diff options
Diffstat (limited to 'dhall')
-rw-r--r-- | dhall/src/syntax/core/context.rs | 80 | ||||
-rw-r--r-- | dhall/src/syntax/core/mod.rs | 1 | ||||
-rw-r--r-- | dhall/src/syntax/mod.rs | 1 |
3 files changed, 0 insertions, 82 deletions
diff --git a/dhall/src/syntax/core/context.rs b/dhall/src/syntax/core/context.rs deleted file mode 100644 index 6844baa..0000000 --- a/dhall/src/syntax/core/context.rs +++ /dev/null @@ -1,80 +0,0 @@ -use std::cmp::Eq; -use std::collections::HashMap; -use std::hash::Hash; - -/// A `(Context a)` associates `Text` labels with values of type `a` -/// -/// The `Context` is used for type-checking when `(a = Expr)` -/// -/// * You create a `Context` using `empty` and `insert` -/// * You transform a `Context` using `fmap` -/// * You consume a `Context` using `lookup` and `toList` -/// -/// The difference between a `Context` and a `Map` is that a `Context` lets you -/// have multiple ordered occurrences of the same key and you can query for the -/// `n`th occurrence of a given key. -/// -#[derive(Debug, Clone)] -pub struct Context<K: Eq + Hash, T>(HashMap<K, Vec<T>>); - -impl<K: Hash + Eq + Clone, T> Context<K, T> { - /// An empty context with no key-value pairs - pub fn new() -> Self { - Context(HashMap::new()) - } - - /// Look up a key by name and index - /// - /// ```c - /// lookup _ _ empty = Nothing - /// lookup k 0 (insert k v c) = Just v - /// lookup k n (insert k v c) = lookup k (n - 1) c -- 1 <= n - /// lookup k n (insert j v c) = lookup k n c -- k /= j - /// ``` - pub fn lookup<'a>(&'a self, k: &K, n: usize) -> Option<&'a T> { - self.0.get(k).and_then(|v| { - if n < v.len() { - v.get(v.len() - 1 - n) - } else { - None - } - }) - } - - pub fn map<U, F: Fn(&K, &T) -> U>(&self, f: F) -> Context<K, U> { - Context( - self.0 - .iter() - .map(|(k, vs)| { - ((*k).clone(), vs.iter().map(|v| f(k, v)).collect()) - }) - .collect(), - ) - } - - pub fn lookup_all<'a>(&'a self, k: &K) -> impl Iterator<Item = &T> { - self.0.get(k).into_iter().flat_map(|v| v.iter()) - } - - pub fn iter(&self) -> impl Iterator<Item = (&K, &T)> { - self.0 - .iter() - .flat_map(|(k, vs)| vs.iter().map(move |v| (k, v))) - } - - pub fn iter_keys(&self) -> impl Iterator<Item = (&K, &Vec<T>)> { - self.0.iter() - } -} - -impl<K: Hash + Eq + Clone, T: Clone> Context<K, T> { - /// Add a key-value pair to the `Context` - pub fn insert(&self, k: K, v: T) -> Self { - let mut ctx = (*self).clone(); - { - let m = ctx.0.entry(k).or_insert_with(Vec::new); - m.push(v); - } - ctx - } -} diff --git a/dhall/src/syntax/core/mod.rs b/dhall/src/syntax/core/mod.rs index 66bf229..1950154 100644 --- a/dhall/src/syntax/core/mod.rs +++ b/dhall/src/syntax/core/mod.rs @@ -8,6 +8,5 @@ mod span; pub use span::*; mod text; pub use text::*; -pub mod context; pub mod map; pub mod visitor; diff --git a/dhall/src/syntax/mod.rs b/dhall/src/syntax/mod.rs index a82e827..6efa9cd 100644 --- a/dhall/src/syntax/mod.rs +++ b/dhall/src/syntax/mod.rs @@ -6,7 +6,6 @@ )] mod core; -pub use crate::syntax::core::context; pub use crate::syntax::core::visitor; pub use crate::syntax::core::*; pub use crate::syntax::text::parser::*; |