb '(filterv :foo *in*)' <<< '[{:foo 1} {:bar 2}]'
[{:foo 1}]
$ bb '(#(+ %1 %2 %3) 1 2 *in*)' <<< 3
6
$ ls | bb -i '(filterv #(re-find #"reflection" %) *in*)'
["reflection.json"]
$ bb '(run! #(shell/sh "touch" (str "/tmp/test/" %)) (range 100))'
$ ls /tmp/test | bb -i '*in*'
["0" "1" "10" "11" "12" "13" "14" "15" "16" "17" "18" "19" "2" "20" "21" ...]
$ bb -O '(repeat "dude")' | bb --stream '(str *in* "rino")' | bb -I '(take 3 *in*)'
("duderino" "duderino" "duderino")
```
More examples can be found in the [gallery](#gallery).
## Installation ## Installation
### Brew ### Brew
@ -119,9 +132,9 @@ Everything after that is bound to *command-line-args*.
The `clojure.core` functions are accessible without a namespace alias. The `clojure.core` functions are accessible without a namespace alias.
The following namespaces are required by default and only available The following namespaces are required by default and available through the
through the aliases. If not all vars are available, they are enumerated pre-defined aliases. You may use `require` + `:as` and/or `:refer` on these
explicitly. namespaces. If not all vars are available, they are enumerated explicitly.
- `clojure.string` aliased as `str` - `clojure.string` aliased as `str`
- `clojure.set` aliased as `set` - `clojure.set` aliased as `set`
@ -182,37 +195,6 @@ $ bb '((fn [x] (println x) (when (not (sig/pipe-signal-received?)) (recur (inc x
2 2
``` ```
## Examples
``` shellsession
$ ls | bb -i '*in*'
["LICENSE" "README.md" "bb" "doc" "pom.xml" "project.clj" "reflection.json" "resources" "script" "src" "target" "test"]
$ ls | bb -i '(count *in*)'
12
$ bb '(vec (dedupe *in*))' <<< '[1 1 1 1 2]'
[1 2]
$ bb '(filterv :foo *in*)' <<< '[{:foo 1} {:bar 2}]'
[{:foo 1}]
$ bb '(#(+ %1 %2 %3) 1 2 *in*)' <<< 3
6
$ ls | bb -i '(filterv #(re-find #"reflection" %) *in*)'
["reflection.json"]
$ bb '(run! #(shell/sh "touch" (str "/tmp/test/" %)) (range 100))'
$ ls /tmp/test | bb -i '*in*'
["0" "1" "10" "11" "12" "13" "14" "15" "16" "17" "18" "19" "2" "20" "21" ...]
$ bb -O '(repeat "dude")' | bb --stream '(str *in* "rino")' | bb -I '(take 3 *in*)'
("duderino" "duderino" "duderino")
```
More examples can be found in the [gallery](#gallery).
## Running a file ## Running a file
Scripts may be executed from a file using `-f` or `--file`: Scripts may be executed from a file using `-f` or `--file`: