feat: Lower collections extension (#1720)

Closes #1701 and fixes #1645.

Note that destructors and ref-counting hooks are still missing. These
will follow in a future PR once they are available in hugr-llvm.

hugr-core/src/std_extensions/collections.rs

@@ -59,6 +59,16 @@ impl ListValue {
     pub fn custom_type(&self) -> CustomType {
         list_custom_type(self.1.clone())
     }
+
+    /// Returns the type of values inside the `[ListValue]`.
+    pub fn get_element_type(&self) -> &Type {
+        &self.1
+    }
+
+    /// Returns the values contained inside the `[ListValue]`.
+    pub fn get_contents(&self) -> &[Value] {
+        &self.0
+    }
 }
 
 impl TryHash for ListValue {

hugr-llvm/src/emit/func.rs

@@ -2,6 +2,7 @@ use std::{collections::HashMap, rc::Rc};
 
 use anyhow::{anyhow, Result};
 use hugr_core::{
+    extension::prelude::{either_type, option_type},
     ops::{constant::CustomConst, ExtensionOp, FuncDecl, FuncDefn},
     types::Type,
     HugrView, NodeIndex, PortIndex, Wire,
@@ -12,7 +13,7 @@ use inkwell::{
     context::Context,
     module::Module,
     types::{BasicType, BasicTypeEnum, FunctionType},
-    values::{BasicValueEnum, FunctionValue, GlobalValue},
+    values::{BasicValueEnum, FunctionValue, GlobalValue, IntValue},
 };
 use itertools::zip_eq;
 
@@ -314,3 +315,36 @@ impl<'c, 'a, H: HugrView> EmitFuncContext<'c, 'a, H> {
         Ok((self.emit_context, self.todo))
     }
 }
+
+/// Builds an optional value wrapping `some_value` conditioned on the provided `is_some` flag.
+pub fn build_option<'c, H: HugrView>(
+    ctx: &mut EmitFuncContext<'c, '_, H>,
+    is_some: IntValue<'c>,
+    some_value: BasicValueEnum<'c>,
+    hugr_ty: HugrType,
+) -> Result<BasicValueEnum<'c>> {
+    let option_ty = ctx.llvm_sum_type(option_type(hugr_ty))?;
+    let builder = ctx.builder();
+    let some = option_ty.build_tag(builder, 1, vec![some_value])?;
+    let none = option_ty.build_tag(builder, 0, vec![])?;
+    let option = builder.build_select(is_some, some, none, "")?;
+    Ok(option)
+}
+
+/// Builds a result value wrapping either `ok_value` or `else_value` depending on the provided
+/// `is_ok` flag.
+pub fn build_ok_or_else<'c, H: HugrView>(
+    ctx: &mut EmitFuncContext<'c, '_, H>,
+    is_ok: IntValue<'c>,
+    ok_value: BasicValueEnum<'c>,
+    ok_hugr_ty: HugrType,
+    else_value: BasicValueEnum<'c>,
+    else_hugr_ty: HugrType,
+) -> Result<BasicValueEnum<'c>> {
+    let either_ty = ctx.llvm_sum_type(either_type(else_hugr_ty, ok_hugr_ty))?;
+    let builder = ctx.builder();
+    let left = either_ty.build_tag(builder, 0, vec![else_value])?;
+    let right = either_ty.build_tag(builder, 1, vec![ok_value])?;
+    let either = builder.build_select(is_ok, right, left, "")?;
+    Ok(either)
+}

hugr-llvm/src/emit/test.rs

@@ -10,7 +10,7 @@ use hugr_core::ops::handle::FuncID;
 use hugr_core::std_extensions::arithmetic::{
     conversions, float_ops, float_types, int_ops, int_types,
 };
-use hugr_core::std_extensions::logic;
+use hugr_core::std_extensions::{collections, logic};
 use hugr_core::types::TypeRow;
 use hugr_core::{Hugr, HugrView};
 use inkwell::module::Module;
@@ -153,6 +153,7 @@ impl SimpleHugrConfig {
                         float_ops::EXTENSION_ID,
                         conversions::EXTENSION_ID,
                         logic::EXTENSION_ID,
+                        collections::EXTENSION_ID,
                     ]),
                 ),
             )

hugr-llvm/src/extension.rs

@@ -1,3 +1,4 @@
+pub mod collections;
 pub mod conversions;
 pub mod float;
 pub mod int;