Concatenate -e flags in CLI before eval #1089
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MRI Ruby's CLI can run multiple `-e` commands even when individual
commands have malformed syntax:
```console
$ ruby -e '2.times {' -e 'puts "foo: #{__LINE__}"' -e '}'
foo: 2
foo: 2
```
Artichoke's CLI currently evals each `-e` command one at a time and
manually increments the parser line number. This same set of commands
fails with a syntax error:
```console
$ cargo -q run --bin artichoke -- -e '2.times {' -e 'puts "foo"' -e '}'
syntax error (SyntaxError)
```
With this patch, Artichoke's Ruby CLI frontend collects all given `-e`
commands into a single `OsString`, separating each command with a
newline. This results in the correct behavior:
```console
$ cargo -q run --bin artichoke -- -e '2.times {' -e 'puts "foo: #{__LINE__}"' -e '}'
foo: 2
foo: 2
```
lopopolo
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JohnTitor
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to JohnTitor/rust
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Mar 14, 2021
…=joshtriplett Implement Extend and FromIterator for OsString Add the following trait impls: - `impl Extend<OsString> for OsString` - `impl<'a> Extend<&'a OsStr> for OsString` - `impl FromIterator<OsString> for OsString` - `impl<'a> FromIterator<&'a OsStr> for OsString` Because `OsString` is a platform string with no particular semantics, concatenating them together seems acceptable. I came across a use case for these trait impls in artichoke/artichoke#1089: Artichoke is a Ruby interpreter. Its CLI accepts multiple `-e` switches for executing inline Ruby code, like: ```console $ cargo -q run --bin artichoke -- -e '2.times {' -e 'puts "foo: #{__LINE__}"' -e '}' foo: 2 foo: 2 ``` I use `clap` for command line argument parsing, which collects these `-e` commands into a `Vec<OsString>`. To pass these commands to the interpreter for `Eval`, I need to join them together. Combining these impls with `Iterator::intersperse` rust-lang#79524 would enable me to build a single bit of Ruby code. Currently, I'm doing something like: ```rust let mut commands = commands.into_iter(); let mut buf = if let Some(command) = commands.next() { command } else { return Ok(Ok(())); }; for command in commands { buf.push("\n"); buf.push(command); } ``` If there's interest, I'd also like to add impls for `Cow<'a, OsStr>`, which would avoid allocating the `"\n"` `OsString` in the concatenate + intersperse use case.
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MRI Ruby's CLI can run multiple
-ecommands even when individual commands have malformed syntax:Artichoke's CLI currently evals each
-ecommand one at a time and manually increments the parser line number. This same set of commands fails with a syntax error:With this patch, Artichoke's Ruby CLI frontend collects all given
-ecommands into a singleOsString, separating each command with a newline. This results in the correct behavior: