./make.elv hello
[hhanche(telegram)] You can't do it that way, because elvish does not (currently at least) give you first class access to the top level namespace. But here is one possible solution:
!/usr/bin/env elvish
fun = [&]
fn fun [key val]{ fun[$key] = $val }
fun hello {
echo hello
}
echo running function $args[0]
$fun[$args[0]]
(I forgot to add that word at the end of the above)
[chengxuncc(telegram)] It work like a magic, thank you very much. (re @hhanche: You can't do it that way, because elvish does not (currently at least) give you first class access to the top level namespace. But here is one possible solution:
!/usr/bin/env elvish
fun = [&]
fn fun [key val]{ fun[$key] = $val }
fun hello {
echo hello
}
echo running function $args[0]
$fun[$args[0]])
Yes, @xiaq, I have experience with Clojure and a little bit of Haskell (more reading than writing), as well as the Common Lisp SERIES library. The various stream and channel abstractions in Java come to mind too.
When I saw that Elvish has a constantly function, I assumed—wrongly—that it must have lazily evaluated sequences. Reading the documentation again today, though, I realized that it's a function, but not necessarily a stream generator.
By the way, Common Lisp had constantly before Clojure.
I was trying to write a filter function. Here is my current attempt:
fn filter [pred @rest]{
each [e]{
if ($pred $e) {
put $e
}
}
}However, when I call it like this, it fails:
put 0 1 2 3 | filter [e]{ put ($e > 1) }The error is:
Exception: bad value: command must be callable or string containing relative path, but is string
put (> $e 1) works as intended—so far.
I wrote my first "real" program in Elvish, which mostly involves generating a few maps, serializing them as JSON, and feeding that JSON into an external program.
A few things I missed:
- A command-line flag binding and parsing library
(I didn't stop to try to build one) - Clearer understanding of when parentheses are required around an expression
- Clearer understanding of when to use piped values versus collecting them into an array and passing that as an argument
2 replies
when you have the data that can be processed continuously, you probably should pipe it
> cd website
> make clean
> makefile:// URL or copy it to your web server (e.g., cp -pr . ~/www/elvish).
