Bindgen our first struct

Cargo.lock

@@ -3439,6 +3439,7 @@ dependencies = [
  "bumpalo",
  "indoc",
  "pretty_assertions",
+ "regex",
  "roc_builtins",
  "roc_can",
  "roc_collections",
@@ -3446,9 +3447,11 @@ dependencies = [
  "roc_load",
  "roc_module",
  "roc_mono",
+ "roc_reporting",
  "roc_std",
  "roc_target",
  "roc_types",
+ "tempfile",
 ]
 
 [[package]]

bindgen/Cargo.toml

@@ -21,3 +21,8 @@ bumpalo = { version = "3.8.0", features = ["collections"] }
 [dev-dependencies]
 pretty_assertions = "1.0.0"
 indoc = "1.0.3"
+bumpalo = { version = "3.8.0", features = ["collections"] }
+regex = "1.5.5"
+roc_load = { path = "../compiler/load" }
+roc_reporting = { path = "../reporting" }
+tempfile = "3.2.0"

bindgen/src/bindgen_rs.rs

@@ -3,10 +3,16 @@ use crate::structs::Structs;
 use crate::types::RocType;
 use bumpalo::Bump;
 use roc_collections::MutMap;
-use roc_module::ident::Lowercase;
+use roc_module::{
+    ident::Lowercase,
+    symbol::{Interns, Symbol},
+};
 use roc_mono::layout::{Layout, LayoutCache};
 use roc_target::TargetInfo;
-use roc_types::subs::{Content, FlatType, RecordFields, Subs, Variable};
+use roc_types::{
+    subs::{Content, FlatType, RecordFields, Subs, Variable},
+    types::RecordField,
+};
 
 use std::{
     fmt::{self, Write},
@@ -81,9 +87,14 @@ pub fn write_roc_type(
     }
 }
 
+pub struct Env<'a> {
+    pub arena: &'a Bump,
+    pub layout_cache: &'a mut LayoutCache<'a>,
+    pub interns: &'a Interns,
+}
+
 pub fn write_layout_type<'a>(
-    arena: &'a Bump,
-    layout_cache: &mut LayoutCache<'a>,
+    env: &mut Env<'a>,
     layout: Layout<'a>,
     content: &Content,
     subs: &Subs,
@@ -93,6 +104,14 @@ pub fn write_layout_type<'a>(
     use roc_builtins::bitcode::IntWidth::*;
     use roc_mono::layout::Builtin;
 
+    let (opt_name, content) = match content {
+        Content::Alias(name, _variable, real_var, _kind) => {
+            // todo handle type variables
+            (Some(*name), subs.get_content_without_compacting(*real_var))
+        }
+        _ => (None, content),
+    };
+
     match layout {
         Layout::Builtin(builtin) => match builtin {
             Builtin::Int(width) => match width {
@@ -117,19 +136,19 @@ pub fn write_layout_type<'a>(
             Builtin::Str => buf.write_str("RocStr"),
             Builtin::Dict(key_layout, val_layout) => {
                 buf.write_str("RocDict<")?;
-                write_layout_type(arena, layout_cache, *key_layout, content, subs, buf)?;
+                write_layout_type(env, *key_layout, content, subs, buf)?;
                 buf.write_str(", ")?;
-                write_layout_type(arena, layout_cache, *val_layout, content, subs, buf)?;
+                write_layout_type(env, *val_layout, content, subs, buf)?;
                 buf.write_char('>')
             }
             Builtin::Set(elem_type) => {
                 buf.write_str("RocSet<")?;
-                write_layout_type(arena, layout_cache, *elem_type, content, subs, buf)?;
+                write_layout_type(env, *elem_type, content, subs, buf)?;
                 buf.write_char('>')
             }
             Builtin::List(elem_type) => {
                 buf.write_str("RocList<")?;
-                write_layout_type(arena, layout_cache, *elem_type, content, subs, buf)?;
+                write_layout_type(env, *elem_type, content, subs, buf)?;
                 buf.write_char('>')
             }
         },
@@ -141,7 +160,7 @@ pub fn write_layout_type<'a>(
                 Content::RigidAbleVar(_, _) => todo!(),
                 Content::RecursionVar { .. } => todo!(),
                 Content::Structure(FlatType::Record(fields, ext)) => {
-                    write_struct(arena, layout_cache, fields, *ext, subs, buf)
+                    write_struct(env, opt_name, fields, *ext, subs, buf)
                 }
                 Content::Structure(FlatType::TagUnion(tags, _)) => {
                     debug_assert_eq!(tags.len(), 1);
@@ -191,29 +210,55 @@ pub fn write_layout_type<'a>(
 }
 
 fn write_struct<'a>(
-    arena: &'a Bump,
-    layout_cache: &mut LayoutCache<'a>,
+    env: &mut Env<'a>,
+    opt_name: Option<Symbol>,
     record_fields: &RecordFields,
     ext: Variable,
     subs: &Subs,
     buf: &mut String,
 ) -> fmt::Result {
-    for (label, field) in record_fields.sorted_iterator(subs, ext) {
-        // We recalculate the layouts here because we will have compiled the record so that its fields
-        // are sorted by descending alignment, and then alphabetic, but the type of the record is
-        // always only sorted alphabetically. We want to arrange the rendered record in the order of
-        // the type.
-        let field_content = subs.get_content_without_compacting(field.into_inner());
-        let field_layout = layout_cache
-            .from_var(arena, field.into_inner(), subs)
-            .unwrap();
+    let mut pairs = bumpalo::collections::Vec::with_capacity_in(record_fields.len(), env.arena);
+    let it = record_fields
+        .unsorted_iterator(subs, ext)
+        .expect("something weird in content");
+    for (label, field) in it {
+        // drop optional fields
+        let var = match field {
+            RecordField::Optional(_) => continue,
+            RecordField::Required(var) => var,
+            RecordField::Demanded(var) => var,
+        };
+
+        pairs.push((
+            label,
+            var,
+            env.layout_cache.from_var(env.arena, var, subs).unwrap(),
+        ));
+    }
+
+    pairs.sort_by(|(label1, _, layout1), (label2, _, layout2)| {
+        let size1 = layout1.alignment_bytes(env.layout_cache.target_info);
+        let size2 = layout2.alignment_bytes(env.layout_cache.target_info);
+
+        size2.cmp(&size1).then(label1.cmp(label2))
+    });
+
+    let struct_name = opt_name
+        .map(|sym| sym.as_str(env.interns))
+        .unwrap_or("Unknown");
+    buf.write_str("struct ");
+    buf.write_str(struct_name);
+    buf.write_str(" {\n");
+
+    for (label, field_var, field_layout) in pairs.into_iter() {
+        let field_content = subs.get_content_without_compacting(field_var);
 
         buf.write_str(INDENT)?;
         buf.write_str(label.as_str())?;
         buf.write_str(": ")?;
-        write_layout_type(arena, layout_cache, field_layout, field_content, subs, buf)?;
+        write_layout_type(env, field_layout, field_content, subs, buf)?;
         buf.write_str(",\n")?;
     }
 
-    Ok(())
+    buf.write_str("}\n")
 }

bindgen/tests/gen_rs.rs

@@ -4,13 +4,142 @@ extern crate pretty_assertions;
 #[macro_use]
 extern crate indoc;
 
+use bumpalo::Bump;
 use core::mem;
 use roc_bindgen::{
-    bindgen_rs::write_roc_type,
+    bindgen_rs::{write_layout_type, write_roc_type, Env},
     enums::Enums,
     structs::Structs,
     types::{self, RocType},
 };
+use roc_can::{
+    def::{Declaration, Def},
+    pattern::Pattern,
+};
+use roc_load::LoadedModule;
+use roc_mono::layout::LayoutCache;
+use roc_reporting::report::RenderTarget;
+use roc_target::TargetInfo;
+use std::fs::File;
+use std::io::Write;
+use std::path::PathBuf;
+
+fn run_load_and_typecheck(
+    src: &str,
+    target_info: TargetInfo,
+) -> Result<(LoadedModule), std::io::Error> {
+    use bumpalo::Bump;
+    use tempfile::tempdir;
+
+    let arena = &Bump::new();
+
+    assert!(
+        src.starts_with("app"),
+        "I need a module source, not an expr"
+    );
+
+    let subs_by_module = Default::default();
+    let loaded = {
+        let dir = tempdir()?;
+        let filename = PathBuf::from("Test.roc");
+        let file_path = dir.path().join(filename);
+        let full_file_path = file_path.clone();
+        let mut file = File::create(file_path).unwrap();
+        writeln!(file, "{}", &src).unwrap();
+        let result = roc_load::load_and_typecheck(
+            arena,
+            full_file_path,
+            dir.path(),
+            subs_by_module,
+            roc_target::TargetInfo::default_x86_64(),
+            RenderTarget::Generic,
+        );
+
+        dir.close()?;
+
+        result
+    };
+
+    Ok(loaded.expect("had problems loading"))
+}
+
+pub fn generate_bindings(src: &str, target_info: TargetInfo) -> String {
+    let (LoadedModule {
+        module_id: home,
+        mut can_problems,
+        mut type_problems,
+        mut declarations_by_id,
+        mut solved,
+        interns,
+        ..
+    }) = run_load_and_typecheck(src, target_info).expect("Something went wrong with IO");
+
+    let decls = declarations_by_id.remove(&home).unwrap();
+    let subs = solved.inner_mut();
+
+    let can_problems = can_problems.remove(&home).unwrap_or_default();
+    let type_problems = type_problems.remove(&home).unwrap_or_default();
+
+    if !can_problems.is_empty() || !type_problems.is_empty() {
+        assert!(
+            false,
+            "There were problems: {:?}, {:?}",
+            can_problems, type_problems
+        );
+    }
+
+    let arena = Bump::new();
+    let mut layout_cache = LayoutCache::new(target_info);
+    let mut env = Env {
+        arena: &arena,
+        layout_cache: &mut layout_cache,
+        interns: &interns,
+    };
+
+    let mut bindgen_result = String::new();
+
+    for decl in decls.into_iter() {
+        let defs = match decl {
+            Declaration::Declare(def) => {
+                vec![def]
+            }
+            Declaration::DeclareRec(defs) => defs,
+            Declaration::Builtin(..) => {
+                unreachable!("Builtin decl in userspace module?")
+            }
+            Declaration::InvalidCycle(..) => {
+                vec![]
+            }
+        };
+        for Def {
+            loc_pattern,
+            pattern_vars,
+            ..
+        } in defs.into_iter()
+        {
+            match loc_pattern.value {
+                Pattern::Identifier(sym) => {
+                    let var = pattern_vars
+                        .get(&sym)
+                        .expect("Indetifier known but it has no var?");
+                    let layout = env
+                        .layout_cache
+                        .from_var(&arena, *var, &subs)
+                        .expect("Something weird ended up in the content");
+                    let content = subs.get_content_without_compacting(*var);
+
+                    write_layout_type(&mut env, layout, content, subs, &mut bindgen_result);
+                }
+                _ => {
+                    // figure out if we need to export non-identifier defs - when would that
+                    // happen?
+                }
+            }
+        }
+    }
+
+    bindgen_result
+}
 
 #[test]
 fn struct_without_different_pointer_alignment() {
@@ -40,3 +169,25 @@ fn struct_without_different_pointer_alignment() {
         out,
     );
 }
+
+#[test]
+fn my_struct_in_rust() {
+    let module = r#"app "main" provides [ main ] to "./platform"
+
+MyRcd : { a: U64, b: U128 }
+
+main : MyRcd
+main = { a: 1u64, b: 2u128 }
+"#;
+
+    let bindings_rust = generate_bindings(module, TargetInfo::default_x86_64());
+
+    assert_eq!(
+        bindings_rust,
+        "struct MyRcd {
+    b: u128,
+    a: u64,
+}
+"
+    );
+}

compiler/mono/src/layout.rs

@@ -1328,7 +1328,7 @@ impl<'a> Layout<'a> {
 /// But if we're careful when to invalidate certain keys, we still get some benefit
 #[derive(Debug)]
 pub struct LayoutCache<'a> {
-    target_info: TargetInfo,
+    pub target_info: TargetInfo,
     _marker: std::marker::PhantomData<&'a u8>,
 }