37 lines
945 B
Rust
37 lines
945 B
Rust
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//! Binding relations: rows over named (variable) columns.
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//!
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//! Every operator in this crate (after the initial atom scan) consumes and
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//! produces [`Relation`]s. Column names are variable names; a value at column
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//! `i` of a row is the value bound to variable `columns[i]` in that solution.
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use crate::value::Value;
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#[derive(Debug, Clone)]
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pub struct Relation {
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pub columns: Vec<String>,
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pub rows: Vec<Vec<Value>>,
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}
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impl Relation {
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#[must_use]
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pub fn new(columns: Vec<String>) -> Self {
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Self {
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columns,
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rows: Vec::new(),
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}
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}
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/// # Panics
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/// Panics if `row.len() != self.columns.len()`.
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pub fn push(&mut self, row: Vec<Value>) {
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assert_eq!(
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row.len(),
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self.columns.len(),
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"row arity mismatch: expected {}, got {}",
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self.columns.len(),
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row.len(),
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);
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self.rows.push(row);
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}
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}
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