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Warning: Work in progress! Leave feedback on Zulip or Github if you'd like this doc to be updated.

Oil Word Language Extensions

Inline function Calls

That Return Strings

echo $stringfunc(x, y)

NOTE: "__$stringfunc(x, y)__" doesn't work. Do this instead:

var s = stringfunc(x, y)
echo "__$s__"

That Return Arrays

cc -o foo -- @arrayfunc(x, y)

@array

Conclusion: I think the conservative approach is better.

This is the same discussion as $f(x) vs $(f(x))` on the inline function calls thread.

We only want to interpolate vars and functions. Arbitrary expressions aren't necessary.

In summary:

• echo foo=$x interpolates a variable into a unquoted word
• echo foo=$f(x) interpolates a call returning a string into an unquoted word
• echo "foo=$[x] 1 2 3" interpolates a variable into a double quoted string
• echo "foo=${x} 1 2 3" -- older, same
• echo "foo=$[f(x)] 1 2 3" interpolates a call returning a string into a double quoted string

OK I'm pretty happy with this explanation! Shell is messy but Oil is bringing some order to it :)

And then for completeness we also have:

• echo @x interpolates an array into a command
• echo @f(x) interpolates a function returning an array into a command

Unimplemented

${x|html}

${x %.3f}