add most of the RustGlue code (does not work yet)

crates/compiler/build/src/link.rs

@@ -1385,6 +1385,8 @@ fn run_build_command(mut command: Command, file_to_build: &str, flaky_fail_count
         command_string.push(arg);
     }
 
+    command.current_dir(std::env::current_dir().unwrap());
+
     let cmd_str = command_string.to_str().unwrap();
     let cmd_output = command.output().unwrap();
     let max_flaky_fail_count = 10;

crates/compiler/builtins/roc/List.roc

@@ -6,6 +6,9 @@ interface List
         replace,
         update,
         append,
+        appendIfOk,
+        prepend,
+        prependIfOk,
         map,
         len,
         withCapacity,
@@ -15,7 +18,6 @@ interface List
         single,
         repeat,
         reverse,
-        prepend,
         join,
         keepIf,
         contains,
@@ -321,6 +323,21 @@ append = \list, element ->
     |> List.reserve 1
     |> List.appendUnsafe element
 
+## If the given [Result] is `Ok`, add it to the end of a list.
+## Otherwise, return the list unmodified.
+##
+## ```
+## List.appendIfOk [1, 2, 3] (Ok 4)
+##
+## [0, 1, 2]
+##     |> List.appendIfOk (Err 3)
+## ```
+appendIfOk : List a, Result a * -> List a
+appendIfOk = \list, result ->
+    when result is
+        Ok elem -> append list elem
+        Err _ -> list
+
 ## Writes the element after the current last element unconditionally.
 ## In other words, it is assumed that
 ##
@@ -337,6 +354,21 @@ appendUnsafe : List a, a -> List a
 ## ```
 prepend : List a, a -> List a
 
+## If the given [Result] is `Ok`, add it to the beginning of a list.
+## Otherwise, return the list unmodified.
+##
+## ```
+## List.prepend [1, 2, 3] (Ok 0)
+##
+## [2, 3, 4]
+##     |> List.prepend (Err 1)
+## ```
+prependIfOk : List a, Result a * -> List a
+prependIfOk = \list, result ->
+    when result is
+        Ok elem -> prepend list elem
+        Err _ -> list
+
 ## Returns the length of the list - the number of elements it contains.
 ##
 ## One [List] can store up to 2,147,483,648 elements (just over 2 billion), which

crates/compiler/gen_dev/src/lib.rs

@@ -1941,7 +1941,12 @@ trait Backend<'a> {
                 self.build_eq(sym, &args[0], &Symbol::DEV_TMP, &arg_layouts[0]);
                 self.free_symbol(&Symbol::DEV_TMP)
             }
-            Symbol::LIST_GET | Symbol::LIST_SET | Symbol::LIST_REPLACE | Symbol::LIST_APPEND => {
+            Symbol::LIST_GET
+            | Symbol::LIST_SET
+            | Symbol::LIST_REPLACE
+            | Symbol::LIST_APPEND
+            | Symbol::LIST_APPEND_IF_OK
+            | Symbol::LIST_PREPEND_IF_OK => {
                 // TODO: This is probably simple enough to be worth inlining.
                 let fn_name = self.lambda_name_to_string(
                     func_name,

crates/compiler/module/src/symbol.rs

@@ -1434,6 +1434,8 @@ define_builtins! {
         82 LIST_UPDATE: "update"
         83 LIST_WALK_WITH_INDEX: "walkWithIndex"
         84 LIST_CHUNKS_OF: "chunksOf"
+        85 LIST_APPEND_IF_OK: "appendIfOk"
+        86 LIST_PREPEND_IF_OK: "prependIfOk"
     }
     7 RESULT: "Result" => {
         0 RESULT_RESULT: "Result" exposed_type=true // the Result.Result type alias

crates/glue/src/RustGlue.roc

@@ -5,6 +5,8 @@ app "rust-glue"
         pf.Shape.{ Shape, RocFn },
         pf.File.{ File },
         pf.TypeId.{ TypeId },
+        "../static/roc_fn/Cargo.toml" as rocFnCargoToml : Str,
+        "../static/roc_fn/src/lib.rs" as rocFnLibRs : Str,
         "../static/Cargo.toml" as rocAppCargoToml : Str,
         "../../roc_std/Cargo.toml" as rocStdCargoToml : Str,
         "../../roc_std/src/lib.rs" as rocStdLib : Str,
@@ -34,15 +36,24 @@ makeGlue = \typesByArch ->
 
                 """
 
-    typesByArch
-    |> List.map convertTypesToFile
-    |> List.append { name: "roc_app/src/lib.rs", content: modFileContent }
-    |> List.concat staticFiles
+    rocAppFiles =
+        typesByArch
+        |> List.map convertTypesToFile
+        |> List.append { name: "roc_app/src/lib.rs", content: modFileContent }
+
+    rocFnFile =
+        List.first typesByArch
+        |> Result.map convertEffectsToFile
+
+    staticFiles
+    |> List.concat rocAppFiles
+    |> List.appendIfOk rocFnFile
     |> Ok
 
 ## These are always included, and don't depend on the specifics of the app.
 staticFiles : List File
 staticFiles = [
+    { name: "roc_fn/Cargo.toml", content: rocFnCargoToml },
     { name: "roc_app/Cargo.toml", content: rocAppCargoToml },
     { name: "roc_std/Cargo.toml", content: rocStdCargoToml },
     { name: "roc_std/src/lib.rs", content: rocStdLib },
@@ -127,6 +138,44 @@ convertTypesToFile = \types ->
         content: content |> generateEntryPoints types,
     }
 
+convertEffectsToFile : Types -> File
+convertEffectsToFile = \_types ->
+    # TODO actually generate the effect types
+    # effectsStr = List.walk (Types.effects types) "" \accum, T name id -> generateEffect accum types name id
+    effectsStr = ""
+
+    {
+        name: "roc_fn/src/lib.rs",
+        content: Str.replaceFirst rocFnLibRs "// {{ROC_HOSTED_FNS}} //" effectsStr,
+    }
+
+# generateEffect : Str, Types, Str, TypeId -> Str
+# generateEffect = \buf, types, name, id ->
+#     { args, ret } =
+#         when Types.shape types id is
+#             Function rocFn ->
+#                 {
+#                     args:
+#                         rocFn.args
+#                         |> List.map \argId -> typeName types argId
+#                         |> Str.joinWith ", ",
+#
+#                     ret: typeName types rocFn.ret
+#                 }
+#
+#             _ ->
+#                 # This will compile to a thunk, e.g. `{} -> Ret`
+#                 { args: "", ret: typeName types id }
+#
+#     """
+#         \(buf)
+#         HostedFn {
+#             name: "\(name)",
+#             arg_types: &[\(args)],
+#             ret_type: \(ret),
+#         },
+#     """
+
 generateEntryPoints : Str, Types -> Str
 generateEntryPoints = \buf, types ->
     List.walk (Types.entryPoints types) buf \accum, T name id -> generateEntryPoint accum types name id
@@ -2016,6 +2065,7 @@ archName = \arch ->
         X86x64 ->
             "x86_64"
 
+fileHeader : Str
 fileHeader =
     """
     // ⚠️ GENERATED CODE ⚠️ - this entire file was generated by the `roc glue` CLI command
@@ -2037,7 +2087,6 @@ fileHeader =
     #![allow(clippy::clone_on_copy)]
 
 
-
     """
 
 indent = "    "