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8da27a1a09
# Description
This PR creates a new `Record` type to reduce duplicate code and
possibly bugs as well. (This is an edited version of #9648.)
- `Record` implements `FromIterator` and `IntoIterator` and so can be
iterated over or collected into. For example, this helps with
conversions to and from (hash)maps. (Also, no more
`cols.iter().zip(vals)`!)
- `Record` has a `push(col, val)` function to help insure that the
number of columns is equal to the number of values. I caught a few
potential bugs thanks to this (e.g. in the `ls` command).
- Finally, this PR also adds a `record!` macro that helps simplify
record creation. It is used like so:
```rust
record! {
"key1" => some_value,
"key2" => Value::string("text", span),
"key3" => Value::int(optional_int.unwrap_or(0), span),
"key4" => Value::bool(config.setting, span),
}
```
Since macros hinder formatting, etc., the right hand side values should
be relatively short and sweet like the examples above.
Where possible, prefer `record!` or `.collect()` on an iterator instead
of multiple `Record::push`s, since the first two automatically set the
record capacity and do less work overall.
# User-Facing Changes
Besides the changes in `nu-protocol` the only other breaking changes are
to `nu-table::{ExpandedTable::build_map, JustTable::kv_table}`.
100 lines
2.2 KiB
Rust
100 lines
2.2 KiB
Rust
use crate::Value;
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use serde::{Deserialize, Serialize};
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#[derive(Debug, Clone, Default, Serialize, Deserialize)]
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pub struct Record {
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pub cols: Vec<String>,
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pub vals: Vec<Value>,
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}
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impl Record {
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pub fn new() -> Self {
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Self::default()
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}
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pub fn with_capacity(capacity: usize) -> Self {
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Self {
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cols: Vec::with_capacity(capacity),
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vals: Vec::with_capacity(capacity),
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}
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}
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pub fn iter(&self) -> Iter {
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self.into_iter()
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}
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pub fn iter_mut(&mut self) -> IterMut {
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self.into_iter()
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}
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pub fn is_empty(&self) -> bool {
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self.cols.is_empty() || self.vals.is_empty()
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}
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pub fn len(&self) -> usize {
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usize::min(self.cols.len(), self.vals.len())
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}
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pub fn push(&mut self, col: impl Into<String>, val: Value) {
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self.cols.push(col.into());
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self.vals.push(val);
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}
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}
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impl FromIterator<(String, Value)> for Record {
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fn from_iter<T: IntoIterator<Item = (String, Value)>>(iter: T) -> Self {
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let (cols, vals) = iter.into_iter().unzip();
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Self { cols, vals }
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}
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}
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pub type IntoIter = std::iter::Zip<std::vec::IntoIter<String>, std::vec::IntoIter<Value>>;
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impl IntoIterator for Record {
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type Item = (String, Value);
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type IntoIter = IntoIter;
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fn into_iter(self) -> Self::IntoIter {
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self.cols.into_iter().zip(self.vals)
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}
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}
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pub type Iter<'a> = std::iter::Zip<std::slice::Iter<'a, String>, std::slice::Iter<'a, Value>>;
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impl<'a> IntoIterator for &'a Record {
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type Item = (&'a String, &'a Value);
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type IntoIter = Iter<'a>;
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fn into_iter(self) -> Self::IntoIter {
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self.cols.iter().zip(&self.vals)
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}
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}
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pub type IterMut<'a> = std::iter::Zip<std::slice::Iter<'a, String>, std::slice::IterMut<'a, Value>>;
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impl<'a> IntoIterator for &'a mut Record {
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type Item = (&'a String, &'a mut Value);
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type IntoIter = IterMut<'a>;
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fn into_iter(self) -> Self::IntoIter {
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self.cols.iter().zip(&mut self.vals)
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}
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}
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#[macro_export]
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macro_rules! record {
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{$($col:expr => $val:expr),+ $(,)?} => {
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$crate::Record {
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cols: vec![$($col.into(),)+],
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vals: vec![$($val,)+]
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}
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};
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{} => {
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$crate::Record::new()
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};
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}
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