I've been working on streaming and pipeline interruption lately. It was
bothering me that checking ctrl+c (something we want to do often) always
requires a bunch of boilerplate like:
```rust
use std::sync::atomic::Ordering;
if let Some(ctrlc) = &engine_state.ctrlc {
if ctrlc.load(Ordering::SeqCst) {
...
```
I added a helper method to cut that down to:
```rust
if nu_utils::ctrl_c::was_pressed(&engine_state.ctrlc) {
...
```
This change makes SQLite queries (`open foo.db`, `open foo.db | query db
"select ..."`) cancellable using `ctrl+c`. Previously they were not
cancellable, which made it unpleasant to accidentally open a very large
database or run an unexpectedly slow query!
UX-wise there's not too much to show:
## Notes
I was hoping to make SQLite queries streamable as part of this work, but
I ran into 2 problems:
1. `rusqlite` lifetimes are nightmarishly complex and they make it hard
to create a `ListStream` iterator
2. The functions on Nu's `CustomValue` trait return `Value` not
`PipelineData` and so `CustomValue` implementations can't stream data
AFAICT.
This PR changes the `schema` command for viewing the schema of a SQLite
database file. It removes 1 level of nesting (intended to handle
multiple databases in the same connection) that I believe is
unnecessary.
### Before
### After
## Rationale
A SQLite database connection can technically be associated with multiple
non-temporary databases using [the ATTACH DATABASE
command](https://www.sqlite.org/lang_attach.html). But it's not possible
to do that _in the context of Nushell_, and so I believe that there is
no benefit to displaying the schema as if there could be multiple
databases.
I initially raised this concern back in April, but we decided to keep
the database nesting because at the time we were still looking into more
generalized database functionality (i.e. not just SQLite). I believe
that rationale no longer applies.
Also, the existing code would not have worked correctly even if a
connection had multiple databases; for every database, it was looking up
tables without filtering them by database:
6295b20545/crates/nu-command/src/database/values/sqlite.rs (L104-L118)
## Future Work
I'd like to add information on views+triggers to the `schema` output.
I'm also working on making it possible to `ctrl+c` reading from a
database (which is turning into a massive yak shave).
* Apply clippy fix to avoid extra allocation
error: `format!(..)` appended to existing `String`
--> crates/nu-engine/src/documentation.rs:82:9
|
82 | long_desc.push_str(&format!("\n{G}Subcommands{RESET}:\n"));
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: `-D clippy::format-push-string` implied by `-D warnings`
= help: consider using `write!` to avoid the extra allocation
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#format_push_string
error: `format!(..)` appended to existing `String`
--> crates/nu-engine/src/documentation.rs:96:9
|
96 | long_desc.push_str(&format!("\n{G}Parameters{RESET}:\n"));
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= help: consider using `write!` to avoid the extra allocation
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#format_push_string
error: `format!(..)` appended to existing `String`
--> crates/nu-engine/src/documentation.rs:128:9
|
128 | long_desc.push_str(&format!("\n{}Examples{}:", G, RESET));
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= help: consider using `write!` to avoid the extra allocation
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#format_push_string
error: `format!(..)` appended to existing `String`
--> crates/nu-engine/src/documentation.rs:202:5
|
202 | long_desc.push_str(&format!("\n{}Flags{}:\n", G, RESET));
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= help: consider using `write!` to avoid the extra allocation
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#format_push_string
error: could not compile `nu-engine` due to 4 previous errors
* Apply clippy fix to avoid deref on an immutable reference
error: deref on an immutable reference
--> crates/nu-command/src/dataframe/eager/sql_context.rs:188:77
|
188 | SetExpr::Select(select_stmt) => self.execute_select(&*select_stmt)?,
| ^^^^^^^^^^^^^
|
= note: `-D clippy::borrow-deref-ref` implied by `-D warnings`
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#borrow_deref_ref
help: if you would like to reborrow, try removing `&*`
|
188 | SetExpr::Select(select_stmt) => self.execute_select(select_stmt)?,
| ~~~~~~~~~~~
help: if you would like to deref, try using `&**`
|
188 | SetExpr::Select(select_stmt) => self.execute_select(&**select_stmt)?,
| ~~~~~~~~~~~~~~
error: deref on an immutable reference
--> crates/nu-command/src/database/values/dsl/expression.rs:252:15
|
252 | match &*expr {
| ^^^^^^ help: if you would like to reborrow, try removing `&*`: `expr`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#borrow_deref_ref
error: could not compile `nu-command` due to 2 previous errors
* attempts to add `div` math operator
* allows `//` to be used too
* fmt:
* clippy issue
* returns appropriate type
* returns appropriate type 2
* fmt
* ensure consistency; rename to `fdiv`
* Update parser.rs
* dabase access commands
* select expression
* select using expressions
* cargo fmt
* alias for database
* database where command
* expression operations
* and and or operators
* limit and sort by commands
* database commands
* db commands
* filesystem opens sqlite file
* clippy error
* corrected error in ci file
* removes matrix flag from ci
* flax matrix for clippy
* add conditional compile for tests
* add conditional compile for tests
* correct order of command
* correct error msg
* correct typo
